diff options
| author | nfenwick <nfenwick@pglaf.org> | 2025-01-23 07:20:33 -0800 |
|---|---|---|
| committer | nfenwick <nfenwick@pglaf.org> | 2025-01-23 07:20:33 -0800 |
| commit | d50a742fcfeef6b24f458afd4291427c74771c57 (patch) | |
| tree | c9112439fea4421e4d2a9936ea4c931497650918 /old/64754-0.txt | |
| parent | ec5fe6276fcd3842ac9b0ada3f89adb4de6365e8 (diff) | |
Diffstat (limited to 'old/64754-0.txt')
| -rw-r--r-- | old/64754-0.txt | 8037 |
1 files changed, 0 insertions, 8037 deletions
diff --git a/old/64754-0.txt b/old/64754-0.txt deleted file mode 100644 index 91909ad..0000000 --- a/old/64754-0.txt +++ /dev/null @@ -1,8037 +0,0 @@ -The Project Gutenberg eBook of Structure and Functions of The Body, by -Annette Fiske - -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you -will have to check the laws of the country where you are located before -using this eBook. - -Title: Structure and Functions of The Body - A Hand-Book of Anatomy and Physiology for Nurses and others - desiring a Practical knowledge of the Subject - -Author: Annette Fiske - -Release Date: March 08, 2021 [eBook #64754] - -Language: English - -Character set encoding: UTF-8 - -Produced by: MFR and the Online Distributed Proofreading Team at - https://www.pgdp.net (This file was produced from images - generously made available by The Internet Archive) - -*** START OF THE PROJECT GUTENBERG EBOOK STRUCTURE AND FUNCTIONS OF THE -BODY *** - - - - -Transcriber’s Notes: - - Underscores “_” before and after a word or phrase indicate _italics_ - in the original text. - Equal signs “=” before and after a word or phrase indicate =bold= - in the original text. - Small capitals have been converted to SOLID capitals. - Illustrations have been moved so they do not break up paragraphs. - Typographical and punctuation errors have been silently corrected. - - - - -[Illustration: The human skeleton (Lewis).] - - - - - STRUCTURE AND FUNCTIONS - _of_ - THE BODY - - A HAND-BOOK OF ANATOMY AND PHYSIOLOGY FOR - NURSES AND OTHERS DESIRING A PRACTICAL KNOWLEDGE - OF THE SUBJECT - - BY - ANNETTE FISKE, A. M. - - GRADUATE OF THE WALTHAM TRAINING SCHOOL FOR NURSES - - _ILLUSTRATED_ - - PHILADELPHIA AND LONDON - W. B. SAUNDERS COMPANY - 1911 - - Copyright, 1911, by W. B. Saunders Company - - PRINTED IN AMERICA - - PRESS OF - W. B. SAUNDERS COMPANY - PHILADELPHIA - - TO MY FATHER - and - TO DR. ALFRED WORCESTER - - as those who have perhaps most helped me in - the formation and realization of my ideals - this book is affectionately dedicated - - - - -PREFACE. - - -Although there are already in existence many books on anatomy and -physiology for nurses, none with which I am acquainted has seemed to me -to provide in concise form just the knowledge needed by the nurse in -her profession. Most of them, moreover, separate the anatomy from the -physiology and all treat the different systems of tissues separately, -first the bones, then the muscles, and so on. These defects, as they -seem to me, I have attempted to correct not only by weaving the -physiology in with the anatomy, but by treating first the general -structures found throughout the body and then describing the structure -and function of each part in detail. Thus, the first chapter is devoted -to a description of the general structure of all the tissues, a -separate chapter being devoted, however, to the skin, its appendages, -and function, including the sense of touch. Then the head with its -bones, muscles, and organs of special sense is described, while the -brain is treated with the rest of the nervous system, thus forming the -connecting link between the head and the body. In the same way the -back, chest, abdomen, pelvis, and extremities are taken up in turn and -the bones, muscles, blood-vessels, nerves, and special organs of each, -together with their functions, described. - -Although written more particularly for nurses I am in hopes that -this book may prove useful to any others who may desire to acquire a -practical knowledge of anatomy and physiology. - -Besides the usual text-books, I am much indebted for material to notes -taken in lecture courses given by Dr. Fred R. Jouett and Dr. F. J. -Goodridge of Cambridge, Mass., at the Cambridge School of Nursing, and -by Dr. Vivian Daniel of Watertown at the Waltham Training School for -Nurses. - -I wish particularly to express my gratitude and appreciation for the -kind and helpful criticism given me by Dr. Eugene A. Darling, Assistant -Professor of Physiology, Harvard College. - - ANNETTE FISKE. - _May, 1911._ - - - - -CONTENTS. - - - CHAPTER I. - PAGE - COMPOSITION AND GENERAL STRUCTURE OF THE BODY 11 - Chemical Constitution of the Body, 11--The Cell, 12--The - Fundamental Tissues of the Body, 13--Epithelial - Tissue, 14--Connective Tissue, 15--Structure of Bone, - 17--Bone Formation, 18--Chemical Composition of Bone, - 18--Classification and Function of Bones, 19--Joints, - 20--Muscle, 21--Action of the Muscles, 23--Physiology - of Muscle, 24--Cilia, 27--The Blood, 27--Arteries, - 27--Veins, 28--Capillaries, 28--Lymphatic System, - 29--Lymphatic Vessels, 31--Lymphatic Glands, - 32--Lymph, 32--Glands, 35--Ductless Glands, - 36--Nervous Tissue, 36. - - CHAPTER II. - THE SKIN, ITS APPENDAGES AND ITS FUNCTION 39 - The Skin, 39--Appendages of the Skin: Nails, 40--Hair, - 40--Sebaceous Glands, 41--Sweat Glands, 42--Sweat, - 42--Temperature Regulation, 43--Fever, 45--Sense of - Touch, 45--Touch Corpuscles, 46. - - CHAPTER III. - THE CRANIUM AND FACE 48 - The Cranial Bones, 48--Frontal Bone, 49--Parietal - Bones, 49--Occipital Bone, 50--Occipito-frontalis - Muscle, 51--Temporal Bones, 51--Sphenoid or Wedge - Bone, 52--Ethmoid Bone, 53--Turbinated Bones, - 53--Ossification of Sutures, 53--Bones of the - Face, 53--Superior Maxillary Bones, 54--Antrum of - Highmore, 54--Malar or Cheek Bones, 54--Lachrymal - Bones, 54--Palate Bones, 54--Nasal Bones, 55--Vomer, - 55--Inferior Turbinated Bones, 55--Inferior - Maxillary Bone or Lower Jaw, 55--Sublingual Gland, - 56--Submaxillary Gland, 56. - - CHAPTER IV. - THE ORGANS OF SPECIAL SENSE 57 - The Nose, 57--The Sense of Smell, 58--The Mouth, 59--The - Hyoid Bone, 60--The Teeth, 60--The Sense of Taste, - 61--Salivary Glands, 61--The Tonsils, 62--The Ear, - 63--Eustachian Tubes, 63--Sensation of Hearing, - 65--The Eye, 66--Lachrymal Gland, 68--Coats of the - Eye, 68--Light Rays and Sight, 70--Accommodation, - 72--Color Perception, 73. - - CHAPTER V. - THE NERVOUS SYSTEM 75 - The Cerebrum, 75--The Cerebellum, 78--Pons Variolii, - 78--Medulla Oblongata, 78--Spinal Cord, - 79--Brain-centers, 81--Motor Tract, 82--Sensory - Tract, 82--Reflex Action, 83--Cranial Nerves, - 83--Spinal Nerves, 84--Brachial Plexus, 85--Sacral - Plexus, 85--The Sympathetic System, 87--The - Sympathetic Nerves, 87. - - CHAPTER VI. - THE BACK 88 - The Spine, 88--The Vertebræ, 88--Muscles of the Neck, - 92--Muscles of the Back, 93. - - CHAPTER VII. - THE CHEST 96 - The Sternum, 97--The Ribs, 97--Costal Cartilages, - 98--Muscles of the Chest, 98--Diaphragm, 98--Mammary - Glands, 100. - - CHAPTER VIII. - THE HEART AND CIRCULATION 101 - The Heart, 101--The Pericardium, 101--Cavities of the - Heart, 103--The Endocardium, 103--The Valves of - the Heart, 103--Circulation, 105--Circulation in - the Fetus, 106--Arteries, 107--Veins, 109--Portal - Circulation, 109--Pulmonary Circulation, 110--Nerves - of the Heart, 110--Heart Sounds, 111--The Heart - Beat, 111--Factors Affecting Circulation, 112--The - Pulse, 113--Blood Pressure, 114--Nerve Supply of the - Blood-vessels, 115--The Blood, 116--Composition - of the Blood, 116--Coagulability of the Blood, - 117--Blood-corpuscles, 118. - - CHAPTER IX. - THE LUNGS AND RESPIRATION 121 - The Larynx, 121--The Trachea, 123--The Thyroid Gland, - 124--The Thymus Gland, 124--The Bronchi, 125--The - Lungs, 125--The Pleura, 125--The Mediastinum, - 126--Respiration, 127--Air, 129--Respiratory - Sounds, 129--Changes in Air in Lungs, 129--Effect - of Respiration on Blood, 130--Nervous Mechanism of - Respiration, 130--Variations in Respiration, 131. - - CHAPTER X. - THE ABDOMEN AND THE ORGANS OF DIGESTION AND EXCRETION 132 - The Abdominal Cavity, 132--Muscles of the Abdomen, - 132--The Peritoneum, 134--Abdominal Regions, - 134--Salivary Digestion, 136--The Pharynx, 139--The - Esophagus, 138--The Stomach, 138--Gastric Digestion, - 139--Vomiting, 140--Intestinal Canal, 141--The Small - Intestine, 142--Intestinal Digestion, 143--Absorption - in Intestine, 144--The Large Intestine, 145--Food and - Metabolism, 147--The Liver, 149--The Gall-bladder, - 152--The Pancreas, 153--The Spleen, 153--The - Suprarenal Capsules, 154--The Kidneys, 155--The - Urine, 156--The Ureters, 159--The Bladder and - Urethra, 159. - - CHAPTER XI. - THE PELVIS AND THE GENITAL ORGANS 161 - The Pelvis, 161--The Male Generative Organs, 164--The - Prostate Gland, 164--The Testes, 165--The Penis, - 165--The Female Generative Organs, 165--The Ovaries, - 165--The Fallopian Tubes, 166--The Uterus, 167--The - Vagina, 168--The External Genitalia in the Female, - 169--The Vulva, 169--The Mons Veneris, 169--The Labia - Majora, 169--The Labia Minora, 170--The Clitoris, - 170--The Meatus Urinarius, 170--The Hymen, 170--The - Fourchette, 170--The Perineal Body, 170--The - Perineum, 170. - - CHAPTER XII. - THE UPPER EXTREMITIES 171 - The Shoulder Girdle, 171--The Clavicle, 171--The Scapula, - 173--Shoulder Muscles, 174--The Humerus, 175--Upper - Arm Muscles, 176--The Ulna, 177--The Radius, - 178--The Wrist, 180--The Hand, 181--Meta-carpals, - 181--Phalanges, 181--Muscles of the Forearm, - 182--Muscles of the Hand, 184--Joints of the Upper - Extremity, 185--Blood Supply of the Upper Extremity, - 185--Nerves of the Upper Extremity, 186. - - CHAPTER XIII. - THE LOWER EXTREMITIES 187 - The Femur, 187--Thigh Muscles, 189--The Patella, - 192--Joints of the Lower Extremity, 192--The Tibia, - 194--The Fibula, 194--The Ankle, 195--The Foot, - 195--Metatarsals, 195--Phalanges, 195--Muscles of the - Leg, 196--The Blood Supply of the Lower Extremity, - 198--Nerves of the Lower Extremity, 199. - - INDEX 201 - - - - -STRUCTURE AND FUNCTIONS OF THE BODY. - - - - -CHAPTER I. - -COMPOSITION AND GENERAL STRUCTURE OF THE BODY. - - -Anatomy is the study of the physical structure and physiology the study -of the normal functions of the human body. - -=Chemical Constitution of the Body.=--In the body only twenty elements -have been found. These include carbon, oxygen, hydrogen, nitrogen, -sulphur, phosphorus, calcium, magnesium, manganese, chlorin, potassium, -and fluorin. For the most part they appear in very complex and highly -unstable combinations, though oxygen and nitrogen may be said to exist -uncombined in the blood, alimentary canal, and lungs. Hydrogen also -occurs in simple form in the alimentary canal, but as the result of -fermentation, not as an element of the body. - -Of the organic compounds some contain nitrogen and some do not. The -most important of the former are the proteins, which are found only in -living bodies and consist of carbon, hydrogen, oxygen, nitrogen, and -sulphur combined in very similar proportions. The important proteins in -the body are the serum albumen and fibrin found in the blood, myosin in -muscle, globulin in the red blood-corpuscles, and casein in the milk. -Similar to the proteins but capable of passing through membranes are -the peptones, the final result of protein digestion, from which the -albuminoids differ in that they contain no sulphur. Ferments containing -nitrogen exist in all the cells of the body, though more particularly -in those of the digestive organs, and the coloring matters, as the -bilirubin of the bile, are nitrogenous. - -The organic substances that do not contain nitrogen are the -carbohydrates or starches, the hydrocarbons or fats, and the acids, of -which the most important is carbon dioxide, given off by the lungs. - -The inorganic substances are water, which forms a large percentage of -all the tissues and from one-fourth to one-third of the whole body -weight, sodium chloride or common salt, which plays an important part -in keeping substances in solution, potassium and magnesium chloride, -and hydrochloric acid, found in the stomach. - -=The Cell.=--Although the body is a very complex organism, the cell -is its unit or foundation. In fact, the body begins life as a single -protoplasmic cell, the ovum, which is frequently compared to the -amœba, a microscopic animal consisting of a single cell of protoplasm -or living substance--a substance not well understood as yet--but -possessing practically all the functions of the human body. For, -although it has no organs and is homogeneous in structure, the amœba -can move by throwing out a process, and can surround and absorb food, -which it builds up into new tissue, discarding the waste. The ovum, -however, differs from the amœba in that it has a transparent limiting -membrane and contains a darker spot, the nucleus. This in turn contains -another smaller spot, the nucleolus, while through the protoplasm, -which is semi-fluid, extends a fine network that seems to hold it in -place. - -The _ovum_ is very small, about ¹/₁₂₅ inch in diameter, and after -fertilization grows by segmentation, the nucleus dividing in two and -the protoplasm grouping itself anew about the two nuclei. This division -continues, each cell dividing and forming two, or sometimes four, -new cells, all of which at first appear alike. By degrees, however, -differentiation takes place and different groups of cells assume -different characteristics. Thus the various tissues are gradually -developed, each with a structure and a function of its own, and are -distributed among the various organs, each organ consisting of several -tissues. During the process of growth and even after full growth of the -body is attained old cells are continually dying and being replaced by -new ones. - -The typical cell is circular, but through being squeezed together -in the tissues or for some other reason the cells vary in shape in -different parts, being at times hexagonal, spindle-shaped, or columnar. -Yet, whatever their differences in shape or other characteristics, they -all live the same sort of life. All protoplasm absorbs oxygen when it -comes in contact with it and in the process of combining with it is in -part burned or oxidized, with the consequent setting free of heat and -other forms of energy and the formation of carbon dioxide. So long as -the body is alive, therefore, whether it is in a state of activity or -of rest, it is the seat of constant chemical change throughout all its -cells, and to these chemical changes are due all the forms of energy -manifested by the body. For energy is never destroyed, though it may -appear in a different form, and the elements of the human body are -so combined that their energy may be liberated and manifested in the -different functions the body exhibits. - -=The fundamental tissues of the body= are the epithelial tissues, the -connective tissues, including the cartilaginous and bony tissues, and -the muscular and nervous tissues. Of these the epithelial tissues serve -as a protection to the surface of other tissues; the connective tissues -together form a framework for the support and general protection of the -other tissues; while energy is expended by muscular and nervous tissue, -the latter directing the former in its movements. All the tissues are -inter-dependent and the organs work together. Besides cells every -tissue contains a certain amount of lifeless matter, the intercellular -substance, which was at some time produced by the cells. - -[Illustration: FIG. 1.--Epithelium: 1, pavement epithelium; 2, columnar -epithelium; 3, ciliated epithelium; 4, stratified epithelium.] - -In =epithelial tissue= there is little intercellular substance, the -cells being close together and arranged generally as a skin or membrane -covering external or internal surfaces. When there are several layers -of cells, the deepest are columnar in shape and the others become -more and more flattened and scale-like as they approach the surface, -where they are gradually rubbed off and replaced by the growth of new -cells from below. This stratified epithelium, as it is called, is -found wherever a surface is exposed to friction, as in the skin and -in the mucous membrane of the mouth, pharynx, and esophagus, and in -that of the vagina and the neck of the uterus. In simple epithelium, -where there is only a single layer of cells, the cells may be pavement -or hexagonal, columnar, glandular, or ciliated, according to their -different functions. The flat pavement cells occur where a very smooth -surface is required, as in the heart, lungs, blood-vessels, serous -cavities, etc. None of these surfaces communicate directly with the -external surface of the body and the name endothelium is substituted -for epithelium. The columnar form of cell in the intestine facilitates -the passage of leucocytes between the cells. In glandular epithelium -the cells vary according to the gland in which they occur, their -protoplasm being filled with the material the gland secretes. Finally, -ciliated epithelium is composed of columnar cells with cilia or little -hair-like processes upon their free surface which serve to send -secreted fluids and other matters along the surfaces where they occur, -as in the air passages, parts of the generative organs, the ventricles -of the brain, and the central canal of the spinal cord. - -=Connective tissue= has a great deal of intercellular substance. One -form, _areolar tissue_, is composed of a loose network of fine white -fibers with a few yellow elastic fibers interspersed and with cells -lying in the spaces between the fibers. It connects and surrounds the -different organs and parts, holding them together, yet allowing free -motion, and is one of the most extensively distributed of the tissues. -It is continuous throughout. - -[Illustration: FIG. 2.--Section of bladder epithelium. (Hill.)] - -Closely allied to the areolar is the _fibrous tissue_, in which the -white fibers lie close together and run for the most part in one -direction only. This is found in ligaments, joints and tendons, as also -in such fibrous protective membranes as the periosteum, dura mater, the -fasciæ of muscles, etc. Fibrous tissue is silvery white in appearance -and is very strong and tough, yet pliant. It is not extensile. - -_Elastic tissue_, on the other hand, has a large predominance of -yellow elastic fibers and is very extensile and elastic, though not so -strong as the fibrous. It is found in the walls of the blood-vessels, -especially the arteries, in the walls of the air tubes, in the -ligaments of the spine, etc. - -_Fatty or adipose tissue_ is formed by the deposit of fat in the cells -of the areolar tissue and is found in most parts where the areolar -tissue occurs, though it varies largely in amount in different parts. -It is found pretty generally under the skin, fills in inequalities -about various organs and about the joints, and exists in large -quantities in the marrow of the long bones. In moderate amounts it -gives grace to the form and constitutes an important reserve fund. - -[Illustration: FIG. 3.--Adipose tissue (Leroy): _a_, Fibrous tissue; -_b_, fat cells; _c_, nucleus of fat cells; _d_, fatty acid crystals in -fat cells.] - -_Cartilage_ consists of groups of nucleated cells in intercellular -substance. It is very firm, yet highly elastic, and serves in the -joints to break the force of concussion of the harder and less elastic -bones. Except when it occurs at the end of a bone, it is covered with -a membrane called the perichondrium, which carries its blood supply. -In the nose, ear, larynx and trachea it serves to give shape, to keep -the passages open, and to afford attachment for muscles. Most of the -skeleton of the fetus consists of cartilage, which later develops into -bone. - -_Bone._--In bone the intercellular tissue is rendered hard by the -deposit of mineral salts, the resulting material being of great -strength and rigidity. The texture may be close and dense like ivory or -open and spongy, the difference lying merely in the fact that the one -has fewer spaces between the solid particles than the other. There is -usually a hard, compact layer on the exterior of the bone, as that is -where the greatest cross-strain comes, especially in the long bones, -while within is the cancellous or spongy tissue, which gives lightness -to the bone and is capable of withstanding enormous pressure, though it -can bear little cross-strain. - -[Illustration: FIG. 4.--Cross-section of compact bone tissue. (After -Sharpey.)] - -=Structure of Bone.=--The hard substance in bone is always arranged -in lamellæ or bundles of bony fibers, which in cancellous tissue -meet to form a kind of lattice-work, while in the dense tissue they -are generally arranged in rings about the Haversian canals, channels -through which the blood-vessels pass through the bone longitudinally. -Between the lamellæ are spaces called _lacunæ_, in which lie branched -cells, the spaces being connected with each other and with the -Haversian canals by numerous tiny canals or canaliculi, by which -nutrient material finds its way from the Haversian canals to all parts -of the bone. - -Within the bone is the medulla or _marrow_, which is of two varieties: -the yellow, which is largely fat and is found in the long bones of -adults, and the red, which is nearly three-fourths water and is found -in most of the other adult bones and in the bones of the fetus and of -the infant. - -Lining the medullary and cancellous cavities is a delicate connective -tissue lining, the _endosteum_, which contains many bone-forming cells, -while on the outside of the bone, except at the articular ends, is the -_periosteum_ with its outer protective layer and its inner vascular -layer containing osteoblasts or bone-forming cells. The periosteum is -essential for the growth of new bone where the old bone has died, and -if the periosteum is removed from healthy bone the part beneath is -liable to die, as it is by the constant growth of the osteoblasts that -the bone grows and is renewed. In the repair of broken bones tissue is -formed between and around the broken ends. - -=Bone Formation.=--Most of the skull and face bones begin as -membranes of connective tissue, that is, are formed in membrane. -Bones are also formed in cartilage, the bone formation in this case -beginning from centers of ossification, where the deposit of lime -salts in the intercellular substance begins, the salts coming to the -centers dissolved in the plasma. Such a center of growth in a bone -is called the epiphysis and is separated from the main part of the -bone or diaphysis by cartilage until full growth is attained, when -ossification becomes complete. So in surgery, in working on the bones -of children, part of the epiphysis should always be left for the sake -of future growth. The outer shell of compact tissue is deposited by the -periosteum. - -=Chemical Composition of Bone.=--Chemically bone is composed of about -one-third organic or animal matter, largely gelatine, and two-thirds -inorganic matter, including various salts of calcium, magnesium, and -sodium. In young children the animal matter predominates and the bones -are soft and often bend instead of breaking, only the outside shell on -one side giving way, as in “green-stick” fracture. In rickets there is -a deficiency of lime salts, but the increased brittleness of the bones -in old age is due, not to increase of mineral matter, but to the less -spongy texture of old bones. - -=Classification and Function of Bones.=--There are in the body some -two hundred bones, which may be classified as long, short, flat, and -irregular. Occasionally an irregular bone develops in a fontanelle, the -membranous opening at the juncture of the sutures of the skull. This -is known as a Wormian bone. It is not, however, included in the two -hundred, as are not the sesamoid bones or bones developed in tendons, -with the exception of the patella or knee-cap. - -Long bones are developed in cartilage and consist of a shaft, two -extremities, and various processes. They are more or less curved to -give them strength and grace. They serve as supports and act as levers -for purposes of motion and the exercise of power. Since a hollow -cylinder is just as strong as a solid one of the same size, the weight -coming only on the outer shell, the great bones which are accountable -for weight and which need to be light themselves have hollow shafts, -composed chiefly of compact tissue with a central medullary canal. The -ends, however, are expanded in order to make better connection at the -joints and to afford broad surfaces for muscular attachment, cancellous -tissue being used in them for lightness and strength. The large spongy -ends also give elasticity and lessen jar, and by bringing the tendons -to the bone at a greater angle increase their effectiveness. Blood is -brought to the long bones not only by the vessels of the periosteum but -by the medullary artery, which penetrates the compact tissue by the -nutrient foramen and divides into an ascending and a descending branch. - -Short bones are spongy throughout. They are used for strength and where -little motion is required. - -Flat bones are composed of two thin layers of compact tissue with a -varying amount of cancellous tissue between, and are for protection and -muscular attachment. The cancellous material between the two layers or -tablets of the skull is called the diploë. - -Eminences and depressions occur on bones and when they are not -articular are for the attachment of ligaments and muscles. If they are -articular, they help to form joints. - -As a whole the bony framework serves to keep the soft parts in place, -to support and protect them, and to aid in locomotion. The bones of the -head and trunk support and protect organs; those of the arms are for -tact and prehension; those of the lower extremities are for support and -locomotion. - -Normally bones have little sensibility, but when inflamed they are -extremely sensitive and painful. - -=Joints.=--The bones are connected with and move upon one another by -means of joints. These joints are of three kinds: 1. Immovable, where -the adjacent margins of the bones are closely applied, with little -fibrous tissue between, as in the sutures of the head; 2. those with -limited motion, which are very strong, the parts being connected with -tough fibro-cartilage; and 3. freely movable. In this last group the -articulating surfaces are covered with cartilage, which again is -lined with a delicate synovial membrane which secretes a small amount -of lubricating fluid, the synovial fluid, to reduce friction. Their -surfaces are also sometimes deepened by the presence of inter-articular -fibro-cartilages. Bursæ or sacs of synovial membrane occur outside the -joints under tendons and ligaments to reduce friction. - -The nature and extent of the motion of a joint is defined and the bones -are held together by strong bands of fibrous tissue or ligaments, these -ligaments being more fully developed in joints where there is great -freedom of motion or where there is great weight to be supported. In a -ball-and-socket joint, such as the hip, there is a ligament in the form -of a strong capsule which surrounds the joint on all sides and limits -its motion, while hinge joints, like the elbow, and pivot joints, such -as that formed by the atlas on the axis, have lateral ligaments that -allow of freer motion. In the shoulder-joint, which is the most freely -movable joint in the body, the capsular ligament is very lax. - -In general the kinds of motion possible in joints may be said to be -flexion, extension, abduction, adduction, circumduction, and rotation. - -When much violence is applied to a joint and no dislocation results, as -in a sprain, there is often much stretching and even laceration of the -ligaments. - -=Muscle.=--The flesh, which forms a large proportion of the weight of -the body, consists of muscular tissue. Of this two kinds are found: -1. The striated or striped muscle of animal life, which is under the -control of the will and so is known as voluntary muscle, and 2. the -unstriped or smooth muscle of organic life over which we have no -control, that is, the involuntary muscle. Each fiber of striped muscle -has an elastic, membranous sheath, the sarcolemma, and consists of -rod-shaped cells with a nucleus along the edge, set end to end and -having crosswise striations. In unstriated muscle the fibers, which -have no sarcolemma, consist of oval or spindle-shaped cells, with -a nucleus much smaller than that of striped muscle and situated in -the middle. In both kinds of muscle the fibers are bound together -with connective tissue and blood-vessels into fasciculi or bundles, -and many bundles go to make up a muscle. The muscle in turn has a -connective tissue envelope or sheath, the fascia. These fasciæ are -found throughout the body, the superficial ones being just beneath -the skin, while the deep ones not only form sheaths for the various -muscles but form partitions between them and serve to strengthen their -attachments. The striped muscles are those of motion, while the -unstriped occur in the hollow organs, surrounding the cavity and in -some cases lessening its capacity by their contraction. - -An intermediate form of muscle known as cardiac muscle occurs in the -heart. Here the fibers have striations but the nucleus is generally in -the middle of the cell and the fibers branch and run together. - -[Illustration] - -[Illustration: FIG. 5.--Voluntary muscle (Leroy). _A_, Three voluntary -fibers in long sections: _a_, three voluntary muscle fibers; _b_, -nuclei of same; _c_, fibrous tissue between the fibers (endomysium); -_d_, fibers separated into sarcostyles. _B_, Fiber (diagrammatic): _a_, -dark band; _b_, light band; _c_, median line of Hensen; _d_, membrane -of Krause; _e_, sarcolemma; _f_, nucleus. _C_: _a_, Light band; _b_, -dark band; _c_, contracting elements; _d_, row of dots composing the -membrane of Krause; _e_, slight narrowing of contracting element aiding -in production of median line of Hensen.] - -In life muscle appears more or less translucent and is contractile and -alkaline, but in death it loses its translucency and becomes rigid, -at the same time giving off in decomposition much carbon dioxide, so -that its reaction is acid. This phenomenon of the muscles becoming -rigid in death is called rigor mortis and occurs generally a few hours -after death, though it may come at once or be considerably delayed. -It may last anywhere from a few moments to several days but generally -lasts from twenty-four to thirty-six hours. It is probably due to the -formation in the muscle of myosin, a substance which probably comes -from myosinogen in the living muscle and which is closely akin to -the fibrin of blood. Probably the myosin or what precedes it causes -clotting of the muscle just as fibrin or what precedes it causes -clotting of the blood. - -[Illustration: FIG. 6.--Three voluntary muscle fibers from an injected -muscle, showing network of blood capillaries. (Hill.)] - -The muscles vary in shape in different parts of the body, being long -and slender in the limbs and broad and flat in the trunk. They are -attached chiefly to bones but also to cartilages, ligaments, and skin, -either by means of tendons, which are cords or bands of white inelastic -fibrous tissue, or by means of aponeuroses, membranous expansions of -the same nature. Most voluntary muscles consist of a belly and two ends -or tendons. The origin is the fixed point from which it acts while the -movable point upon which it acts is known as its insertion. - -=Action of the Muscles.=--When attached to bones, muscles are -distributed in three ways: 1. When it is necessary to produce much -motion rapidly, a short muscle is used. 2. When a part needs to be -moved far and much contraction on the part of the muscle is, therefore, -needed, the muscle is very long, as in the case of the sartorius -muscle, which shortens half its length. 3. Finally, where less distance -has to be covered but greater power is required, tendons are used, as -in this case the contraction is powerful but does not carry the part -far. - -In performing the mechanical work of the body the muscles are aided by -the fact that the bones, to which they are largely attached, are set -together loosely and form a set of levers, on which the muscles act -to perform certain definite acts. All three classes of levers occur: -1. where the fulcrum is between the weight and the power, as in the -case of the head, which is balanced by the muscles of the neck on the -vertebræ; 2. where the weight is between the fulcrum and the power, as -when a person raises himself upon his toes; and 3. where the power is -between the fulcrum and the weight, as when the biceps is used to raise -a weight held in the hand. The erect position of the body is difficult -to maintain because the center of gravity is high up, and it is by the -contraction of many muscles in the legs, thighs, back, abdomen, and -neck that the body is balanced upright upon the feet. - -=Physiology of Muscle.=--_Irritability_ or sensitiveness to stimulation -and _contractility_ or the power to contract are the two most important -functions of muscle. Contraction occurs in response to nervous energy -brought by the nerves, a nerve filament going to each muscle fiber, -into which it plunges, its substance being lost and its sheath -becoming continuous with that of the muscle fiber. Any irritant, -as heat, electricity, etc., when applied to the nerve, causes the -muscle to contract. Moreover, muscle has an irritability of its own -and can contract independently of the nervous system. In contracting -it shortens and thickens, bringing the two ends closer together, and -becomes firm and rigid. The amount of contraction depends upon the -strength of the stimulus and the irritability of the muscle. The -minimal stimulus is the least stimulus that will cause a contraction -and the maximal is one that will cause the greatest contraction. The -work done depends in like manner upon the strength of the stimulus. -During contraction certain sounds are given off called muscle sounds, -which can be heard with the stethoscope but have no special -significance. - -The muscles which have the greatest power of rapid contraction are -generally attached to levers. Indeed, striated muscle is characterized -by the rapidity and strength with which it works, though its rhythmic -motion is slight. Smooth muscle, on the other hand, is characterized -by its great force, considerable rhythm, considerable tone, and slight -rapidity, that is, its contraction is slower and lasts longer than that -of striated muscle. Cardiac muscle is characterized by great rhythm and -force, fair rapidity, and slight tonicity, tonicity being the amount of -tone or readiness to work. For even in sleep muscle is always in tone, -that is, ready to do its work. It is this that makes the difference in -appearance between a living and a dead person and enables one to spring -to his feet at night if he hears a noise, a thing he could not do if -his muscles were wholly relaxed. Thus, rapidity is the great function -of striated, tonicity of smooth, and rhythm of cardiac muscle. In -paralysis the muscles droop and lose their tone. Muscles are frequently -the seat of rheumatic disorders. - -When set free, potential energy accomplishes work. In muscle there is -a good deal of potential energy, which is set free as heat and as work -accomplished. Even when the muscles are at rest, chemical changes are -going on and heat is being produced, though more heat is produced when -they are functioning. If the body depended upon its gross motions for -all its heat it would grow cold while a person rested. The respiratory -organs, however, and the heart are always working and chemical changes -are constantly taking place. - -Ordinarily a muscle has some object in contracting, such as the raising -of a load, and it contracts voluntarily more or less according to -the weight of the load. The amount of work done is calculated in -foot-pounds or gram-meters, that is, the energy required to raise one -pound one foot or one gram one meter. As a rule the muscles with the -longest fibers, as the biceps, do the most work and those with a large -number of fibers do more than those with less. It has been calculated -that whereas an engine gives back one-twelfth of the energy of the coal -consumed, muscle liberates one-fourth of the energy brought to it in -the form of food. During activity the glycogen or sugar in the muscle -is used up and the muscle becomes more acid, owing to the lactic acid -that is formed. The carbon is taken in and carbon dioxide given off. -Nitrogen puts the muscle in condition to do its work but is not so -much used up in the work as is the carbohydrate material. So it is the -non-nitrogenous matter that does the work and any increase in urea, the -end-product of protein metabolism, is mere wear and tear. - -Sudden heat or cold causes muscular contraction and moderate heat -favors both muscular and nervous irritability. Moderate cold, however, -lessens the force of contraction and below zero muscle very largely -loses its irritability without necessarily becoming rigid. - -While well supplied with blood, muscle will contract without fatigue, -but if the blood supply is shut off, it soon loses its irritability -and becomes rigid. The more a muscle is used in moderation the more it -develops, but after it has done a certain amount of work it becomes -exhausted, losing its irritability or power to respond to stimuli -and later becoming rigid. Such fatigue is due to the production of -certain poisonous waste products which have a paralyzing effect on the -nerves and which are ordinarily gradually carried away in the blood, -but which sometimes, if produced to excess, accumulate too fast for -the blood wholly to remove them. Usually the nerve becomes exhausted -first and the muscle substance later. So long as it is connected with -the nervous system a muscle will respond to stimuli, but when the -nerve becomes tired, degeneration is more rapid. In fact, the degree -of exhaustion is determined by several factors, as by relation to the -central nervous system, variations in temperature, blood supply, and -functional activity, the process being more rapid in warm than in cold -blooded animals. - -=Cilia.=--A few motions are accomplished by tissue that is not -muscular, as in the case of the cilia attached to the cells of the -respiratory tract, which lie flat on the free surface and then lash -forward, serving in the air cells to keep the air in motion and in the -tubes to send secretions from below upward and outward and to keep out -foreign bodies. Cilia are also found in the female genital tract, where -they aid the passage of the ovum from the ovary to the womb. They act -together, though apparently not governed by the nervous system. As in -the white corpuscles of the blood, whose motion also is not muscular, -the changes that take place in ciliated epithelium are probably about -the same as those in muscular tissue, that is, contractile. - -=The Blood.=--To most of the tissues just described nourishment is -brought in the blood, which circulates through the body in a system -of hollow tubes, the arteries and veins, whence it is distributed -through the agency of the lymphatic system. There are no blood-vessels, -however, in the epidermis, epithelium, nails, hair, teeth, nor in the -cornea of the eye. The vessels that carry the blood from the heart -are called arteries, those that return it veins. The former begin as -large vessels and gradually decrease in size; the latter begin as small -vessels and form larger and larger trunks as they approach the heart. - -The _arteries_ have three coats: 1. a thin, serous coat, the internal -or intima; 2. a middle or muscular coat, and 3. an external coat of -connective tissue. The middle coat is the thickest and is the one that -prevents the walls from collapsing when cut across. Except in the -cranium, each artery is enclosed in a sheath with its vein or veins, -the venæ comites. Usually the arteries occupy protected situations and -are straight in their course. Where a vessel has to accommodate itself -to the movements of a part, however, it may be curved, as in the case -of the facial artery which is curled on itself to allow for movements -of the jaw. They anastomose or communicate freely with one another, -thus promoting equality of distribution and pressure and making good -circulation possible even after the obliteration of a large vessel. - -The _veins_ have three coats like the arteries, but they are not so -thick and the muscular coat is not so highly developed, so that the -walls collapse when cut and have no elasticity. There are constrictions -on the surface of many of the veins due to the presence of valves. -These valves are formed of semilunar folds of the lining membrane -and are arranged in pairs. They serve to prevent the blood, whose -circulation in the veins is sluggish, from flowing back. - -There are two sets of veins, the superficial and the deep, which -communicate with each other. In fact, all the veins, large and small, -anastomose very freely, especially in the skull and neck, where -obstruction would result in serious trouble, throughout the spinal -cord, and in the abdomen and pelvis. The deep veins accompany the -arteries in their sheath, while the superficial ones have thicker walls -and run between the layers of the superficial fascia under the skin, -terminating in the deep veins. In the skull the venous channels take -the form of sinuses, formed by a separating of the layers of the dura -mater, with an endothelial lining that is continuous with that of the -veins. - -The _capillaries_ are intermediate between the arteries and the veins, -the final division of the arteries and the first source of the veins. -They are tiny vessels with but a single coat, continuous with the -innermost coat of both arteries and veins and consisting practically of -one layer of cells with a small amount of connective tissue between. -They spread in a great network throughout the tissues, forming plexuses -and being especially abundant where the blood is needed for other -purposes than local nutrition, as in the secreting glands. Their -diameter is so small that the red corpuscles have to pass in single -file and may even then be squeezed out of shape. As they have no -muscular tissue in their walls, they have no power of contracting. -Their walls, however, like those of the smaller arteries and veins, are -porous and by virtue of this quality they play an important part in the -economy, since in them the exchange takes place between the tissues and -the blood. - -The arteries in general carry freshly oxidized blood and the veins -blood from which the oxygen has been largely used up and which contains -waste material. In the pulmonary system, however, the case is reversed, -the pulmonary arteries conveying venous blood, as it is called, from -the heart to the lungs to be oxidized and the veins returning the blood -after it has received its new supply of oxygen. - -The pumping of the blood through the arteries is assisted by the -contractions of the muscular coat, while the elastic tissue, of which -it contains a certain amount, gives elasticity to the walls and enables -them to stretch and so to accommodate the larger blood supply forced -into them at each beat by the heart. The walls of the veins have not -the power of contracting and the blood is pushed through more by -gravity and the action of the arteries than by any action of their own. - -The walls of all the vessels are nourished by tiny blood-vessels in -the outer coat, known as _vasa vasorum_, and the nerves that regulate -the action of the arteries are the vasomotor nerves from the vasomotor -center in the medulla. Sufficient impulse goes from this center to the -blood-vessels all the time to keep them somewhat contracted, in a state -of tone, that is, which is increased or diminished as the blood supply -is to be diminished or increased. - -=Lymphatic System.=--The lymphatic system also extends throughout -the body and consists of a system of channels, spaces, and glands -very closely related to the circulatory system and containing a fluid -called lymph. There are three principal parts to the system: 1. the -lymph spaces, which are open spaces, with no definite walls, in the -connective tissue framework of the body, more frequent near arteries -and veins and especially so among the capillaries; 2. the lymph -capillaries or small vessels which connect the lymph spaces; and 3. the -lymphatic vessels, of which there is a deep and a superficial set, the -latter accompanying the superficial veins on the surface of the body, -the former accompanying the deep blood-vessels. - -[Illustration: FIG. 7.--Diagram showing the course of the main trunks -of the absorbent system: the lymphatics of lower extremities (D) meet -the lacteals of the intestines (LAC) at the receptaculum chyli (R.C.), -where the thoracic duct begins. The superficial vessels are shown in -the diagram on the right arm and leg (S), and the deeper ones on the -left arm (D). The glands are here and there shown in groups. The small -right duct opens into the veins on the right side. The thoracic duct -opens into the union of the great veins of the left side of the neck -(T). (Yeo.)] - -The _lymph spaces_ are generally small, though there are some large -serous cavities, such as the abdomen, that may be considered as -extended lymph spaces. - -[Illustration: FIG. 8.--Diagram of a lymphatic gland, showing afferent -(_a. l._) and efferent (_e. l._) lymphatic vessels; cortical substance -(_C_); medullary substance (_M_); fibrous coat (_c_); sending trabeculæ -(_tr_) into the substance of the gland, where they branch, and in the -medullary part form a reticulum; the trabeculæ are surrounded by the -lymph path or sinus (_l. s._), which separates them from the adenoid -tissue (_l. h._). (Sharpey.)] - -The _lymphatic vessels_ have delicate, transparent walls, with three -coats like the arteries, though much thinner, and anastomose even -more freely than the veins. They have a beaded appearance due to -the presence of numerous valves, which form constrictions on their -surface. The right lymphatic duct, which is only about an inch long, -drains all the lymphatics of the right half of the upper part of the -trunk, the head, and the neck approximately, while the thoracic duct -drains those of the rest of the body. The latter, which is the largest -vessel of the system, begins opposite the second lumbar vertebra -with a bulb-like reservoir for the lymph or chyle, the receptaculum -chyli, and extends up along the spinal column for a distance of -about eighteen inches to the seventh cervical vertebra, where, with -the right lymphatic duct, it empties into the left subclavian vein -at its junction with the internal jugular, thus establishing direct -communication between the lymph spaces and the venous system. The -orifices of both vessels are guarded by semilunar valves to prevent -regurgitation of the blood. - -[Illustration: FIG. 9.--Central (superficial) lymphatic glands of the -axilla. (After Leaf.)] - -The _lymphatic glands_ are small oval glandular bodies and occur here -and there along the course of the lymphatics. Before entering one of -them the vessel breaks up into several afferent vessels which form -a plexus within and then emerge again as several efferent vessels -which soon unite to form one trunk. These glands occur chiefly in the -mesentery, along the great vessels, and in the mediastinum, axilla, -neck, elbow, groin, and popliteal space. - -The _lymph_ varies in character with the locality, being a little -thicker and more opalescent in the lacteals, as the lymphatics of the -small intestine are called, especially during digestion, when fat is -present. Here it is called chyle. Otherwise it is generally a clear, -transparent and slightly opalescent fluid, which, owing to the presence -of fibrin, clots when drawn from the body and allowed to stand. In -fact, it resembles blood plasma very closely in composition and, as it -also contains a certain number of corpuscles or leucocytes that just -correspond to the white corpuscles of the blood, it is practically -blood without the red corpuscles. These leucocytes have considerable -power of amœboid movement and are thought by some to play an important -part in the absorption of food. - -Owing to intracapillary pressure, the lymph transudes into the -lymph spaces and bathes the tissues, being carried away again by -the lymphatics. The amount of transudation is determined by the -blood pressure--the greater the pressure, the greater the amount of -transudation--and is increased by some organic action of the cells in -the walls of the vessels. In the process of transudation a certain -amount of solid matter goes through the wall of the vessel and it is -probable that certain protein elements can be carried thus from the -blood-vessels to the lymphatics, though they do not pass through the -capillary wall as readily as other substances. Some lymph is also -probably formed by the action of the tissues themselves, though the -process is not understood. - -All muscular movements, active or passive, including the respiratory -movements, tend to drive the lymph on its way by pressure, the valves -of the vessels keeping it from flowing back. Moreover, its flow is -from the capillaries to the veins or from a region of high pressure to -one of less pressure. There is probably also some contraction in the -walls of the vessels themselves, and the continual formation of lymph -helps to drive it along. If an obstruction to the circulation occurs, -however, back-pressure results and causes too great transudation. In -that event a limb becomes swollen, pale, and generally cool. It pits -on pressure, the pressure driving the lymph out and there being no -circulation to bring it back. This condition is called œdema and occurs -in liver, kidney, and heart troubles, being generally first observed at -the ankles. In ascites, hydrothorax, hydrocephalus, and pericardial and -pleural effusions the fluid corresponds to lymph in its composition and -the large amount is due to excessive formation of the fluid, which is -normally present in small quantities. - -Lymph gives the tissues substances from the blood that they need and -carries off those they do not, whether waste or substances of use to -other tissues. Because they thus absorb certain materials not needed -by the tissues and convey them to the circulation, the lymphatics have -also been called absorbents. Indeed, lymph may be spoken of as the -middleman between the blood and the tissues. - -Another function of the lymph is to lubricate. Thus, the synovial fluid -of the joints is lymph and the pleuræ and the pericardium contain lymph -or serum to reduce the friction between the adjoining surfaces as much -as possible. The brain and spinal cord do not quite fill the cavities -of the cranium and the spinal column but float on a cushion of lymph, -the cerebro-spinal fluid. When the brain, which is subject to increase -and diminution in size, increases in size, it drives the lymph out, and -when it diminishes, the lymph returns. - -The lymph glands serve as a protection to adjacent parts and when it -leaves the gland the lymph is purer and richer in leucocytes than -when it entered. In fact, they filter harmful matter from the lymph -and apparently also form white corpuscles. Normally they can with -difficulty be felt, but in disease, if the leucocytes are unable to -destroy or carry off the poison, the lymph carries it along to the -glands, which swell and become tender. If the infection is not severe -the swelling goes down and the tenderness passes after a short time, -but if it is severe, there may be suppuration and abscess formation -and the gland even perhaps be destroyed, giving its life for the -health of the part. Thus a wound in the foot, if infected, may cause -irritation and enlargement of the glands at the knee and in the groin. - -The lymphatic glands are frequently the seat of tubercular infection, -especially in the neck, and are enlarged in scarlet fever, tonsillitis, -and diphtheria. In syphilis there is general glandular enlargement, and -the glands in the groin become enlarged in all diseases of the genital -organs. In malignant growths, such as cancer, the extension of the -disease is often along the lines of the lymphatics. - -=Glands.=--Of glands in general a word might now be spoken. They are of -two kinds, excreting and secreting, and, when simple, are formed by the -folding in of a free surface, as in the case of the salivary, gastric, -and sebaceous glands, the cells at the gland becoming so modified as to -be able to perform the function of excreting or secreting. In racemose -glands the gland is broken up into many pockets. Excreting glands take -from an organ or from a part substances which have outlived their -usefulness and are to be cast out of the body, while the secreting -glands form from the blood substances that did not exist in it before, -but which are of use to the body, as the ptyalin of the saliva. A -strict line cannot, however, be drawn between the two kinds of glands, -most glands partaking more or less of both functions, though the -sebaceous and sweat glands are probably purely excreting glands and -the salivary glands are almost purely secreting. The glands, moreover, -are more or less interchangeable in their functions, that is, they -have vicarious function, and one gland can take up and do for another -what that other is for some reason unable to do. In jaundice, where -there is stoppage of the bile duct, the kidneys help out the liver by -excreting the bile. If one kidney is removed the other does work for -both, and the glands of the skin may help out the kidneys or _vice -versa_. Hemorrhage from the lungs sometimes occurs in suppression of -the menses. - -In a general way the _function of glands_ is chemical. They filter out -by osmosis, selecting the useful parts for secretion and the useless -for excretion. In the chemical action that goes on considerable energy -is given off, as is shown by the amount of pressure in the glands and -by the fact that their temperature is higher than that of the blood. -They all work in a reflex manner, being under the control of the -central nervous system. Thus, what is eaten affects the nerve terminals -in the mouth, the sensation passes to the nervous system, and an -impulse is carried by the motor nerves to the salivary glands. - -Most of the glands have ducts to convey away their secretion to other -parts of the body or to send excretions out of the body, but there are -also _ductless glands_, which, though they seem to have some important -function in the process of metabolism, are not well understood. Most -of them seem to manufacture some substance that is absorbed by the -tissues and that plays an important part in the bodily metabolism, -though nothing is secreted by them externally. They are said to have -an internal secretion, whereas the glands with ducts have an external -secretion. The liver has both forms of secretion, the bile which is -sent out and the glycogen that is stored. The ductless glands are the -thymus and thyroid glands, the suprarenal capsules, and the pituitary -body in the brain. - -=Nervous Tissue.=--Presiding over all the organs, muscles, and -blood-vessels, as the source of all action and all sensation, are the -nerves. Nervous tissue is of two kinds: 1. the gray or vesicular, which -originates impulses and receives impressions, and 2. the white or -fibrous, which conveys impressions. The gray matter consists of large -granular cells of protoplasm containing nuclei, which give off many -branches or dendrites. From the under surface there usually comes one -main branch, the axis-cylinder process. These processes sometimes give -off branches and sometimes not, but they form the nerve fibers and -carry impulses away from the nerve cells. The cells of the processes -are elongated in shape, have a nucleus, and are placed end to end, with -a definite constriction between them. - -Each axis-cylinder process is surrounded by a sheath called the -medullary sheath, while each nerve fiber consists of a central -axis-cylinder process surrounded by the white substance of Schwann -and enclosed in a sheath. A bundle of these fibers invested in a -fibro-areolar membrane called the neurilemma constitutes a nerve, and -of these the white matter is formed. The blood supply is brought by -minute vessels, the _vasa nervorum_. - -[Illustration: FIG. 10.--Longitudinal nerve fiber (diagrammatic): _a_, -Axis-cylinder; _b_, medullary sheath; _c_, neurilemma; _d_, nucleus; -_e_, node of Ranvier. (Leroy.)] - -The nerves of the cerebro-spinal system preside over animal life and -have to do with voluntary acts, while those from the sympathetic -system regulate organic life and are quite independent of the will. -Both sensory and motor nerves extend all over the body, accompanying -the arteries in a general way. The sensory nerves end on the surface -in plexuses, in end bulbs situated in the papillæ of the skin, or -in tactile corpuscles, these last occurring more especially where -there is no hair. The motor nerves end peripherally in plexuses or -by end plates. The central terminations of the motor nerves and the -terminations of sensory nerves in special organs, except where they end -in a cell, are not well understood. - -Like muscles, nerves are probably never at rest, for through them the -muscles get their tone. When a nerve acts, no heat is produced and -there is no change in the nerve afterward, as there is in muscle. -Probably nerve impulse is the transmission of physical rather than -chemical changes along the fiber, the atoms of the nerve being set -in vibration and the vibrations being transmitted along its length. -Stimulation is produced by physical injury, by chemical influence, by -electricity, by heat, and the message is always referred to the nerve -termination. Thus, if the nerve at the elbow, over the “crazy bone,” is -touched, a tingling is felt in the fingers rather than at the point of -pressure. A person who has had an arm or leg amputated will frequently -speak of his fingers or toes on that side being cold, or complain of -pain in them, because the scar below the point of amputation tightens -around the nerves and pinches them. - -It is through the nerves that people get in touch with the outer world -and that they judge of size, weight, etc. All careful adjustment of the -muscles is under the control of the nervous system. - - - - -CHAPTER II. - -THE SKIN, ITS APPENDAGES AND ITS FUNCTION. - - -The whole exterior surface of the body is covered by the skin, an -excreting and absorbing organ, which serves as a protection to the -parts beneath and is also the organ of touch. It has two layers, -a superficial and a deep. The superficial layer, the epidermis or -cuticle, is composed wholly of epithelial cells, of which the deepest -layer is columnar and moulded upon the papillary layer of the derma, -while the intermediate layers are more rounded and the surface ones -flat. The deepest layer also contains the skin pigment, which causes -the variation in shade between the Indian, the negro, and the white -man. Below the epidermis, which is chiefly protective, is the tough, -elastic, and flexible tissue of the derma or true skin, in which are -vested most of the activities of the skin. Its surface is covered -with papillæ, which are more numerous in the more sensitive parts. -Each papilla contains one or more capillary loops and one or more -nerve fibers, while some terminate in an oval body known as a tactile -corpuscle. Beneath the papillæ is the reticular layer, composed of -interlacing bands of fibrous tissue and containing blood-vessels, -lymphatics, and nerves, as well as unstriped muscle fibers where hair -is present. - -[Illustration: FIG. 11.--Vertical section of skin.] - -At the apertures of the body the skin stops and is replaced by _mucous -membrane_, an integument of greater delicacy but which consists -fundamentally of the same two layers, a superficial, bloodless -epithelium and a deep fibrous derma. It is continuous with the skin, -but is much redder and more sensitive and bleeds more easily. The -passages and cavities that it lines, unlike those lined by serous -membranes, communicate with the exterior of the body and are for that -reason protected against contact with foreign substances by mucus, -which is thicker and more sticky than the lymph that moistens the -endothelium found on serous surfaces. Mucous membrane is found in the -alimentary canal, the respiratory tract, and the genito-urinary tract. -In cavities, like the stomach and intestines, which are subject to -variations in capacity, it is thrown into folds or rugæ. The mucus is -secreted by small glands in the membrane. - -=Appendages of the Skin.=--The skin has various appendages. On the -dorsal surface of the last phalanges of the fingers and toes are -flattened and horny modifications of epithelium, the _nails_. They have -a root embedded in a groove of skin by which they grow in length and a -vascular matrix of derma beneath them which gives growth in thickness. -To their growth in length there seems to be no limit. - -The _hairs_ also, which occur all over the body, except on the palms -of the hands and the soles of the feet, are a modification of the -epithelium. Each hair has a bulbous root springing from an involution -in the epidermis and derma called the _hair follicle_, into which one -or two sebaceous glands empty. It is raised by involuntary muscle -fibers and grows by constant additions to the surface by which it is -attached. This growth seems, however, to be limited, and when its term -is reached the hair falls out and is replaced by another. The horny -epithelial cells that go to form the hair contain the pigment that -gives it its color. - -[Illustration: FIG. 12.--Skin and longitudinal section of hair: _a_, -Epidermis; _b_, corium; _c_, sebaceous gland; _d_, fibrous root-sheath; -_e_, glassy membrane; _f_, outer root-sheath; _g_, inner root-sheath; -_h_, expanded bulbous end of hair; _i_, papilla of hair; _j_, arrector -pili; _k_, adipose tissue. (Leroy)] - -Like the hairs, the _sebaceous glands_ are situated in all parts of -the body except the palms of the hands and the soles of the feet. They -lie in the papillary layer and empty into the hair follicles, except -occasionally, when they empty directly upon the surface of the skin. -They secrete an oily substance, _sebum_, the débris resulting from the -degeneration of the epithelial cells of the gland itself, which serves -to keep the hair glossy and the skin soft and flexible. - -The _sweat glands_, on the other hand, are more frequent on the palms -and soles and though sometimes found in the derma are usually situated -lower down in the subcutaneous cellular tissue. They are least numerous -on the back and neck. Coiled up in the lower layers of the skin, they -discharge the sweat through a spiral excretory duct upon its free -surface. - -The _sweat_ is a clear, colorless, watery fluid with a salty taste, -an alkaline reaction, and a characteristic odor that varies with -the individual. If very scanty, it may be acid in reaction. Besides -water it contains a small percentage of solids, as inorganic salts, -especially sodium chloride, fatty acids, neutral fats, and at times, -especially in some diseases of the kidneys, urea, that is, the -end-products of the metabolism of starches and fats chiefly. There -is usually also some carbon dioxide, whence the expression cutaneous -respiration. - -The sweat serves to keep the skin moist and in good condition, to -remove outworn and poisonous or irritating matters, and to regulate -the temperature. As a rule it evaporates upon reaching the surface, in -which case it is known as invisible or insensible perspiration, but if -conditions of the atmosphere are not favorable to prompt evaporation, -as when the air is damp, the skin becomes damp and there is visible -perspiration. - -Though an abundant supply of blood increases the action of the sweat -glands, they are regulated by definite secretory nerves rather than -by the vasomotor nerves. In a cold sweat the action is probably due -to some disturbance of the nerve supply without increase of the blood -supply. Ordinarily perspiring is a reflex act due to the stimulation -of the afferent cutaneous nerves, as by the application of heat, but -sometimes, as in cases of strong emotions, involuntary impulses are -sent from the brain to the spinal centers and so arouse the action -of the glands. Atropin has the power of preventing the secretion of -sweat by paralyzing the terminations of the secretory nerves, while -pilocarpin produces an opposite effect in a similar way. - -On account of these sweat glands the skin becomes next in importance -after the kidneys in the excretion of waste products. The quantity of -sweat excreted varies greatly and is hard to measure. It is influenced -by the temperature and humidity of the surrounding air, by the nature -and quantity of food and drink consumed, by the amount of exercise, -the relative activity of other organs, especially the kidneys, and by -certain mental conditions. The hotter it is, the greater the amount of -perspiration. In damp weather there may be less perspiration, but it -does not evaporate and is therefore more in evidence. - -Ordinarily man has a temperature of 98.6°. The source of this body heat -or temperature is the general body metabolism, muscular activity, and -activity of the glands, especially of the liver, which is constantly -active, the blood in the hepatic vein being warmer than that in any -other part of the body. The tissue of the brain also is said to be -warmer than the surrounding blood, and the heart and respiratory -muscles, which are in constant activity, are responsible for much of -the body heat. The amount of heat generated in the body, therefore, -varies at different times, according as a person is awake or asleep, -quiet or active. - -=Temperature Regulation.=--The temperature is regulated by variations -in the production and loss of heat, less being known of its production -than of its loss. It has been calculated that four-fifths of the energy -of the body is converted into heat, one-fifth into work. As the minimum -amount of heat produced in twenty-four hours is sufficient to raise 10 -gallons of water from 0° to boiling-point, it is evident that if there -were not some way for the escape of much of this heat the body would -become hotter and hotter and finally destroy itself. The temperature, -however, except on the surface, is uniform, heat being lost as fast -as it is produced. For, although oxidation at any point raises the -heat of the blood at the point, this heat is carried by the blood to -other parts, to which the surplus is given up, while blood cooled in -the skin goes to the hotter inward parts to cool them and be warmed -itself. In fact, heat is expended by conduction and radiation, through -respiration, perspiration, and heat given to the urine and fæces. It -is, therefore, largely, 75 to 80 per cent., carried off through the -skin and the lungs; 60 to 70 per cent. is lost by radiation to the -air and other bodies with which the body comes in contact; 20 to 30 -per cent. is lost by the evaporation of sweat, 4 to 8 per cent. by -the warming of expired air, urine and feces, and 1 to 2 per cent. -by cold food that is taken in. Radiation acts more favorably where -the surroundings are cool and the air in motion, as on a breezy day. -Conduction is carried on best where the surrounding air is cool, -especially if it is moist, for moist air is a better conductor of heat -than dry air. Evaporation is very important in hot weather or where men -work in hot air. - -Even in health the temperature may range from 98.6° to 99.5°, and a -degree or two below or above is not dangerous. When a person first -gets up in the morning his temperature is apt to be subnormal, but -after food and exercise have been taken it becomes normal and stays -so till the end of the day, when, if the person is tired, it may go -up a little. If a person is tired out, the temperature is apt to be -subnormal. There is also in the body what is called the vital tide, -which is highest afternoon and evening and lowest in the morning. - -The rate of production of heat varies greatly in different people. One -person uses a certain amount of tissue more quickly than another, that -is, he lives faster. Moreover, size makes a difference in that a small -body has more surface to its weight than a large one and so has to -produce the same amount of heat at a faster rate in order to maintain -the right temperature. Taking food increases heat, probably because -of the muscular effort needed to eat it. Muscular work is another -factor. And finally the whole matter of heat production seems to be -under the control of the nervous system. Not much is known on this -point except that there is a heat center in the medulla which plays an -important part in heat production and whose influence is seen where -the temperature shoots way up in disease just before death. It is now -thought that fever is due to a disturbance of this nervous mechanism, -though just what the disturbance is is not known. - -_Fever_ is a condition of increased bodily temperature, due to -increased production or to decreased loss of heat. As a rule, in all -fevers the metabolic changes in the body are increased. Hence the -patient becomes emaciated in a long fever. The frequent increase in the -amount of urea during fever shows an increase in protein metabolism. -The temperature in fevers rises as high as 106° and in sunstroke -sometimes to 110°. Except in sunstroke a higher temperature than 106° -generally means death. Subnormal temperature is due to a decrease in -the bodily metabolism and so to lessened heat production. As a rule, -if the functions are all active, especially that of the sweat glands, -a person can be exposed to severe heat without the temperature being -affected, though sometimes on a hot summer day it may be up half to one -degree. The cause of heat-stroke with its high fever is unknown, but -probably it is due to some effect on the heat center in the brain. Heat -prostration is also due to prolonged exposure to heat, but is generally -accompanied by a subnormal temperature. The effect of cold, as in -freezing, is to diminish all the metabolic activities of the body. The -temperature can be artificially regulated more or less by variations of -food, varying amounts of exercise, by drugs, etc. - -=Sense of Touch.=--Before passing on to a discussion of the individual -parts, a few words might well be said of the sense of touch, since that -is general and resides largely in the skin, whose other functions have -just been described. It may be regarded as the form from which all -the other special senses have developed, certain portions of the body -having become more sensitive than others to certain vibrations, as the -eye to those of light. The internal organs probably have little sense -of touch. - -[Illustration] - -[Illustration: FIGS. 13, 14.--Meissner’s corpuscle from man; ×750. -(Böhm, Davidoff, and Huber.)] - -Touch is useful only within arm’s reach but there gives one a sense of -space that sight does not give. It is practically determined by the -_touch corpuscles_, which are found in the skin over almost the entire -body, though they are more numerous in some places than in others, -the distribution of the corpuscles determining the sensitiveness of -the skin. These touch corpuscles are protoplasmic bodies containing -nuclei, about which are entwined filaments from the cutaneous nerves. -Where the corpuscles are absent the filaments of the cutaneous nerves -themselves play an important part. The finger tips have a very delicate -sense of touch and the tip of the tongue is the most sensitive part of -the body. Hence spaces in the mouth seem larger than elsewhere. By -the transmission of sensations of touch to the brain the sensation is -localized and the tactile sensation becomes a tactile perception. - -There are three main divisions of the sense of touch: 1. sensations of -touch proper or tactile sensation; 2. sensations of temperature, and -3. sensations of pain. The temperature sense is the transmission by -the skin of sensations not so much of a certain degree of heat or cold -as of the difference between the temperature of an object and that of -the skin. The longer an object is in contact with the skin, the less -conscious the person is of it, not only because it becomes of the -same temperature, but also because he becomes accustomed to it. There -also seem to be in the skin, besides the touch corpuscles, two other -terminal organs with separate nerve fibers, the one for detecting heat, -the other cold; for there are places on the body where heat can be -detected and cold cannot, and _vice versa_. - -Sensations of pain may be merely an exaggeration of tactile sensation, -as in too hard pressure or too great heat, but there seems to be also -a sensation of pain in the skin. All organs are said to have common -sensibility to pain and any exaggeration of this sensibility causes a -sensation of pain. All the special senses require a certain amount of -judgment in the interpretation of the sensations they convey. - - - - -CHAPTER III. - -THE CRANIUM AND FACE. - - -The intelligence and all the special senses, except the sense of touch -already spoken of, are gathered together compactly in the head, where -they are carefully protected with bony tissue. Covering the brain is -the skull or cranium, which is made up of eight bones, the frontal, the -occipital, two parietal, two temporal, the sphenoid, and the ethmoid, -while the bones of the face are fourteen in number, two nasal, two -superior maxillary, two lachrymal, two malar, two palate, two inferior -turbinated, the vomer, and the inferior maxillary. For the most part -the bones are arranged in pairs, one on either side. - -=The Cranial Bones.=--The cranium or skull is especially adapted for -the protection of the brain and the bones are flat and closely fitted -to its surface. They have two layers of bone, the outer and the inner -tables, of which the outer is the thicker, and between these is a -tissue filled with blood-vessels, the _diploë_. In the infant, whose -brain has not yet attained its full size, opportunity must be left -for growth and the skull therefore consists of a number of bones with -interlocking notched edges, where growth takes place, but in the adult -it forms one solid covering of bone. - -The line where the edges of two cranial bones come together is called -a _suture_. The suture between the frontal bone and the forward edges -of the two parietal bones is called the _coronal suture_, that between -the two parietal bones at the vertex of the skull is known as the -_longitudinal_ or _sagittal suture_, and that between the occipital -bone and the back edges of the parietal bones as the _lambdoidal -suture_. - -Where the coronal and sagittal sutures meet is a membranous interval -known as the _anterior fontanelle_, while the _posterior fontanelle_ -is at the juncture of the sagittal with the lambdoidal suture. These -fontanelles--so called from the pulsations of the brain that can -be seen in them--close after birth either by the extension of the -surrounding bones or by the development in them of small bones known -as _Wormian bones_, the posterior one closing within a few months, -the anterior by the end of the second year. In rickets, however, the -anterior fontanelle remains open a long time, sometimes into the fourth -year. - -[Illustration] - -[Illustration: FIG. 15.--Cranium at birth, showing sutures and -fontanelles.] - -The =frontal bone=, as its name implies, forms the fore part of the -head or forehead. It joins the parietal bones above and the temporal -bones on either side. At the lower edge are the supra-orbital arches, -each with a supra-orbital notch or foramen on its inner margin for -the passage of the supra-orbital vessels and nerve, the nerve most -affected in neuralgia. Just above the arches on either side are the -superciliary ridges, behind which, between the two tables of the skull, -lie the frontal sinuses. On the inner surface the frontal sulcus for -the longitudinal sinus runs along the median line. - -The =parietal bones= are the side bones of the skull. They meet each -other in the sagittal suture at the median line above and join the -frontal and occipital bones at either end, while below they touch upon -the temporal bones, the temporal muscles being attached in part along -their lower surface. These muscles are inserted into the coronoid -process of the lower jaw, which they thus help to raise and to retract. - -[Illustration: FIG. 16.--Front view of the skull. (After Sobotta.)] - -The =occipital bone= is at the base of the skull and at birth consists -of four pieces. In the lower, anterior part is the foramen magnum, an -oval opening through which the spinal cord passes from the skull down -into the spinal canal. Half way between the foramen and the top of the -bone is the external occipital protuberance for the attachment of the -ligamentum nuchæ which holds the head erect. The inner side of the bone -is deeply concave and is divided by a cross-shaped grooved ridge into -four fossæ, the internal occipital protuberance being situated where -the arms of the cross meet. The occipital lobes of the cerebrum lie in -the two upper fossæ and the hemispheres of the cerebellum in the two -lower ones. In the grooves upon the ridge are the sinuses which collect -the blood from the brain. - -The occipital and frontal muscles, united by a thin aponeurosis, cover -the whole upper cranium and are known as the _occipito-frontalis -muscle_. At the back this is attached to the occipital bone, while -in front it interlaces with various face muscles. It is a powerful -muscle and raises the brows, wrinkles the forehead, and draws the scalp -forward. Long hair grows on the skin over it as a further protection -against blows upon the skull and sudden variations in temperature. - -The =temporal bones=--said to be so named because the hair over them -is the first to turn with age--are situated at the sides and base of -the skull and are in three portions: the squamous or scale-like, the -mastoid or nipple-like, and the petrous or stony portion. The squamous -is the upper portion and has projecting from its lower part the long -arched zygomatic process, which articulates with the malar bone of the -face and from which arises the _masseter muscle_, one of the chief -muscles of mastication, which has its insertion in the ramus and angle -of the lower jaw. Just above the zygomatic process the _temporal -muscle_ has its origin in part, while below is the _glenoid fossa_ for -articulation with the condyle of the lower jaw, the posterior portion -of the fossa being occupied by part of the parotid gland. - -The rough mastoid portion of the temporal bone is toward the back and -affords attachment to various muscles, of which the most important are -the occipito-frontalis and the sterno-cleido-mastoid. Within it are the -mastoid cells, which communicate with the inner ear and are lined with -mucous membrane continuous with that of the tympanum. They probably -have something to do with the hearing. In children they often become -the seat of inflammation (mastoid abscess) in infectious diseases and -the mastoid bone has to be cut to let out pus that has collected. -As the lateral sinus is directly behind the mastoid bone, there is -very great danger of going through into the sinus and causing a fatal -hemorrhage. - -[Illustration: FIG. 17.--Side view of the skull. (After Sobotta.)] - -The petrous portion, which contains the organ of hearing, is between -and somewhat behind the other two portions, at the lower edge of the -temporal bone, wedged between the sphenoid and the occipital bones. On -its outer surface is the _external auditory meatus_, and from below -projects a long sharp spine called the _styloid process_, to which -several minor muscles are attached. In the same angle between the -petrous and squamous portions lies the bony Eustachian tube. - -The =sphenoid= or =wedge bone=, so called because in the process of -development it serves as a wedge, lies at the base of the cranium, -forming as it were the anterior part of the floor of the cavity -containing the brain. It is a large, bat-shaped bone and articulates -with all the cranial and many of the facial bones, binding them all -together. It has a body, two large wings, and two lesser wings and, -appears on the outside of the skull between the frontal and the -temporal bones behind the zygomatic process. In the adult the body of -the sphenoid is hollowed out into the sphenoid sinuses, in which pus -sometimes forms. - -=The Ethmoid Bone.=--In front of and below the sphenoid and extending -forward to the frontal bone is the ethmoid, the last of the cranial -bones. It consists of a horizontal cribriform or sieve-like plate, from -either side of which depend lateral masses of ethmoid cells. To the -inner side of these masses are attached the thin curved _turbinated -bones_, superior and middle, while between them is a vertical plate -that forms the bony septum of the nose. Rising from the upper surface -of the cribriform plate is another vertical plate, the _crista galli_, -with the olfactory grooves on either side for the reception of the -olfactory bulbs, filaments of the olfactory nerve passing down through -the perforations of the cribriform plate to the nose. For the brain, -which fills almost the entire cavity of the cranium, is supported -by the sphenoid and ethmoid bones internally, as it is protected -externally by the other cranial bones. - -=Ossification of Sutures.=--If premature ossification of all the -sutures occurs, _idiocy_ results, while in _cephalocele_ there is a gap -in the ossifying of the bones so that the membranes or brain protrude. -In _rickets_ the forehead is high and square and the face bones -poorly developed, so that the head looks larger than it really is. In -_Paget’s disease_ the bones enlarge and soften. This affects the head -but not the face and often the first thing noticed is that the hat is -too small. _Craniotabes_ is thinning of the bone in places, the bone -becoming like parchment and being easily bent. It is generally caused -by pressure of the pillow or the nurse’s arm. - -=Bones of the Face.=--The facial bones serve to form the various -features of the face, which after all are merely organs of special -sense. Many delicate muscles control the facial expression which, -consciously or unconsciously, reflects the character of their owner. - -Surgically the most important of the facial bones are the two _superior -maxillary bones_, because of the number of diseases to which they -are liable. They meet in front, together forming the upper jaw, and -with the malar bone help form the lower part of the orbit of the eye. -They are cuboid in shape and are hollowed out into a pyramidal cavity -called the _antrum of Highmore_, which opens by a small orifice into -the middle nasal meatus and which sometimes becomes infected and has -to be tapped. The nasal process for articulation with the frontal and -nasal bones has, at its lower edge, a crest for the inferior turbinated -bone, and close beside this on the inside, extending down from the -upper edge, is a deep groove which, with the lachrymal and inferior -turbinated bones, helps to form the lachrymal canal for the nasal tear -duct. The bones give attachment to many small muscles, connected for -the most part with the nose and mouth, of which the masseter is the -only important one. - -The two _malar_ or _cheek bones_ are small quadrangular bones, which -form the prominences of the cheeks and help form the orbits of the -eyes. Projecting backward from each is a zygomatic process for -articulation with the zygomatic process of the temporal bone, while a -maxillary process extends downward for articulation with the superior -maxillary. Here again the most important muscle attached is the -masseter. If the malar bone is crushed great deformity results. - -The _lachrymal bones_ are two small bones, about the size and shape of -a finger-nail, situated at the front of the inner wall of the orbit. At -the external edge is a groove which lodges the lachrymal sac above and -forms part of the lachrymal canal below. - -The two _palate bones_ are at the back of the nasal fossæ and help to -form the floor of the nose, the roof of the mouth, and the orbit. Each -has a vertical and a horizontal plate, and it is these last that by -their juncture form the _hard palate_. Oftentimes in cases of hare-lip -_cleft palate_ also occurs, the result of incomplete development. To -remedy the consequent opening in the roof of the mouth, which makes -articulation difficult, operation is generally resorted to, though -sometimes a plate is fitted over the opening by a dentist. - -The _nasal bones_ are two small oblong bones which articulate with the -frontal and superior maxillary bones and with each other. They form the -bridge of the nose, the rest of the nose being wholly of cartilage, -except for the _vomer_, a bone shaped like a plough-share, which forms -part of the nasal septum, articulating along its anterior edge with the -ethmoid and the triangular cartilage. - -The two _inferior turbinated bones_ lie along the outer walls of the -nasal fossæ. They are thin scroll-like bones covered with mucous -membrane and serve to heat the air as it passes in. Sometimes when one -has a cold, the membrane and the bone too swell up and close the nares. -Loss of the sense of smell in a bad cold may be due to such swelling -and the consequent impeding of the entrance of odoriferous particles--a -condition that would likewise interfere with the sense of taste. Part -of the bone is sometimes removed, to enlarge the passage, enough being -left to warm the air. - -Lastly, there is the _inferior maxillary bone_ or _lower jaw_. This -has a horseshoe-shaped body and two _rami_, one at either end. Each -ramus has a pointed process in front called the _coronoid process_, -into which is inserted the temporal muscle. At the back, and separated -from the coronoid process by the sigmoid notch, is the _condyle_, which -articulates with the glenoid fossa on the temporal bone. The rami also -give attachment to the masseter muscle at its point of insertion. In -adult age the ramus is almost vertical but in old age the portion of -the jaw hollowed out into alveoli for the teeth becomes absorbed and -the angle of the jaw becomes very obtuse. On the inner side of the jaw -near the middle on either side is the fossa for the _sublingual gland_, -while the _submaxillary gland_ lies in a fossa farther back on either -side. - -Sometimes the lower jaw is dislocated and when once this has occurred -it is liable to occur again, the ligaments becoming stretched. - - - - -CHAPTER IV. - -THE ORGANS OF SPECIAL SENSE. - - -=The Nose.=--The nose, the organ of the sense of smell, is composed -of a framework of bones and cartilages, the bridge being formed by -the two nasal bones, and the septum by the vomer and the triangular -cartilage. It consists of two parts, the _external nose_ and the -internal or _nasal fossæ_, which open to the face by the anterior nares -or nostrils and into the pharynx by the posterior nares. Externally it -is covered with skin, internally with ciliated mucous membrane. The -_fossæ_ have the inferior turbinated bones along their outer walls and -are divided into three parts known as the _superior_, the _middle_, and -the _inferior meatus_, the middle one connecting with the antrum of -Highmore, while into the inferior meatus the lachrymal canal empties. -There are many small muscles of which little use is made, although in -forced respiration, as in pneumonia, where every aid to breathing is -called into play, even the alæ nasi or nostrils are made to exert what -muscular power they possess in order to supply more air. - -[Illustration: FIG. 18.--The nasal cavity. (After Sobotta.)] - -Not only is most of the air breathed in through the nose and warmed in -its passage through, but the nose is the organ of smell and by means -of the peculiar property of its nerves protects the lungs against -deleterious gases and helps the taste discriminate. The _olfactory_ -or _first cranial nerves_, after emerging from the brain, lie on the -under surface of the frontal lobe and rest on the ethmoid bone in what -is known as the _olfactory tract_. Each nerve ends in a bulb-like -termination called an _olfactory bulb_, which rests on the cribriform -plate and sends little terminal fibers down through to be distributed -to the nasal cavities, especially to the upper half of the septum of -the nose, the roof of the nose, and the anterior and middle turbinated -bones. For in the mucous membrane of the upper nasal cavity are -specially modified epithelial cells called _olfactory cells_, which -play an important part in the conduction of smell. Hence when one -wishes to smell anything especially well he sniffs it up. - -Probably the _sensation of smell_ is caused by odoriferous particles -in the atmosphere being breathed into the nose, where they affect the -olfactory cells, which transmit the impulses to the olfactory nerve -and so to the brain. Whereas a certain amount of moisture in the nasal -cavity seems to be essential for accuracy of smell, the presence of -too much or too little interferes with it. The mucous membrane has a -certain power also of distinguishing different smells at the same time, -though this power varies greatly in different people, one smell often -wholly overpowering all others. - -The cartilage below the bridge of the nose is sometimes attacked -in _syphilis_ and _cancer_, and _lupus_ often begins on the nose. -_Deviation of the septum_ may occlude all air from one side of the -nose, an effect also produced by _polypi_, generally of the turbinated -bone. Either condition is easily remedied. _Nosebleed_, though -generally unimportant, may be serious in adults. - -=The Mouth.=--The mouth is of great importance as an entrance for fresh -air to the lungs when the nasal passages are for any reason impeded -and as the resonant chamber from which proceeds the voice, man’s -chief means of communication with his fellows. Its chief value may be -said, however, to reside in the fact that it is the vestibule of the -alimentary canal. It is an ovoid cavity lined with mucous membrane and -is bounded in front by the _lips_, at the sides by the _cheeks_, below -by the floor and tongue, and above by the _hard palate_ anteriorly and -by the _soft palate_ posteriorly, the _uvula_ depending from the latter -like a curtain between the mouth and the pharynx. Shape is given to the -mouth by the bones of the upper and lower jaw and its size is altered -by the lowering and raising of the latter, which is quite freely -movable. - -[Illustration: FIG. 19.--The hyoid bone. (Toldt.)] - -At the back of the mouth, at the entrance to the pharynx, are the -_anterior_ and _posterior pillars_ of the fauces, which contain -muscular tissue, and between which on either side are thick masses -of lymphoid tissue, the _tonsils_. The floor of the mouth is formed -largely by the _tongue_, which completely fills the space within the -lower teeth. Its base or root is directed backward and downward and is -attached by muscles to the hyoid bone and the lower jaw, the _hyoid -bone_ being a horseshoe-shaped bone lying just below and as it were -within the inferior maxillary. The base of the tongue is attached also -to the epiglottis and at the sides to the soft palate by the anterior -pillars. Except at its base and the posterior part of its under surface -the tongue is free, but a fold of mucous membrane, the _frenum_, holds -it somewhat in front. Thus it possesses great versatility of motion and -serves as an auxiliary in articulation, mastication, and deglutition. - -=The Teeth.=--Securely embedded in either jaw are the teeth, nature’s -instrument for the first preparation of the food for digestion through -tearing and grinding. The _incisors_, which are in front, have wide -sharp edges for cutting the food. Next come the _canine_ teeth with a -sharp point for tearing it, while at the back are the _molars_ with a -broad flat top for grinding. - -There are two sets of teeth: 1. the _temporary_ or _milk teeth_, -twenty in number--four incisors, two canines, and four molars in -each jaw--which appear at from six months to two years, and 2. the -_permanent teeth_, thirty-two in number--four incisors, two canines, -known as _eye teeth_ in the upper jaw and as _stomach teeth_ in the -lower jaw, four bicuspids, so called because they have two cusps where -the molars have four or five, and six molars in each jaw--which come -from the sixth to the twenty-first years. The first to appear are the -two lower middle incisors, which come at the age of six months. The -last to appear are the _wisdom teeth_, the farthest back of the molars, -which come at the age of twenty-one years or thereabouts. - -Each tooth consists of a crown or body above the gum, a neck, and a -fang or root within the gum. The body is of dentine or ivory with a -thin crust of enamel and contains the _pulp_, a vascular connective -tissue containing many nerves. Beginning at the neck and covering the -fang is a layer of cement or true bone. - -=The Sense of Taste.=--The sense of taste lies chiefly in the _taste -buds_ as they are called which are filled with _gustatory cells_ -and are found in the papillæ of the tongue, principally in the -_circumvallate papillæ_ at the back of the tongue, which are few in -number and arranged in a V-shape. There is also a certain power of -taste in the tip and sides of the tongue but little in the upper -surface or dorsum. Only five special tastes can be distinguished: -bitter, sweet, acid, sour, and salt, but sometimes more than one -can be distinguished at a time, as bitter and sweet. Every one can -distinguish between different tastes but the power varies in different -people and with different conditions. Certain tastes seem to be better -distinguished in certain places, as sweet at the tip and bitter at the -back of the tongue. Moreover, the sense of taste is very dependent -upon the sense of smell, especially in the case of aromatic and savory -substances, which one really does not taste but smell. If one held his -nose and closed his eyes he would not know from the taste whether he -was eating onion or apple. This leads to the habit of pinching the nose -when taking nauseous medicines. - -To be tasted a substance must be in solution. Friction against the -tongue, lips or cheek increase the sense of taste. A temperature of -100° Fahrenheit favors taste, while both great heat and great cold -impair it. - -There are probably at least two nerves of taste, the lingual branch -of the trifacial or fifth cranial and the gustatory branch of the -glosso-pharyngeal. - -Along with the sense of taste there are other senses in the mouth which -play an important part, such as _pressure_ and the _sense of heat and -cold_, and it is often hard to distinguish them from the pure sensation -of taste, which indeed is always accompanied by them. - -=Salivary Glands.=--On either side of the mouth are three racemose -glands for the secretion of the _saliva_, which serves to soften and -lubricate the food and partially to digest starches by means of its -ferment, _ptyalin_. The _parotid gland_ is the largest and is below and -in front of the ear, opening by _Stensen’s duct_. The _submaxillary -gland_ is below the jaw toward the back on either side and its duct -is _Wharton’s duct_. The _sublingual gland_ lies beneath the mucous -membrane of the floor of the mouth and opens by eight to twenty tiny -ducts beside the frenum, the _ducts of Rivinus_. The activity of the -glands depends upon the blood supply; the more blood the greater their -activity. - -[Illustration: FIG. 20.--Dissection of the side of the face, showing -the salivary glands: _a_, Sublingual gland; _b_, submaxillary gland, -with its duct opening on the floor of the mouth beneath the tongue at -_d_; _c_, parotid gland and its duct, which opens on the inner side of -the cheek. (After Yeo.)] - -=The Tonsils.=--The tonsils vary in size and in _tonsillitis_ swell and -may even meet in the median line. They are frequently removed. When -they are enlarged one often gets a _third tonsil_ or _adenoids_, a -lymphoid growth at the back of the pharynx which causes mouth-breathing -by day and snoring by night. A child with adenoids is starved for air -and what air is breathed in is not warmed. The growth should be removed. - -A short frenum produces _tongue-tie_, which may be remedied by -snipping. Cancer of the tongue is fairly common and necessitates -a radical operation. In mumps the parotid glands are inflamed and -enlarged. - -=The Ear.=--The special organ of hearing is the ear, to which there are -three parts, the external, the middle, and the internal ear. - -The _external ear_ consists of the _pinna_ or expanded cartilaginous -portion, for the concentration and direction of sound waves, and the -_external auditory canal_, partly cartilage, partly bone, which is -directed forward, inward, and downward and conveys sound to the middle -ear. - -[Illustration: FIG. 21.--The small bones of the ear; external view -(enlarged). (After Gray.)] - -The _middle ear_ or _tympanum_ is an irregular cavity in the petrous -portion of the temporal bone. Its outer wall is formed by the _membrana -tympani_ or _drum_, an oval translucent membrane placed obliquely at -the bottom of the external auditory canal. The middle ear communicates -with the inner ear through the _fenestra ovalis_ or oval window and -contains the _ossicles_, the _malleus_ or hammer, the _incus_ or anvil, -and the _stapes_ or stirrup, which are arranged in a movable chain from -the drum to the oval window. The _malleus_, which is connected with -the membrana tympani, articulates by its head with the body of the -incus, while the stapes articulates with the _incus_ by its head and is -connected by its base with the margin of the oval window. Connection -is made between the middle ear and the pharynx and the pressure of the -air upon the drum made equal on either side by means of the _Eustachian -tubes_. These tubes are about an inch and a half long, have cilia, and -convey wax and other matter from the ear to the pharynx. Occasionally -in a cold or for some other reason they become stopped up and trouble -results in the middle ear. Some of the _mastoid cells_ also connect -with the middle ear and may become infected, causing mastoid disease. - -[Illustration: FIG. 22.--Interior view of left bony labyrinth after -removal of the superior and external walls: 1, 2, 3, the superior, -posterior, and external or horizontal semicircular canals; 4, fovea -hemi-elliptica; 5, fovea hemispherica; 6, common opening of the -superior and posterior semicircular canals; 7, opening of the aqueduct -of the vestibule; 8, opening of the aqueduct of the cochlea; 9, the -scala vestibuli; 10, scala tympani; the lamina spiralis separating 9 -and 10. (From Quain, after Sömmerring.)] - -The _internal ear_ consists of various chambers hollowed out in -the petrous portion of the temporal bone. There is an _osseous -labyrinth_, consisting of a central cavity known as the _vestibule_, -three semicircular canals, and the _cochlea_, and within the osseous -labyrinth, surrounded by _perilymph_, is the _membranous labyrinth_, -of like form, filled with the _endolymph_. Communication exists -externally with the middle ear by the _round_ and _oval windows_ and -internally with the _internal auditory canal_, through which passes -the eighth cranial or auditory nerve, the special nerve of hearing, -which is distributed to the inner ear only. When the auditory nerve -enters the ear through this internal auditory meatus it divides into -two branches, of which one goes to the vestibule and the other to the -_organ of Corti_, a group of specially modified epithelial cells in -the cochlea of the membranous labyrinth, which is very important in -transmitting the impulses to the brain. The nerve also breaks up into -very small branches and is distributed practically throughout the wall -of the labyrinth. - -The _sensation of hearing_ is the result of impulses transmitted to the -auditory nerve and so conveyed to the auditory center in the brain. -It is caused by sound waves which travel through the air from their -point of origin and enter the external ear. This collects and selects -the waves of sound and helps one to a certain extent to determine the -direction from which the sound comes. As they pass through the external -meatus the sound waves are collected into a comparatively small area -for transmission to the middle ear, where, by means of the drum, they -set in vibration the chain of ossicles. Through these the vibrations -are in turn transmitted to the oval window, being intensified in the -process. Here again they are taken up by the perilymph, from which they -pass through the wall of the membranous labyrinth to the endolymph, -affecting the epithelial lining of the labyrinth in such a way that the -impulses are transmitted to the auditory nerve, more particularly in -the vestibule, from which the vibrations enter the cochlea. They also -affect the cells of the organ of Corti in like manner as they pass from -the perilymph to the endolymph. The membrane that covers the fenestra -rotunda or round window relaxes and expands as the vibrations strike -it, thus serving to eliminate the shock of impact. - -_Musical sounds_ are caused by rhythmical or regularly repeated -vibrations, while irregular vibrations give rise to noises. In -musical sounds loudness is determined by the height or amplitude of -the vibrations, pitch by the length of the wave, and quality by the -number of so called partial tones. A sensation of sound cannot be -produced by less than 30 vibrations a second and the ordinary person -cannot hear more than 16,000 vibrations a second. Different sounds -can be distinguished when they follow each other as closely as by one -one-hundredth of a second. - -All sound does not come through the canal of the ear. The bones of the -head vibrate and carry sound. So there are instruments for the deaf -which are put in the ear and others which are placed between the teeth. - -The _semicircular canals_ are not essential to hearing but have -something to do with a person’s power of maintaining his equilibrium. -Injury to them may cause dizziness and loss of equilibrium. - -=The Eye.=--One more feature, perhaps the most expressive, remains to -be described, the eye. The senses are all modifications of the original -cutaneous sensibility and the nerve of sight is no more sensitive to -light than any other nerve. It therefore needs an end organ that is -sensitive to the motions of the ether in order to give impressions of -light. This organ is provided in the eye, which is not only itself -capable of being moved in every direction, but is placed in the most -movable part of the body, the head, which can be turned in almost a -complete circle. The _eyeball_ is spherical and lies in the cavity of -the orbit upon a cushion of fat, where it has a large range of sight -but is securely protected from injury by its bony surroundings. The -sunken eyes following protracted illness are due to the using by the -system of the fat on which the eyeball ordinarily rests. - -Each _orbital cavity_ is formed by the juncture of some seven bones and -communicates with the cavity of the brain through the _optic foramen_ -and through the sphenoidal fissure. Above the orbits are arched -eminences of skin, the _eye-brows_, from which several rows of short -hairs grow longitudinally and which serve to protect the eyes and to -limit the amount of light to a certain extent, as in frowning. - -Still further protection is afforded by the _eyelids_, longitudinal -folds of skin, the one above, the other below, which close like -curtains over the eye. Beneath the external layer of skin in the lids -is fatty tissue and then the orbicularis palpebrarum muscle by means -of which they are closed. They are kept in shape by the tarsal plates -or cartilages, in whose ocular surface are embedded the _Meibomian -glands_, whose secretion prevents the free edges of the lids from -sticking together. Along these edges grows a double or triple row -of stiff hairs, the _eye-lashes_, which curve outward so as not to -interfere with each other and also to prevent the entrance into the eye -of foreign bodies. Lining the inner surface of the lids and reflected -thence over the anterior surface of the sclerotic coat of the eye is -a mucous membrane, the _conjunctiva_, which is thick, opaque, and -vascular on the lids but thin and transparent on the eyeball. The -angles between the lids are known as the _internal_ and the _external -canthus_. - -[Illustration: FIG. 23.--The external ocular muscles. (Pyle.)] - -_Muscles_ and _Nerves_.--The eyeball is held in position by the ocular -muscles, the conjunctiva, and the lids, while surrounding it, yet -allowing free movement, is a thin membranous sac, the _tunica vaginalis -oculi_. The superior and inferior recti muscles at the upper and lower -edges of the ball turn the eye up and down; the internal and external -recti at the inner and outer edges turn the eye inward and outward; and -the superior and inferior oblique rotate the eye. The nerves supplying -these muscles are the third or motor oculi, the fourth and the sixth. - -The _lachrymal gland_, which is about the size and shape of an almond, -is situated at the upper and outer part of the orbit. It secretes a -fluid which keeps the anterior surface of the eye bathed in moisture -and is ordinarily drained away through the lachrymal sac in the inner -canthus, whence it passes by the lachrymal ducts into the nose. When -the amount secreted is excessive, it overflows the lower lid as _tears_. - -[Illustration: FIG. 24.--Diagram of the lacrimal apparatus. (Pyle.)] - -_Coats of Eye._--The membranes or coats of the eye are three in number: -an outer or sclerotic, a middle or vascular, and an inner or sensitive. - -The _sclerotic coat_ is a rather thick, fibrous, protective membrane. -Where it passes in front of the iris, however, it is thinner and -transparent and is known as the _cornea_. The cornea projects somewhat -and, as it were, resembles a segment of a smaller sphere set into the -rest of the sclerotic. - -The middle or vascular coat, known as the _choroid_, carries -blood-vessels for the retina or sensitive coat in its inner layer -and has an outer layer of pigment cells that excludes light and -darkens the inner chamber of the eye. The folds of the choroid at its -anterior margin contain the ciliary muscles and are known as the -_ciliary processes_, while the name _iris_ is given to the little -round pigmented, perforated, curtain-like muscle just in front of the -crystalline lens. The posterior surface of the iris is covered with a -thick layer of pigment cells to prevent the entrance of light except -through the central opening or _pupil_, and its anterior surface also -has pigment cells that give it its color, though the difference in the -color of people’s eyes is due rather to the amount of pigment present -than to its color, a small amount of pigment being present in blue eyes -and a large amount in brown and black eyes. Variations in the size -of the pupil are brought about by contractions of the circular and -radiating fibers of the iris, contraction of the circular fibers making -it smaller and those of the radiating larger. The pupil is constricted -for near objects and during sleep, and is dilated for distant objects. -In a dull light also it dilates to let in more light, and in a bright -light it contracts. The appearance of the pupil is often important as a -means of diagnosis and in etherization. - -[Illustration: FIG. 25.--Vertical section through the eyeball and -eyelids. (Pyle.)] - -Lastly there is the innermost _sensitive coat_ or _retina_, which has -eight layers, the outer one containing some pigment cells and the -next the rods and cones, in which the power of perception is supposed -to lie, branches of the optic nerve being distributed over it in all -directions. In fact, the retina is formed by a membranous expansion of -the optic or second cranial nerve, the special nerve of sight, which -passes into the orbit through the optic foramen at the back and enters -the eyeball close to the _macula lutea_ or _yellow spot_. The exact -spot where the optic nerve enters the retina is not sensitive and is -known as the _blind spot_. In the center of the macula lutea, however, -which is in the middle of the retina posteriorly, is a tiny pit, the -_fovea centralis_, in which all the layers of the retina except the -rods and cones are absent, and at this point vision is most perfect. -It is, therefore, always turned toward the object looked at, and when -one wishes to see an object distinctly, he must keep moving his eyes -over it that the rays from each part may fall in turn upon the fovea -centralis. - -Directly behind the pupil is the _crystalline lens_, a rather firm -gelatinous body enclosed in a capsule, which is transparent in life -but opaque in death. The lens is doubly convex and is held in place -by the suspensory ligaments, which arise from the ciliary processes. -In front of it is the anterior chamber of the eye, filled with a thin -watery fluid called the _aqueous humor_, while the larger space back of -it, occupying about four-fifths of the entire globe, is filled with a -jelly-like substance known as the _vitreous humor_. - -The chief artery of the eye is the _ophthalmic_. - -_Light Rays._--The eye is practically a camera and its principal -function is to reflect images. Although there are several refracting -surfaces and media, for practical purposes the cornea alone need be -considered. Except for those rays which enter the eye perpendicularly -to the cornea, whose line of entrance is called the _optic axis_, all -rays are refracted when they enter the eye and the point at which they -meet and cross each other behind the cornea is called the _principal -focus of the eye_. To focus properly, all the rays from any one point -on an object must meet again in a common point upon the retina, their -_conjugate focus_. In the normal eye all the rays from an object are -focused on the retina and form upon it an image of the object which, as -in the camera, is inverted, because of the crossing of the rays behind -the cornea. Once focused on the retina the light traverses the various -layers to the layer of rods and cones, where chemical action takes -place and affects the little filaments of the optic nerve, by which the -message is carried to the brain. - -[Illustration: FIG. 26.--Diagram showing the difference between (_A_) -emmetropic, (_B_) myopic and (_C_) hypermetropic eyes. (American -Text-book of Physiology.)] - -When the eye is at rest the pupil and lens are in their normal -condition and at such times the eye sees only distant objects. The -ability of the eye to focus upon objects at different distances is -called _accommodation_ and to accomplish it three things are necessary: -1. change in the shape of the lens; 2. convergence of the axes of the -eyes, and 3. narrowing of the pupils. - -When the eye is directed toward distant objects, the muscle fibers -in the ciliary processes relax, causing tightening of the suspensory -ligaments and consequent flattening of the surface of the lens. -Otherwise an image would be formed in front of the retina; for the -greater the convexity of the lens, the greater the angle of refraction. -Such accommodation is passive and so not fatiguing. To look at nearby -objects, on the contrary, the ciliary muscles contract, drawing the -choroid forward and allowing the suspensory ligaments to relax, so that -the lens bulges in front. This is an exertion. - -In order to accommodate properly, moreover, both eyes must work -together and the axes of both eyes must be directed toward the object. -Therefore, in looking at nearby objects the axes of the eyes converge, -drawn by the internal recti muscles. In _strabismus_ or _cross eye_, -where the axes of both eyes cannot be directed toward the object at the -same time, the rays fall upon one part of one eye and upon a different -part of the other eye and two separate images are seen. - -Finally there is concentric narrowing of the pupil by contraction of -the circular fibers of the iris, by which means various side rays that -would come to a focus outside the retina are excluded. - -All the muscles of accommodation, the ciliary muscles, the internal -recti, and the sphincter pupillæ, are under the control of the third -nerve. - -Connected with this power of accommodation and dependent on it are the -two conditions of _near-sightedness_ or _myopia_ and _far-sightedness_ -or _hypermetropia_. - -The normal eye is emmetropic and is almost perfectly spherical, but -in the near-sighted or myopic eye the ball, instead of being round, -is flattened from above down and so bulges in front. Consequently, -owing to the greater distance from the lens to the retina, images are -formed in front of the retina. Only nearby objects can be seen clearly, -because the farther the object from the eye the farther in front of -the retina the image is formed. Concave glasses are worn to enable -near-sighted people to see at a distance. Hypermetropic or far-sighted -eyes are flattened from before backward and can see only objects at a -distance clearly, as those nearby form images behind the retina. For -such eyes convex glasses are worn. - -As the ordinary person approaches middle life, he becomes able to see -better at a distance than near to. This _presbyopia_, as it is called, -which is practically far-sightedness, is due to a partial loss of the -power of accommodation in the lens, the result of a general loss of -elasticity in the parts. - -Another very common defect is _astigmatism_, a failure of the rays to -focus upon a point, owing generally to a flattening in the surface of -the cornea. - -_Color perception_ is also an important function of the eye. The waves -of hyperluminous ether when of a certain rate of vibration give the -sensation of heat and when their vibrations are more rapid they give -the sensation of light. Each of the primary colors of the spectrum -gives off a pretty definite number of light rays which travel through -the air and enter the eye, the number of rays determining the color -thrown upon the retina and the velocity determining the intensity of -the color. Occasionally when light is passing through into the eye it -is broken up as in a prism and the person gets a sensation as of all -sorts of colors, _chromatic aberration_. Total or partial absence of -sensitiveness to color is called _color blindness_. It is commonest -in the form of inability to distinguish between red and green and is -probably due to a defect in the retina. - -Sometimes a hair follicle on the lid becomes infected and a _sty_ -is formed. _Pink eye_ is conjunctivitis or inflammation of the -conjunctiva. A Meibomian duct may become stopped and cause bulging, or -there may be a sagging down or _ptosis of the upper lid_ in certain -diseases, as meningitis, apoplexy, and more especially syphilis. -_Rodent ulcer_ often begins by the eye or on the cheek. - - - - -CHAPTER V. - -THE NERVOUS SYSTEM. - - -The nervous system, which regulates all the vital processes of the -body, physical and chemical, and which is situated partly in the head -and partly in the trunk, may well form the connecting link between the -description of the head and that of the trunk. It has two divisions, -the cerebro-spinal system and the sympathetic system. The former -consists of the cerebrum or brain proper, the cerebellum or little -brain, the pons Varolii, the medulla oblongata, the spinal cord, and -the cranial and spinal nerves; the latter of a series of ganglia or -aggregations of nerve centers. The brain, which includes the cerebrum, -cerebellum, pons, and medulla, occupies the cranium and the spinal cord -is contained within the bony framework of the spinal column. In the -male the brain weighs about 49 ounces and in the female 44, while in an -idiot it seldom weighs more than 23 ounces. - -The =cerebrum= or brain proper has two parts or hemispheres, roughly -oval in shape, each of which has five lobes separated by fissures, the -frontal, parietal, occipital, and temporo-sphenoidal lobes, and the -central lobe or _island of Reil_ at the base of the brain. The chief -fissures are the _longitudinal fissure_, the _fissure of Sylvius_ -at the base of the brain, and the _fissure of Rolando_ between the -frontal and parietal lobes. There are also five serous cavities -called _ventricles_, the two lateral and the third, fourth, and fifth -ventricles, of which the first two, one in either hemisphere, are the -most important. Around these cavities is the _brain substance_, which -is made up of two tissues, the white and the gray, the latter forming -the outer part of the brain to the depth of perhaps half an inch, and -the white matter forming the rest. The outer or gray part is called -the _cortex_ and is largely made up of nerve cells. It might be called -the active part of the brain. The white part consists largely of nerve -fibers which are given off from the nerve cells and are carried down -into the spinal cord. - -The surface of the brain is convoluted, the ridges being separated by -deep furrows or sulci, by which means a great extent of gray matter -is secured. The furrows contain fluid from the subarachnoid spaces -and vary in number and depth according to intelligence. While the -convolutions are not uniform in all brains, the principal ones are -constant. - -Both the brain and the spinal cord are covered by three membranes, the -dura mater, the arachnoid, and the pia mater. The _dura mater_ is dense -and fibrous and lines the interior of the skull, being firmly adherent -to it at many points. In fact, it constitutes the internal periosteum -of the cranial bones. The _arachnoid_ is a delicate serous membrane, -with two layers, lubricated to prevent friction, which divides the -space between the dura mater and the pia mater, bridging over the -convolutions and enclosing the subdural and subarachnoid spaces which -are connected with lymphatics and contain a serous secretion, the -_cerebro-spinal fluid_. This fluid forms an elastic water cushion, on -which the brain rests, and prevents concussion. The _pia mater_ is -vascular, containing blood-vessels, lymphatics, and nerves, and is -closely attached to the surface of the brain, dipping down into all the -sulci. - -At the base or under surface of the brain are some very important -structures. The _olfactory bulbs_ lie beneath the frontal lobe and -projecting back is the _olfactory tract_, through which the olfactory -nerves come from the brain. Back of the olfactory tract is the _optic -commissure_ where the optic nerves coming from the brain cross each -other. And back of the commissure again is the _optic tract_, where -the optic nerves emerge from the brain. At the base of the brain are -also the exits of the twelve cranial nerves. - -[Illustration: FIG. 27.--Base of brain. (Leidy.) 1, 2, 3, cerebrum; -4 and 5, longitudinal fissure; 6, fissure of Sylvius; 7, anterior -perforated spaces; 8, infundibulum; 9, corpora albicantia; 10, -posterior perforated space; 11, crura cerebri; 12, pons Varolii; 13, -junction of spinal cord and medulla oblongata; 14, anterior pyramid; -14ˣ, decussation of anterior pyramid; 15, olivary body; 16, restiform -body; 17, cerebellum; 19, crura cerebelli; 21, olfactory sulcus; 22, -olfactory tract; 23, olfactory bulbs; 24, optic commissure; 25, motor -oculi nerve; 26, patheticus nerve; 27, trigeminus nerve; 28, abducens -nerve; 29, facial nerve; 30, auditory nerve; 31, glosso-pharyngeal -nerve; 32, pneumogastric nerve; 33, spinal accessory nerve; 34, -hypoglossal nerve.] - -Upon entering the brain the _arteries_ run a tortuous course, the -tortuosity breaking the force of the blood stream in the small vessels -where congestion would be with difficulty relieved. The basilar artery, -which is formed by the juncture of the two vertebrals, divides into -the two posterior cerebrals, each of which joins one of the anterior -cerebrals by a posterior communicating artery. The two anterior -cerebrals also are joined by an anterior communicating artery, thus -completing the circle. The circle thus formed at the base of the brain -is called the _circle of Willis_ and provides for a good supply of -blood in event of an accident to any vessel. The blood is returned to -the general circulation through the cerebral veins and sinuses formed -by the separation of the dura mater into two layers. - -The =cerebellum= is about one-seventh the size of the cerebrum and -weighs about 5 ounces. It lies in the lower occipital fossæ of the -skull and is oblong in shape and divided into two lateral hemispheres -by a transverse fissure. It is made up of both white and gray matter, -of which the former predominates, the gray being external as in the -cerebrum. The cells are about the same as in the cortex and its surface -is traversed by queer furrows. Of its function little is known but it -probably plays a most important part in the coördination of the nervous -and muscular acts by which the movements of the body are carried on. - -At the back of the cerebrum and below the cerebellum is the =pons -Varolii=, which forms a connecting link with the medulla oblongata or -bulging part of the cord. It is made up essentially of white matter or -nerve fibers, though there is a small amount of gray matter in which -are found the nuclei of some of the cranial nerves. - -In the =medulla oblongata=, which is about 1 inch long and extends from -the pons Varolii to the upper border of the atlas or first cervical -vertebra, the gray matter is not necessarily external to the white but -is found in patches in the white. The gray matter here corresponds more -or less to that of the spinal cord and the white matter is continuous -with that of the cord. From the medulla arise the fifth to twelfth -cranial nerves and the vasomotor nerves. The cardiac nerve has its -center here and here too are the centers of respiration, phonation, -deglutition, mastication, and expression. In the medulla the nerves -that arise in the cerebrum cross over from one side of the body to -the other on the crossed pyramidal tracts. The importance of this -crossing of the nerve fibers is seen in apoplexy, when a blood-vessel -is ruptured in the brain and hemorrhage causes pressure, generally on -the motor tract. Paralysis of the nerves and of the muscles to which -they go results. The paralysis is generally of one side of the body, -the opposite side from that on which the injury occurred. The seat -of injury in the brain or cord can frequently be determined by the -situation and extent of the paralysis. - -=Spinal Cord.=--Extending down from the medulla through the spinal -column is the cord. Its length from the foramen magnum, where it -begins, down through the vertebræ to the lower border of the first -lumbar vertebra, where it ends in a very fine thread-like process with -no special function, called the _filum terminale_, is 17 to 18 inches. -Just before it ends a number of nerves are given off in a tail-like -expansion known as the _cauda equina_ or horse’s tail. It is not -uniform throughout its length but presents two enlargements, a cervical -enlargement in the lower cervical region, and a lumbar enlargement in -the lower dorsal region, where the nerves are given off to the arms and -legs respectively. The membranes are the same as those of the brain -and are continuous with them, but here the dura mater is not attached -to the bony walls enclosing it. For the cord does not fit closely -into the canal but is as it were suspended in it. The _subarachnoid -space_ communicates with the ventricles of the brain by the _foramen of -Majendie_ and is filled with _cerebro-spinal fluid_ for the protection -of the cord. In cerebro-spinal meningitis or spotted fever this fluid -is infected and for diagnosis lumbar puncture is performed. - -[Illustration: FIG. 28.--Different views of a portion of the spinal -cord from the cervical region, with the roots of the nerves. In _A_ the -anterior surface of the specimen is shown, the anterior nerve root of -its right side being divided; in _B_ a view of the right side is given; -in _C_ the upper surface is shown; in _D_ the nerve roots and ganglion -are shown from below: 1, the anterior median fissure; 2, posterior -median fissure; 3, anterior lateral depression, over which the anterior -nerve roots are seen to spread; 4, posterior lateral groove, into -which the posterior roots are seen to sink; 5, anterior roots passing -the ganglion; 5´, in _A_, the anterior root divided; 6, the posterior -roots, the fibers of which pass into the ganglion, 6; 7, the united or -compound nerve; 7´, the posterior primary branch seen in _A_ and _D_ -to be derived in part from the anterior and in part from the posterior -root. (Allen Thomson.)] - -If a cross-section of the cord is made, it is found to have a pretty -definite structure. It is roughly circular and is divided by certain -fissures, of which the most important are the anterior and posterior -median, the latter being rather a dividing line or septum. By them -it is divided into halves connected by a small band in the middle -called the _commissure_. The white matter is exterior to the gray -and is divided by it into four columns, which again are divided into -tracts according to certain groups of nerves that travel through -them. The most important tract is the direct pyramidal tract in the -anterior column. The gray matter is arranged in the form of a letter H -practically, consisting of two lateral halves, more or less crescentic -in outline, connected by a narrow band, the _gray commissure_. Each -half is divided into two _horns_, the anterior, toward the front of the -cord, and the posterior, toward the back, the former being generally -much thicker and heavier than the latter. The structure of the gray -and of the white matter is essentially the same as in the brain, -but the proportion varies in different parts of the cord, the white -predominating in the cervical region and the gray being much better -developed in the lumbar region, where the nerve cells for control of -the lower extremities occur. The gray is least well developed in the -dorsal region. Through the center of the cord runs a small hole or -canal filled with cerebro-spinal fluid, the _central canal of the cord_. - -[Illustration: FIG. 29.--Functional areas of the cerebral cortex, left -hemisphere. (A. A. Stevens.)] - -The brain is the seat of intelligence and will, the center of all -voluntary action. Molecular change in some part of the cerebral -substance is the indispensable accompaniment of every phenomenon of -consciousness. Indeed, the brain is never in a state of complete -repose, there being dreams even during sleep. The brain is not -sensitive to injury in the sense of pain. It can be lacerated without -much pain. - -Various centers exist in the brain, of which the most important perhaps -is the _motor center_. The _visual center_ is in the occipital lobe, -the _auditory center_ in the temporal lobe, the _speech center_ in the -third left frontal convolution. Thus the impulses of the senses have -been located, though the function of many parts, the so called _silent -areas_, are still in obscurity. - -The _motor center_, that is, the center for motion of the skeletal -muscles, is situated about the fissure of Rolando and is divided into -three parts, one for the legs, one for the face, and one for the arms, -the one for the legs being uppermost and the others below in the order -mentioned. Fibers from these cells extend down through the brain and -cord to the muscles, the fibers being collected into well-recognized -bundles and the whole known as the _motor tract_. There may be one long -fiber from a cell in the brain down through most of the cord or there -may be a succession of shorter fibers that are not actually connected -but are in close contact with each other. In the upper pons the fibers -for the face cross to the opposite side, while the rest keep on down -through the medulla, and as they emerge from the medulla they too cross -to the other side and keep on down in the crossed pyramidal tract. -A few fibers do not cross but come down the direct pyramidal tract, -which, however, disappears part way down. The _crossed pyramidal tract_ -is the true motor tract and in it the fibers are continually sending -branches to the cells in the gray matter, where they connect with the -anterior horn. - -The anatomy of the _sensory tract_ is not so well understood. By it -impulses are sent to the brain by the peripheral organs, practically -the surface of the body. The sensory fibers connect with the sensory -cells in the posterior horn, from which fibers are sent to the brain, -practically the reverse of motor action. There are three chief sensory -tracts, which are supposed to transmit different sensations, one pain, -one muscular sensations, and the third sensations of touch. All these -tracts, of which the chief is the _direct cerebellar tract_, in passing -up the cord pass to the opposite side at different levels and then go -on to the cortex of the brain. - -The action of the nerves is similar to reflex action, only that an -effort of will is needed to send an impulse from the brain. It is by -the help of the brain along this line that an infinity of artificial -reflexes or habits is acquired, for which volition is needed in the -beginning but which are later done unconsciously. Herein lie the -possibilities of all education. - -The brain and spinal cord work together, the cord acting as a medium -between the brain, in which all the higher psychical processes, such as -will, thought, etc., originate, and the muscular apparatus. The cord, -however, has some action entirely independent of the brain, as is seen -in _reflex action_. This action is entirely involuntary, so that the -cord is sometimes spoken of as the seat of involuntary action, commonly -called reflex action. All unconscious acts are reflex acts, as when the -hand is drawn away from a hot iron. If an impulse is sent along one -of the sensory fibers, it enters the cord through the posterior horn, -where its nerve cell is found. Then, through some connection between -the nerve cell of the sensory fiber and that of the motor fiber the -impulse is transmitted to the motor cell and another impulse is sent -out of the cord along the motor fiber of the nerve to the muscle. -One of the commonest reflexes is the _knee-jerk_. Reflex action is -important because the reflexes are interfered with, delayed, destroyed, -or increased in different diseases. The time normally required for a -reflex act is very brief, that for the knee-jerk being about three -one-hundredths of a second. - -The nerves of the head, known as the _cranial nerves_, arise from the -brain, while the rest of the body is supplied by the spinal nerves, -which come off at intervals from the spinal cord. The cranial nerves -consist of twelve pairs: (1) The olfactory or nerve of smell, (2) the -optic or nerve of sight, (3) the motor oculi, (4) the patheticus, which -controls the eye, (5) the trigeminus or trifacial, a nerve of general -sensation, motion, and taste, (6) the abducens, a motor nerve, (7) the -facial nerve of the face, ear, palate, and tongue, (8) the auditory or -nerve of hearing, (9) the glosso-pharyngeal, nerve of sensation and -taste, (10) the pneumogastric or vagus, which is both motor and sensory -and governs respiration, the heart, and the stomach, (11) the spinal -accessory, to the muscles of the soft palate, and (12) the hypoglossal, -the motor nerve to the tongue. - -The _spinal nerves_ also are arranged in pairs: Eight cervical pairs, -twelve dorsal or thoracic, five lumbar, five sacral, and one coccygeal, -these titles denoting their point of origin near the vertebra of the -same name. Each of these nerves arises by two roots, an anterior motor -root from the anterior horn of gray matter and a posterior sensory root -from the posterior horn, the latter having a ganglion upon it. After -emerging from the cord the two roots unite to form the nerve, that the -nerve may contain both motor and sensory fibers. The motor fibers are -called efferent because they carry impulses _from_ the cord, while the -sensory are called afferent because they carry impulses back _to_ the -cord. After leaving the cord the nerves unite to form plexuses, which -again divide into various nerve trunks and are distributed to the -muscles. - -The first _cervical nerves_ pass out of the spinal column above the -first cervical vertebra and the other cervical nerves below that -and the succeeding vertebræ, while the other spinal nerves emerge -each below the corresponding vertebra, as the first dorsal below -the first dorsal vertebra, etc. After emerging they break up into a -large anterior division and a small posterior division, the posterior -branches supplying the spine and the dorsal muscles and skin, the -anterior the rest of the trunk and the limbs. The _cervical plexus_ is -formed by the anterior divisions of the first four cervical nerves, the -_brachial plexus_ by the last four cervical and the first dorsal or -thoracic nerves, the _lumbar plexus_ by the four upper lumbar, and the -_sacral plexus_ by the last lumbar and the four upper sacral nerves. - -The only important branch of any of the four upper cervical nerves, -which in general supply the neck and shoulders, is the _phrenic_, which -is distributed to the pericardium, the pleuræ, and the under surface of -the diaphragm. - -The _brachial plexus_, as its name implies, supplies the arms and has -a number of important branches, as the circumflex to the shoulder, the -musculo-cutaneous to the upper arm, the elbow-joint, and the outer -surface of the forearm, the internal cutaneous to the inner side of -the arm, the median to the pronators and flexors and the fingers on -the radial side, and the ulnar to the elbow and wrist-joint. The -musculo-spiral runs down the spiral groove to the external condyle of -the humerus or upper arm bone, where it divides into the radial and the -posterior interosseous, the former going to the thumb and two adjacent -fingers and the latter to the wrist-joint and the muscles on the back -of the forearm. Sometimes, in fracture of the humerus the callus thrown -out pinches the musculo-spiral and causes pain. - -The dorsal or _thoracic nerves_ supply the back with their posterior -divisions and their anterior divisions are the _intercostal nerves_. - -The _lumbar nerves_ supply the abdomen, pelvis, and thigh, the chief -branches being the ilio-hypogastric to the abdomen and gluteal region, -the ilio-inguinal to the inguinal region and scrotum, the external -cutaneous and genito-crural to the thigh, and the obturator to the -thigh and the hip and knee-joints. The anterior crural descends beneath -Poupart’s ligament and divides into an anterior and a posterior -division which supply the thigh muscles, its branches going to the -pelvis. - -[Illustration: FIG. 30.--Diagrammatic view of the sympathetic cord -of the right side, showing its connections with the principal -cerebro-spinal nerves and the main preaortic plexuses. (Reduced from -Quain’s anatomy.)] - -The _sacral plexus_ supplies the organs of the pelvis, the thigh, and -the leg. Its chief branches are the great sciatic, the largest nerve in -the body, and the small sciatic, which go to the buttocks and thigh. -The great sciatic runs down the back of the thigh and divides at the -lower third of the thigh into the internal and external popliteal -nerves, the former of which passes along the back of the thigh to the -knee, where it becomes the posterior tibial, which in turn divides -at the ankle into the internal and external plantar. The external -popliteal descends along the outer side of the popliteal space and -divides an inch below the head of the fibula into the anterior tibial, -which supplies the flexors and skin of the ankle-joint, and the -musculo-cutaneous, which sends branches to the skin of the lower leg -and the dorsum of the foot. - -=The Sympathetic System.=--Joined to the cerebro-spinal system by -intervening cords is the sympathetic system. This is made up of two -series of ganglia, one on either side of the spinal column, connected -by longitudinal bands and extending from the base of the skull to the -coccyx. They do not form an independent nervous system, each ganglion, -which seems to resemble the motor cells of the spinal cord, being -connected by motor and sensory fibers with the cerebral system. - -The _sympathetic nerves_ are mostly gray, non-medullated fibers and -are distributed to viscera, secreting glands, and blood-vessels, whose -movements are involuntary and feelings obtuse. They form networks upon -the heart and other viscera and send branches to the cranium to the -organs of special sense. There are three main plexuses: The _solar -plexus_ behind the stomach, which supplies the abdominal viscera; the -_hypogastric plexus_ in front of the prominence of the sacrum, whose -nerves go to the pelvic organs; and the _cardiac plexus_ behind the -aortic arch for the thoracic viscera. - -Over these nerves one has no control. A blow in the region between the -costal cartilages and below the sternum is a solar plexus blow and is -very upsetting. - -The sympathetic system serves to maintain vitality in all the important -portions of the system and one of its important functions is to keep up -communication between one part and another, so that when any organ is -affected the others will act accordingly and help out to the best of -their ability. - - - - -CHAPTER VI. - -THE BACK. - - -[Illustration: FIG. 31.--The spinal column. (Church and Peterson.)] - -=The Spine.=--The trunk may be roughly divided into the back, the chest -or thorax, the abdomen, and the pelvis. By the back is denoted the -spinal column with its muscles, blood-vessels, etc., and the spinal -cord already described. The spine or vertebral column, which serves the -double purpose of holding the body erect and of protecting the cord, is -usually about two feet, two inches in length. In its course there occur -several curves, which serve to give springiness and strength and, with -the intervertebral cartilages, to mitigate the force of concussion from -blows and falls. The curve is convex forward in the cervical region, -convex backward in the dorsal, forward in the lumbar, and backward -again in the sacral region. There is most freedom of motion in the -cervical region. - -As is the case with the other bones, the _vertebræ_ are specially -adapted in shape and size to the needs they are called upon to fill. -Strength and flexibility, with a minimum bulk, a channel for the cord, -and passages for the numerous nerves and blood-vessels are some of the -requirements which, in combination, they meet to an astonishing degree. -They are thirty-three in all, and are divided into groups according -to the region in which they occur: seven cervical in the neck, twelve -dorsal or thoracic, five lumbar, five sacral, and four coccygeal. - -Although the vertebræ of the different groups differ more or less -in size and shape in accordance with the various demands of their -positions, they all have certain general characteristics. Each has -a body, two laminæ, two pedicles, two transverse processes, and one -spinous process. The _pedicles_ extend back from the body on either -side and support two broad plates of bone, the _laminæ_, whose juncture -at the back completes the _spinal foramen_ for the passage of the cord. -At their juncture is the _spinous process_, which can be felt beneath -the skin, while the _transverse processes_ project from the juncture of -the laminæ with the pedicles. All the processes are for the attachment -of muscles that move the spine. The _body_ is formed of cancellous bone -with a compact layer outside. Transversely it is slightly oval, while -its upper and lower surfaces are flat, except in the cervical region, -where the upper surface is concave laterally and the under convex -laterally and concave from before back. Between the bodies are disks of -fibro-cartilage, which increases motion and springiness. The _spinous -process_ or _spine_ is short in the cervical region, long and directed -downward in the dorsal region, thick and projecting almost straight -out in the lumbar region. The pedicles are notched above and below so -that when articulated the notches of two vertebræ join to form the -_intervertebral foramen_ for the outward passage of nerves and the -inward passage of blood-vessels. - -The distinguishing mark of the _cervical vertebræ_ is the foramen in -each transverse process, through which the vertebral arteries run to -the skull. They are also smaller than the dorsal and lumbar vertebræ. -The _dorsal vertebræ_ are distinguished by having on the transverse -processes and on the body smooth articular surfaces called facets and -demi-facets for articulation with the ribs. The _lumbar vertebræ_ are -the largest and heaviest and have the thickest spine. By the time the -sacral region is reached, however, the vertebræ have only a rudimentary -spinous process. Moreover, in adult age the sacral bones grow together -and form one triangular bone, the _sacrum_, which has a broad base -called the _promontory of the sacrum_ and a blunt apex. It is concave -in front and convex behind and has an articulating surface for joining -the pelvic bones. In the case of the _coccyx_ also the four original -bones, all rudimentary in character and supposed to be the survival of -a tail, grow together to form one bone. Together the sacrum and coccyx -form the posterior wall of the true pelvis. - -[Illustration: FIG. 32.--A type of vertebra. (Leidy.) 1, Body; -2, pedicle; 3, lamina; 4, spinal foramen; 5, spinous process; 6, -transverse process; 7, articular process.] - -[Illustration: FIG. 33.--The sacrum, from before. (Drawn by D. Gunn.)] - -Some of the dorsal vertebræ are peculiar in the arrangement of their -facets and demi-facets, while among the _cervical vertebræ_ are several -whose peculiarities should be more carefully noted. Thus, the first -cervical vertebra or _atlas_ supports the head and has practically no -body, the place of the body being taken by a narrow anterior arch of -bone and an opening, continuous with the spinal foramen, into which the -_odontoid process of the axis_ fits, being held in place by ligaments. -At either side on top is a facet for articulation with the occipital -bone. There is almost no spine. The second vertebra or _axis_ has -surmounting the body the odontoid process, with a facet in front for -articulation with the atlas and one behind for the transverse ligament -to move over. The seventh cervical vertebra or _vertebra prominens_ -has a very long spinous process--hence name--to which is attached the -_ligamentum nuchæ_. It can be felt very distinctly on the living. - -Running from the skull down through the spinal column into the sacral -vertebræ and formed by the joining of the spinal foramina of the -individual vertebræ is an opening called the _spinal canal_, which -holds the cord. The cord, however, stops practically at the first -lumbar vertebra, where it splits up into the _cauda equina_, only the -_filum terminate_ extending farther down. - -Occasionally the laminæ do not form completely and the membranes of the -cord may bulge out and form a tumor, or the cord itself may come out -also. This generally occurs in the lumbar region, where it is known as -_spina bifida_. If in case of fracture of a vertebra there is paralysis -of the parts below due simply to the pressure of a fragment of bone -upon the cord, it may be completely cured by removal of the fragment. -If, however, the cord suffers injury, the paralysis will remain. -_Humpback_ or _Pott’s disease_ is caused by the tubercle bacillus, -which eats away the bodies of the vertebræ so that the column caves in -and the spinous processes are thrown out in a hump or kyphos. - -[Illustration: FIG. 34.--Muscles of the right side of the head and -neck: 1, Frontalis; 2, superior auricular; 3, posterior auricular; 4, -orbicularis palpebrarum; 5, pyramidalis nasi; 6, compressor naris; 7, -levator labii superioris alæque nasi; 8, levator labii superioris; -9, zygomaticus major; 10, orbicularis oris; 11, depressor labii -inferioris; 12, depressor anguli oris; 13, anterior belly of digastric; -14, mylohyoid; 15, hyoglossus; 16, stylohyoid; 17, posterior belly of -digastric; 18, the masseter; 19, sternohyoid; 20, anterior belly of -omohyoid; 21, thyrohyoid; 22, 23, lower and middle constrictors of -pharynx; 24, sternomastoid; 25, 26, splenius; 27, levator scapulæ; 28, -anterior scalenus; 29, posterior belly of omohyoid; 30, middle and -posterior scalenus; 31, trapezius. (Dorland’s Dictionary.)] - -=Muscles of the Neck.=--Before speaking of the muscles of the back -a few of those of the neck had best be taken up. They are numerous -but mostly of minor importance. Largest and most important is the -_sterno-cleido-mastoid muscle_, which has its origin on the upper part -of the sternum and the inner third of the clavicle and is inserted into -the mastoid process of the temporal bone. It passes obliquely across -the side of the neck and serves to flex the head to the side and to -draw the face in the opposite direction. When both muscles contract the -head is flexed on the neck and the neck on the chest. In _wry neck_ -or _torticollis_ this muscle is constantly contracted. The _platysma -myoides_ arises from the fascia over the pectoral, deltoid, and -trapezius muscles and is inserted into the lower jaw, the angle of the -mouth, and the loose tissue in the lower part of the face. It wrinkles -the skin of the neck and depresses the lower jaw. In the cow and horse -it is so highly developed that by it the skin can be contracted all -over the body to drive off flies. The _rectus capitis anticus major_ -arises from the third to the sixth cervical vertebræ and is inserted -into the occipital bone, serving to flex the head. The _scalenus -muscles_ have their origin on the lower cervical vertebræ and are -inserted into the first and second ribs, thus aiding in the elevation -of the ribs as well as in lateral flexion of the neck. The head is -held upright by the _ligamentum nuchæ_, which rises from the external -occipital protuberance and is inserted into the spinous processes of -all the cervical vertebræ except the first. - -=Muscles of the Back.=--The chief back muscles are the trapezius -and the latissimus dorsi, which together cover in the back pretty -thoroughly. The _trapezius_ arises from the occipital bone, the -ligamentum nuchæ, and the spinous processes of the seventh cervical -and all the dorsal vertebræ and is inserted into the outer third of -the clavicle or collar bone and the acromion process and spine of the -scapula or shoulder blade. It is thus triangular in shape and covers in -the neck and shoulders, serving to draw the head back and to the side. -It overlaps the latissimus dorsi. - -The _latissimus dorsi_ has its origin by aponeurosis from the spinous -processes of the six lower dorsal and all the lumbar and sacral -vertebræ, from the crest of the ilium or hip bone, and from the three -or four lower ribs, swings across the side, dwindling in size, and is -inserted by a small tendon into the bicipital groove of the humerus or -upper arm bone, thus covering in the part of the back not covered by -the trapezius. It draws the arm down and back, raises the lower ribs, -and draws the trunk forward, as in climbing. The flat muscles of the -back and abdomen have a tendency to flatten out into aponeuroses, such -as occurs in the origin of the latissimus dorsi. - -The _levator scapulæ_, from the transverse processes of the upper -cervical vertebræ to the posterior border of the scapula, serves -to raise the angle of the scapula, and the _rhomboideus major_ and -_minor_, from the ligamentum nuchæ, the seventh cervical, and the upper -dorsal vertebræ to the root of the spine of the scapula, draw the -inferior angle back and up. - -[Illustration: FIG. 35.--Muscles of the trunk from behind (left side, -superficial; right side, deep): 1, Sternomastoid; 2, splenius; 3, -trapezius; 4, latissimus dorsi; 5, infraspinatus; 6, teres minor; -7, teres major; 8, deltoid; 9, external oblique of abdomen; 10, -gluteus medius; 11, gluteus maximus; 12, levator anguliscapulæ; 13, -rhomboideus minor; 14, rhomboideus major; 15, part of longissimus -dorsi; 16, tendons of insertion of iliocostalis; 17, supraspinatus; 18, -infraspinatus; 19, teres minor; 20, teres major; 21, serratus magnus; -22, upper, and 22´, lower part of serratus posticus inferior; 23, -internal oblique; 24, gluteus medius; 25, pyriformis and superior and -inferior gemelli; 26, 26´, portions of obturator internus; 27, tendon -of obturator internus; 28, quadratus femoris. (Dorland’s Dictionary.)] - -The _blood supply_ in the cervical region and about the shoulders comes -from branches of the subclavian artery, such as the suprascapular and -the transversalis colli. Lower down the supply comes from the posterior -branches of the intercostals, dorsal branches of the lumbar, and -branches of the internal iliac. - -The muscles of the back are supplied by the _spinal nerves_, the spinal -accessory also going to the trapezius muscle. - - - - -CHAPTER VII. - -THE CHEST. - - -The chest or thorax occupies the upper part of the trunk in front and -is a dome-shaped cavity containing and protecting the heart and lungs. -Its walls are formed by the dorsal vertebræ at the back, the ribs at -either side, and the sternum and costal cartilages in front, all well -covered with muscles. The floor is formed by the diaphragm. Through the -upper opening of the chest pass the trachea, the esophagus, and many -important vessels and nerves. - -[Illustration: FIG. 36.--Thorax (anterior view.) (Ingals.)] - -The shape of the chest may vary in disease. Thus, in rickets there is -the prominent “pigeon” breast and the rosary, that is, a bead at the -juncture of each rib with the costal cartilage, while in emphysema the -chest is enlarged in all directions and barrel-shaped. In severe cases -of lateral curvature it is distorted but may be improved by exercises. - -=The Sternum.=--The sternum or breast-bone is a long narrow bone and -has three parts, the _manubrium_ or handle above, the _gladiolus_ or -sword, and the _ensiform cartilage_ at the lower end. On either side -are notches for the costal cartilages; for the first seven ribs as -well as the clavicle articulate with it. Except for some muscles along -the edges it lies directly under the skin and the ridge between the -manubrium and the gladiolus can be felt in the living, a fact which -assists in determining the position of the different ribs in cases of -fracture, as the second rib articulates at this point. - -[Illustration: FIG. 37.--A and B, typical ribs; C, first rib; D, -twelfth rib. 1, head; 2, neck; 3, tuberosity; 4, grooved edge; 5, -shaft; 6, oval depression for costa cartilage.] - -=The Ribs.=--The ribs are twenty-four in number, twelve on each -side, of which the upper seven, which articulate with the sternum -by individual cartilages, are called _true ribs_, the other five -_false ribs_. Of the false ribs the upper three articulate indirectly -with the sternum through the seventh cartilage, with which their -cartilages unite, while the other two have their anterior extremities -free and are called _floating ribs_. All the ribs slope down toward -the front and are by nature more freely movable in women than in -men. Most of the ribs have a head divided by a little ridge into two -facets for articulation with the dorsal vertebræ, a flattened neck, -a tuberosity at the base of the neck with a facet for articulation -with the transverse process of the vertebra below, an angle, and a -shaft, which is externally convex and is grooved on its lower edge -for the intercostal vessels and nerve. The first and second, eleventh -and twelfth ribs, however, are somewhat peculiar, the first two being -shorter, flatter and rather broader than the rest and the first having -only one facet on the head, while the last two have only one facet on -the head and no neck or tuberosity. - -The _costal cartilages_ serve to prolong the ribs and greatly increase -the elasticity of the chest wall. They grow longer down to the seventh -and then decrease again in length. - -The ribs, except the first and second, which are protected by the -clavicle, are frequently _broken_. Such a break causes pain in -breathing and sometimes the end of a rib pierces the lung tissue -and swelling all over the body results, due to the presence of air. -_Caries_ or death of the rib is also frequent. _Fracture of the -sternum_ occurs occasionally, generally from direct force, as from a -blow with the knee in foot-ball, and there may be dislocation between -the manubrium and gladiolus. - -=Muscles of the Chest.=--The spaces between the ribs, from the -tubercle of the rib behind to the cartilage in front, are filled by -the _external intercostal muscles_, which pass downward and forward -from the lower border of one rib to the upper border of the one below. -There are, therefore, eleven pairs of these muscles. There are also -eleven pairs of the _internal intercostals_, which commence at the -sternum and extend back to the angle of the rib. These extend downward -and backward. The external intercostals raise and evert the ribs in -inspiration, the internal depress and invert them in expiration. - -The chief respiratory muscle, however, is the _diaphragm_, a somewhat -fan-shaped muscle that forms the floor of the chest cavity. It takes -its origin from the ensiform cartilage, the six or seven lower ribs and -their cartilages, and from the upper three or four lumbar vertebræ, -that is, from the whole of the internal circumference of the thorax, -and is inserted into the central cordiform tendon. It has several large -and several small openings for the aorta, the esophagus, the venæ cavæ, -the thoracic duct, and various nerves, and its surfaces are covered by -serous membranes, by the two pleuræ and the pericardium above and by -the peritoneum below. It partially supports the heart and lungs. Convex -toward the chest, it becomes flattened in contraction and so increases -the capacity of the chest. It aids in all expulsive acts, as sneezing, -coughing, laughing, urinating, defecating, vomiting, and childbirth. -_Hiccough_ is spasm of the diaphragm. - -[Illustration: FIG. 38.--Interior view of the diaphragm. (Leidy.) -1-3, The three lobes of the central tendon, surrounded by the fleshy -fasciculi derived from the inferior margin of the thorax; 4, 5, the -crura; 6, 7, the arcuate ligaments; 8, aortic orifice; 9, esophageal -orifice; 10, quadrate foramen; 11, psoas muscle; 12, quadrate lumbar -muscle.] - -The _arteries_ of the chest are the intercostal branches of the -subclavian and the thoracic aorta, the phrenic, mediastinal, and -intercostal branches of the internal mammary, and the thoracic branches -of the axillary. - -The _nerves_ are the intercostals and phrenics. - -=Mammary Glands.=--On the outside of the chest walls, lodged in the -fascia of the pectoral muscles, are the mammary glands, accessory -organs of the generative system. They exist in both sexes but are -only rudimentary in the male. In the female they are small before -puberty but enlarge as the generative organs become more completely -developed, forming two hemispherical eminences, one on either side, -between the third and seventh ribs. During pregnancy they increase once -more in size preparatory to the secretion of the milk, and in old age -they atrophy. From the middle projects a small pinkish-brown conical -eminence, the _nipple_, surrounded by a paler area, the _areola_. After -the second month of pregnancy both nipple and areola become darker in -color, a point of great diagnostic value in early pregnancy. - -The mammary glands themselves consist of lobules of gland tissue with -a central lactiferous tubule, the lobules being gathered into lobes -with fatty tissue between. From the juncture of these tubules result -fifteen or twenty excretory ducts, the _tubuli lactiferi_, which -converge toward the areola. Beneath the nipple they dilate, forming the -_ampullæ_, and then contract again to pass out through the nipple as -straight tubes. - -_Breast abscess_ occurs most commonly in nursing mothers, as where -a part is most active there is most danger of abscess. Many benign -_tumors_ of the breast, as the fibrous tumors, occur and are especially -common in young women. If a fibrous tumor is allowed to develop it may -become cancerous. _Cancer_, however, generally occurs after the age of -forty and is usually due to some irritation, as to a blow from a ball. - -The _arteries_ of the breasts are the thoracic branches of the -axillary, the intercostal, and the internal mammary. - -The _nerves_ are from the thoracic cutaneous. - - - - -CHAPTER VIII. - -THE HEART AND CIRCULATION. - - -=The Heart.=--Shielded within the chest are, as has been said, the -heart and lungs. The heart lies on the left side behind the sternum -and the cartilages of the fourth to seventh ribs in a closed, conical, -membranous sac, the _pericardium_, which is attached by its base to the -central tendon of the diaphragm, and whose point extends up between -the pleuræ of the lungs. This sac has an external fibrous layer and an -internal serous layer that is reflected back over the heart itself, -forming a closed sac, within which a thin fluid is secreted that serves -to reduce friction during the movements of the heart, the two inner -surfaces sliding over each other with every beat. - -[Illustration: FIG. 39.--The heart. (Stoney.)] - -[Illustration: FIG. 40.--Left auricle and ventricle, opened and part of -their walls removed to show their cavities: 1, Right pulmonary vein cut -short; 1´, cavity of left auricle; 3, 3´, thick wall of left ventricle; -4, portion of same with papillary muscle attached; 5, the other -papillary muscles; 6, 6´, the segments of the mitral valve; 7, in aorta -is placed over the semilunar valves; 8, pulmonary artery; 10, aorta and -its branches. (Allen Thomson.)] - -The heart itself is a hollow conical organ composed of cardiac muscle, -a combination of smooth and striated fibers found nowhere else in the -body. It lies obliquely, base up, between the lungs, suspended by the -great blood-vessels and with the apex directed downward, forward, and -to the left, the apex beat being normally felt in the fifth intercostal -space, one inch inside and two inches below the left nipple. In size -it varies in different people and is generally smaller in women than -in men. On the average it is five inches long, three and a half inches -broad, and two inches thick. A man’s heart usually weighs about eleven -ounces and that of a woman nine ounces. It never leaks except from -disease and such leakage is fatal. - -_The Cavities._--The heart contains four cavities, two _auricles_ above -and two _ventricles_ below, with a longitudinal septum between the -auricle and ventricle on the right and those on the left. The posterior -surface is largely made up of the left ventricle and the anterior of -the right ventricle. The right auricle, which receives the blood from -the general circulation, has a capacity of about two fluid ounces and -is larger than the left, which receives the blood returning from the -lungs, though its walls are thinner. Of the ventricles the left is the -larger and its walls are about three times as thick as those of the -right, for it has to send the blood all over the body. All the cavities -are lined with smooth, transparent, serous membrane, the _endocardium_, -which is continuous with the intima of the great vessels. - -[Illustration: FIG. 41.--Orifices of the heart, seen from above, both -the auricles and the great vessels being removed: _PA_, Pulmonary -artery and its semilunar valves; _Ao_, aorta and its valves; _RAV_, -tricuspid, and _LAV_, bicuspid valves; _mv_, segments of mitral valve; -_lv_, segment of tricuspid valve. (Huxley.)] - -_The Valves._--The opening from the auricle into the ventricle on -either side is guarded on the ventral side by a valve formed of folds -of endocardium. The valve on the right side has three flaps or cusps -and is called the _tricuspid valve_, while that on the left has two -flaps, larger and thicker than those of the tricuspid, and is known as -the _bicuspid_ or _mitral valve_. The flaps of either valve are kept -from being forced into the auricle in closing by fine tendinous cords, -the _chordæ tendineæ_, which are attached to the _columnæ carneæ_, -muscular bands or columns projecting from the walls of the ventricle, -which contract and hold the chordæ tendineæ taut. The opening into the -pulmonary artery is from the posterior part of the right ventricle -and is guarded by the _semilunar_ or _pulmonary valve_, while the -aortic opening from the left ventricle is guarded by a similar valve, -the _aortic valve_, the most important valve in the body. All these -valves are planned primarily to prevent regurgitation of the blood -during contraction of the heart muscle. Pressure in the ventricle must -exceed that in the arteries before the semilunar valves will open and -the blood can be driven out, just as the auriculo-ventricular valves -remain closed until the pressure in the auricles exceeds that in the -ventricles. - -The _heart beat_ is caused by the twisting of the heart upon its axis -during contraction of the muscle. Normally it beats rhythmically and -regularly, whatever a person does, at a rate of about seventy-two -contractions to the minute in the adult. To the regular _cardiac -cycle_, as it is called, there are two periods, the _systole_ and the -_diastole_, the former representing the period of contraction of the -ventricles, when the blood is sent to the lungs and over the body, -and the latter representing the period of rest following the emptying -of the ventricles, during which they are refilled. Contraction of -the heart occupies one-fifth of the time of one beat, dilatation -two-fifths, and the pause two-fifths. There are really two systoles, -one of the auricles and one of the ventricles, but they come so close -together that they are practically simultaneous so far as sound is -concerned, though they can be distinguished by sight. During systole -the tricuspid and mitral valves close sharply to prevent regurgitation -into the auricles, while the semilunar valves open to let the blood -out. The cardiac cycle is, therefore, as follows: - -[Illustration: FIG. 42.--Diagram of the circulation. (After Kirke.)] - -=Circulation.=--The blood, after it has given off its oxygen and -collected carbon dioxide, returns to the heart through two main -channels, the _superior_ and _inferior venæ cavæ_, the former bringing -the blood from the upper part of the body, including the head, neck, -and arms, and the latter from the lower part below the diaphragm. The -two vessels empty along with the _coronary sinus_, which is guarded -by the _coronary valve_, into the right auricle. At the same time -that they empty into this auricle the four _pulmonary veins_, the -only veins that carry arterial or oxygenated blood, are emptying the -fresh blood from the lungs into the left auricle. When both auricles -are full, they contract and send the blood into the ventricles, the -_auricular systole_. As the blood comes through into the ventricles it -probably comes around by the walls and closes the auriculo-ventricular -valves, though just how the valves close is not certain. When the two -ventricles are full they in turn contract, the _ventricular systole_, -and the blood is forced out, that in the right ventricle passing to the -lungs for its new supply of oxygen through the _pulmonary artery_, the -only artery to carry venous blood, and that from the left ventricle -entering the aorta for general distribution through the body. Following -the systole is a pause, the _diastole_, while the heart fills again. - -[Illustration: FIG. 43.--The fetal circulation.] - -_Circulation in Fetus._--In the fetus there is direct communication -between the two auricles through the _foramen ovale_, which normally -closes at birth, though occasionally it remains open. There is also -communication between the pulmonary artery and the arch of the aorta -through the _ductus arteriosus_. The freshly oxidized blood comes -to the fetus through the placenta, from which it is brought along -the umbilical cord in the umbilical vein to the liver and thence to -the inferior vena cava, where it mixes with the blood from the lower -extremities. By the inferior vena cava it is carried to the right -auricle, where the _Eustachian valve_--a valve between the inferior -vena cava and the auriculo-ventricular opening, larger in the fetus -than in later life where it serves no special purpose--guides it across -the auricle and through the foramen ovale to the left auricle. From -this auricle, together with a small amount of blood from the lungs, -it goes to the left ventricle and is distributed by the aorta almost -entirely to the head and upper extremities. Hence their large size and -perfect development at birth. Returned from the upper extremities by -the superior vena cava, the blood enters the right auricle again and, -passing over the Eustachian valve this time, descends to the right -ventricle, from which the greater part passes by the pulmonary artery -and the ductus arteriosus to the descending aorta, though a small -amount keeps on through the pulmonary artery to the lungs. In the aorta -it mixes with the blood from the left ventricle and part goes to supply -the lower extremities, though the greater part is carried back to the -placenta through the two umbilical arteries. The fact that the greater -part of the blood traverses the liver accounts for its large size at -birth, while the lower extremities, which receive for the most part -blood that has already circulated through the upper extremities, are of -small size and imperfectly developed. - -=Arteries.=--After birth the arterial blood for the general circulation -leaves the heart by the aorta, the main distributing artery of the -body. Through this and its branches it is carried throughout the body -in what, with the return of the venous blood by the venæ cavæ and other -smaller veins, is known as the _systemic circulation_. The _aorta_ -ascends from the left ventricle and arches backward to the left over -the root of the left lung to descend along the spinal column at the -left to the fourth lumbar vertebra, about opposite the umbilicus, -where, considerably diminished in size by the branches it has given -off, it divides into the two _common iliacs_. For convenience its -different parts are named, according to their position, the _ascending -aorta_, the _arch of the aorta_, and the _descending aorta_, the last -being subdivided into the _thoracic_ and the _abdominal aorta_. - -[Illustration: FIG. 44.--The aortæ and their branches. (Leidy.)] - -From the ascending aorta come off the _coronary arteries_ which supply -the heart muscle itself, as the coronary sinuses carry off the venous -blood from the heart. From the arch are given off the _left common -carotid_ and _left subclavian_ and the _innominate_, which divides into -the _right common carotid_ and _right subclavian_. - -The _common carotids_ pass up the neck behind the sterno-cleido-mastoid -muscles in a line from the sterno-clavicular joint to a point midway -between the mastoid process and the angle of the lower jaw and divide -opposite the upper border of the thyroid cartilage into the _internal_ -and _external carotids_, of which the former with its branches supplies -the anterior part of the brain, the eye and forehead, and the latter -the neck and face. - -The _subclavian_ is the artery of the upper extremity but its vertebral -branch goes to the brain, where with its fellow it forms the _basilar -artery_, whose branches together with the branches of the internal -carotid form the _circle of Willis_ at the base of the brain. Other -branches of the subclavian are the _thyroid axis_, with branches to -the neck and shoulders; the _internal mammary_, with branches to the -chest walls, mediastinum, and diaphragm, such as the musculo-phrenic -and superior epigastric; and the _superior intercostal_. At the lower -border of the first rib, over which it passes, the name _axillary_ is -substituted for _subclavian_, while at the lower border of the axilla, -where it starts down the arm, it is called the _brachial artery_. At -the elbow the brachial divides into the _radial_ and _ulnar arteries_. -The _axillary artery_ sends branches to the chest and shoulder and is -more frequently injured than any other artery except the popliteal. -_Aneurism_ may occur in it and is very likely to occur in the thoracic -aorta. - -From the _thoracic aorta_ branches go to various of the chest contents, -while the _abdominal aorta_ supplies the abdominal viscera. Among the -branches of the abdominal aorta are: the _celiac axis_, which has a -gastric, an hepatic, and a splenic branch; the _superior_ and _inferior -mesenteric_ to the intestines; the _renal_; the _suprarenal_; the -_spermatic_ or _ovarian_; the _inferior phrenic_; and the _lumbar_. - -The _common iliacs_ divide at the upper edge of the sacrum into the -_external_ and _internal iliacs_, of which the latter with its branches -supplies the walls and viscera of the pelvis and the inner part of the -thigh. The external iliac and its branches go to the thigh, leg, and -foot. - -=Veins.=--Of the veins few need be mentioned by name. The deep veins -have the same names as the arteries they accompany, though there are -two _innominate veins_ where there is only one innominate artery, -the _subclavian_ and _internal jugular_ veins on either side joining -to form an innominate vein and the two innominates in turn forming -the _superior vena cava_. Of the superficial veins the _external_ -and _internal jugular_ correspond to the common carotid arteries and -return the blood from the head and face. The external jugular vein is -important because it is the largest superficial vein in the neck and -is often cut in suicide. The _median vein_ is found at the bend of -the elbow and is used in letting blood and in giving salt solution, -while the _basilic_ is on the inner side and the _median cephalic_ -on the outer side of the upper arm. _Varicosity_ often occurs in the -_internal_ or _long saphenous_ and the _external_ or _short saphenous_ -in the leg. The _inferior vena cava_ is formed by the juncture of the -two _common iliac veins_. - -=Portal Circulation.=--The portal system of veins includes four large -trunks which collect the blood from the viscera of digestion, the -_superior_ and _inferior mesenteric veins_ from the intestines, the -_splenic vein_ from the spleen, and the _gastric_ from the stomach. -These join together to form the _portal vein_, the only vein that -breaks up into capillaries. This divides and ramifies through the -liver, whence it emerges as the _hepatic veins_. The whole is known as -the portal circulation. - -=Pulmonary Circulation.=--Of the pulmonary circulation and its vessels -a few words might also be said. The _pulmonary artery_, which carries -the blood from the right ventricle to the lungs, is only about two -inches long and divides into a right and a left pulmonary artery, which -pierce the pericardium and go to their respective lungs. The right one -is the larger and longer, for it has farther to go and gives off a -branch to supply the third lobe of the right lung. The vessels finally -divide and subdivide, terminating in the _pulmonary capillaries_. -The venous capillaries then gather together to form a main vein in -each lobule, these veins uniting into two trunks for each lung, the -_pulmonary veins_, which empty into the left auricle. - -=Nerves of Heart.=--The muscular fibers of the heart have the power -of rhythmical contraction. Independent nerve centers or ganglia are -also found in the muscular walls and influence the mechanism of the -heart, especially the acceleratory mechanism. Thus, in some of the -lower animals the heart can be removed from the body, and if placed in -normal salt solution will go on beating for some time. The heart is -controlled, however, by two nerves, the _vagus_ or _pneumogastric_ and -the _sympathetic_. Of these the vagus is the inhibitory mechanism. It -acts as a check and makes the heart’s action regular and rhythmic. If -it is cut, the action of the heart becomes very rapid and irregular. -The sympathetic is the acceleratory mechanism. When the vagus alone -is stimulated, it first slows, then stops the heart, for it weakens -the systole and prolongs diastole. Acceleration follows stimulation -of the sympathetic, both the rapidity and the force of the beat -being increased. When a person faints from a blow in the abdomen, it -is because the pneumogastric is affected and inhibits the action of -the heart. The work of the heart is very dependent upon its nervous -condition and functional diseases of the heart are practically wholly -due to nervous derangement. - -=Heart Sounds.=--Through the stethoscope two heart sounds may be heard. -They are known as the first and second sounds. The first is a soft, -rushing sound, stronger and louder than the other, and is caused in -part by the contraction of the muscle itself when the blood is forced -out and in part by the closure of the auriculo-ventricular valves. -The second sound is shorter and sharper, a snap, and is caused by the -closure of the semilunar valves when the contraction of the ventricles -ceases and they begin to refill. In certain diseased conditions, where -the edges of the valves are roughened, they do not snap properly and -the sound varies from the normal. - -=The Heart Beat.=--The rate of the heart beat is proportionate to the -size of the person and increases in rapidity as the size diminishes. -If the ear is placed over the abdomen of a pregnant woman, the heart -of the fetus can be heard beating very rapidly. In prolonged labor it -may become more rapid or very faint and warn the doctor that something -should be done. The usual rate of the pulse in the fetus is 140 to 150 -times a minute, though it varies with size and sex. At birth it drops -to 140 to 130; for the first year it is 130 to 115; for the second -year 115 to 105; for the third year 105 to 95; from the seventh to the -fourteenth years 80 to 90; from the fourteenth to the twenty-first -years 75 to 80; from twenty-one to sixty 60 to 75. In old age it rises -a little and is 75 to 80. The rate is higher in the average woman -than in the average man and increases with exercise, with increase of -temperature, and in high altitudes, where the atmospheric pressure is -less. - -At each beat of the heart from four to six ounces of blood are -expelled into the pulmonary artery and the aorta, and in 22 or 23 -beats all the blood in the body passes through the heart. The power -exerted by the heart every minute in thus driving the blood upon its -course has been estimated as sufficient to raise its own weight, -three-quarters of a pound, the height of the Washington monument or 150 -meters; for the ventricles have to force the blood into vessels already -full. - -=Factors Affecting Circulation.=--There are three main factors in the -circulation: 1. the systole, which gives the blood its first impulse; -2. the peripheral resistance in the capillaries, which serves to hold -it in check, slowing the circulation and doing away with its rhythmic -character, and 3. the elasticity of the walls of the arteries. - -If a ligature is tied about an artery, there is a swelling on the side -toward the heart, while in the case of a vein, the swelling is on the -side away from the heart, that is, the swelling is in either case on -the side from which the blood comes. When an artery is cut, however, -the blood comes out rhythmically in spurts, though from a cut vein it -oozes slowly and regularly. For the blood is pumped out by the heart -rhythmically and its rhythmic beating against the walls of the artery -is felt in the _pulse_, which follows slightly after the beat of the -heart itself. The pulse is due to the fact that the vessels into which -the blood is forced are already full. This causes a local dilation at -the beginning of the artery which passes with diminishing force along -its entire length, the distention being due to the fact that more force -is needed to drive the blood through the small arteries and capillaries -than to stretch the elastic walls of the aorta and the large arteries. -It is this elastic character of the arteries that makes the blood flow -constant, for otherwise the blood would come intermittently in jets, as -it is pumped from the heart. The elastic walls of the vessels, however, -offer a certain resistance to the pumping of the fluid through them and -at the same time, by relaxing between whiles, allow a certain amount of -fluid to be retained in them, so that they continue full and the flow -is more or less constant. The insufficient outlet also helps to make -the flow constant. - -By the time the blood reaches the veins its rhythmic character has -been done away with, but though there are no elastic walls in the -veins, it still has force enough after the slowing in the capillaries -to return to the heart. In this it is aided to a certain extent by -the valves and by the action of the skeletal muscles as they contract -and expand, especially in the arms and legs, where the blood runs -perpendicularly and there is a high column to be supported. There are -also more veins than arteries, each large artery having two large -veins, the venæ comites, to help get the blood back to the heart, and -the veins anastomose freely. Thus, if the blood cannot get back by one -channel it does by another. In parts like the brain, where it is very -important that there should be no compression, since any disturbance -of circulation would lead to serious results, the vessels are enclosed -in thick walls, and in the liver, through which all the blood passes -and where compression is sure to cause trouble, the veins are simply -caverns carved out in the organ and have no walls. They lie open when -the organ is opened. _Varicose veins_ are the result of valves giving -way through inherited weakness or disease so that others have an unduly -large weight to support. - -=The Pulse.=--The _pulse wave_ is characterized by a quick rise and -a slow fall, though this cannot ordinarily be distinguished by the -finger. In some slow fevers, however, the fall is very long and -distinct ripples can be felt. This is known as the _dicrotic pulse_. -With age the arterial walls grow stiffer and more rigid and less -adapted to their work. In certain cases of heart disease the heart does -not transmit all the beats to the pulse and to get the true rate the -heart must be listened to. - -The rate at which the pulse wave travels varies with the size of the -artery and the force of the heart beat but is about 15 to 20 feet -a second. The flow is most rapid in the arteries because they are -nearest the heart, where the pressure is greatest, and slowest in the -capillaries, where the area is greatest, the sectional area of the -capillaries, known as the _peripheral area_ because it is farthest from -the heart, being larger than that of the large arteries. Thus rapidity -of flow varies with pressure and with area. - -=Blood Pressure.=--Liquids, moreover, are incompressible and exert -pressure on the walls of the tubes through which they pass. The amount -of pressure depends upon the inflow and outflow, increasing directly -with the inflow and inversely with the outflow, that is, the smaller -the outlet the greater the pressure, and _vice versa_. The pressure -is also greatest nearest to the inflow and gradually decreases with -distance until at the point of outflow there is practically no -pressure. So, in the arteries the blood pressure is greatest in the -large vessels nearer the heart and gradually decreases as they branch -into smaller and smaller vessels. In passing through the capillaries, -owing to their small size and resultant increased friction, the -blood meets with more resistance, the peripheral resistance, and -this resistance usually regulates the pressure in the arteries. The -greater the peripheral resistance, as a rule, the greater the arterial -pressure. The pressure in the capillaries is very slight and in the -veins there is practically no pressure. In fact, in the large veins -near the heart the pressure is negative and the blood is almost sucked -into the heart. - -Pressure, then, is greatest in the arteries and least in the veins, -while the rate of flow is fastest in the arteries--300 to 500 -millimeters a second--and slowest in the capillaries--75 millimeters -a second--being a little faster again in the veins--200 millimeters a -second. - -Blood pressure is gauged by opening a vessel and inserting a -_manometer_, the pressure being determined by the height to which the -mercury is raised. In man the pressure in the arteries is 120 to 160 -millimeters. It is considerably heightened during inspiration by the -increased pressure of the lungs on the heart and great vessels. In -pericarditis the opposite is true. - -When the blood pressure is high, the _pulse_ is small and travels fast, -because the wall of the artery is already highly stretched. Such a -pulse is hard and incompressible. A large pulse occurs where the heart -is strong and the pressure is low, owing to peripheral dilatation. A -low-pressure pulse is soft and compressible if the heart beat is weak. -A slow pulse is generally stronger than a rapid one. - -The _nerve supply of the blood-vessels_ comes from the spinal cord -through the vasomotor nerves, which are connected with the sympathetic -system and are distributed to the smooth muscle fibers of the vessels. -They are of two classes, the _vasoconstrictors_, which diminish the -lumen of the vessels, and the _vasodilators_, which increase the size -of the vessels. By these nerves the general tone of the arteries is -kept up. They are distributed chiefly to vessels in the skin and -in the abdominal organs and the constrictors are probably the more -important. When the constrictors are stimulated, three phenomena occur: -1. diminished flow through the vessel, due to its diminished size; 2. -increased general arterial pressure, and 3. increased flow through -the other arteries. When the dilators are stimulated the opposite -effect is produced: 1. the flow through the vessel is increased; 2. -there is decreased arterial pressure, and 3. there is decreased flow -through the other arteries. The palor of fright is due to the action -of the vasoconstrictor nerves of the face and blushing to the action -of the vasodilators. Heat stimulates the vasodilators so that more -blood goes to the skin, perspiration begins, and the body is cooled by -evaporation. Cold stimulates the vasoconstrictors and the blood is kept -within the body, where it cannot cool. If a part has too much blood, -an impulse passes by the vasoconstrictors to lessen the supply, while -if more blood is needed a message goes to the central nervous system -and an impulse passes by the vasodilators to flush the organ. The more -active a part is in functioning the greater the number of capillaries, -except in the brain, which has only large vessels. The vessels of the -intestines contain much blood and are capable of containing all the -blood in the body. - -=The Blood.=--The blood itself, which thus circulates through the body, -carrying nutrition to the tissues and removing waste, is a complex -fluid of a bright red color. Its amount has been calculated to be -about one-thirteenth of the body weight. One-fourth of it is generally -in the heart, lungs, and large arteries and veins, one-fourth in the -liver, one-fourth in the skeletal muscles, and one-fourth variously -distributed through the other organs. If there is too little blood, the -vital processes cannot go on as they should, while too great a supply -causes weakness rather than strength. So the tendency is to keep the -amount constant and any blood added is disposed of and any blood lost -is replaced. In starvation it is the last tissue to be used up, for on -it the life of the other tissues depends. - -_Composition._--In composition the blood is practically the same in -all arteries and fundamentally the same everywhere, but in passing -through certain organs certain substances are added to or taken from -it, so that its character changes more or less. Thus it varies somewhat -in composition in different parts of the body, as in the liver and -kidneys. It has five main functions: 1. the conveying of fuel from the -digestive tract to the tissues, or force production; 2. the carrying of -oxygen to the tissues; 3. the carrying of tissue-building materials, -or tissue building; 4. the distribution of heat; and 5. the removal of -waste products. - -The blood is slightly alkaline in reaction, of a saltish taste, and has -a specific gravity of 1055. Its temperature is about 100° Fahrenheit or -37.8° Centigrade. It is made up of two parts, the _plasma_ or fluid -portion and the _corpuscles_ or solid portion. The plasma, again, which -is transparent and almost colorless, consists of two materials, the -_blood serum_ and _fibrin_. Fibrin does not exist as such in the body -nor in freshly shed blood, but there is a substance named _fibrinogen_ -which is worked on by another substance, the _fibrin ferment_, to form -fibrin. Both fibrin ferment and fibrinogen can be isolated from the -blood. - -_Coagulability._--In the body the blood is perfectly fluid and under -normal conditions does not coagulate. But, though fluid when first -shed, upon standing it gradually becomes viscid, that is, in two or -three minutes, then jelly-like, in five to ten minutes, and grows -firmer and firmer until there finally appears around this jelly-like -mass or clot a yellowish fluid, the _serum_. The _clot_ is made up of -the corpuscles and fibrin. If some blood is drawn and set on ice until -the corpuscles settle, the plasma can then be drawn off, and after it -has stood a while in a warm place coagulation will take place, a mass -of fibrin forming in the middle. It takes from one to two hours for -clotting to be complete. In very slow clotting at a low temperature the -white corpuscles appear in a layer on top of the clot, the buffy coat. - -Of _fibrin_ little is known, but its formation is the most important -step in clotting, as its presence is absolutely essential. If it -is removed by whipping, the blood will not clot. It is a delicate, -stringy material, elastic and contractile, and contains certain salts -of lime and magnesium, upon whose presence its power of coagulation -depends. The coagulability of blood differs in different people and is -occasionally so little as to make operation dangerous. - -The most favorable temperature for clotting is that of the body, -extreme heat preventing it and cold delaying it. That the blood does -not clot in the body must be due to some relation between the blood -and the walls of the arteries and veins that prevents it, just as the -walls of the stomach are not digested by the juices secreted. Though -coagulation does not normally take place in the body, it does take -place when a blood-vessel is injured or when the blood comes in contact -with the air, a wise provision of nature, as otherwise the tendency -would be for bleeding to go on indefinitely after injury. The greater -the surface with which the blood comes in contact the more quickly it -clots. Injury to the vessel wall itself is necessary; the endothelium -must be cracked. Under extreme injury the muscular coat of the vessel -undergoes spasmodic contraction and partially closes it. Hence a wound -caused by tearing is less likely to bleed than one due to cutting. - -The valves of the heart, which are covered with endothelium, are -frequently the seat of fibrin coagulation, bits of the fibrin thus -formed giving rise to conditions in various kinds of heart trouble. Or -the bits of fibrin float in the blood and perhaps lodge in the small -vessels of the brain and cause apoplexy. Pus in various parts of the -body will set up coagulation in nearby arteries. In fact, the presence -of any foreign substance in the blood causes clotting. - -[Illustration: FIG. 45.--Cells of blood: _a_, Colored blood-corpuscles -seen on the flat; _b_, on edge; _c_, in rouleau; _d_, blood platelets. -(Leroy.)] - -=Blood-corpuscles.=--The solid parts of the blood are the red -corpuscles, the white corpuscles, and the blood plaques or plates. -It is to the _red corpuscles_, or _erythrocytes_ which number about -5,000,000 to the cubic millimeter of blood, that the color of the -blood is due. Under the microscope they appear as small, spherical, -biconcave discs with a slightly greenish-yellow color, which have -a tendency to form in rouleaux. They are homogeneous, with no -limiting membrane, and are made up of a fine network of tissue, the -_stroma_, in which is embedded the hemoglobin or coloring matter. -This hemoglobin is a crystalline body and the most complex substance -known to chemists. The corpuscles are very flexible and can squeeze -through small apertures, as in the tiny capillaries, and regain their -shape. They are probably formed chiefly in the red bone marrow at the -ends of the bones, which under the microscope shows red corpuscles in -various stages of growth, and also in the spleen, for which no other -use is known. Their function is to carry oxygen, which forms a chemical -combination, though an extremely loose one, with the hemoglobin. As the -tissues are more greedy of oxygen than is the hemoglobin, they rob the -corpuscles of it. - -[Illustration: FIG. 46.--Various forms of leucocytes: _a_, Small -lymphocyte; _b_, large lymphocyte; _c_, polymorphonuclear neutrophile; -_d_, eosinophile. (Leroy.)] - -The _white corpuscles_ or _leucocytes_ are much fewer in number, -about one to from 300 to 700 of the red, the average number being -5,000 to 10,000 to the cubic millimeter. They are larger than the red -corpuscles, colorless, and spherical when at rest. Their structure is -more definite, there being a definite cell substance or protoplasm -and one or more nuclei, which vary more or less in shape and size. -The corpuscles are classed in accordance with these variations in the -nuclei. They are most numerous during digestion and are probably formed -in the lymphatic system, constantly passing from the lymphatics to the -arteries and veins. For they have the function of amœboid movement by -which they not only wander from place to place in the blood, keeping -close to the sides of the vessels, but pass through the walls of the -capillaries, probably between the cells which form their lining, into -the lymph spaces. This is known as _migration of the white corpuscles_. -In inflammation they collect in the inflamed area to assist in allaying -the inflammation by absorbing and carrying off its products. For they -carry waste products and destroy poisons, acting as scavengers and -protectors of the body. When they are unsuccessful and the inflammation -gets the better of them, they become _pus corpuscles_. - -Besides the corpuscles there are seen floating in the blood small -disk-like substances with no special characteristics, the _blood -plaques_ or _plates_, whose function is unknown. - -In _anemia_ the red corpuscles are diminished and the white corpuscles -and blood plaques increased in number. After excessive bleeding normal -salt solution is injected, subcutaneously or by rectum, as being nearly -equivalent to blood serum in composition, and the renewal of the -solid elements is left to time. The length of time needed for their -restoration is about a week, except in the case of the hemoglobin, -which takes longer. - - - - -CHAPTER IX. - -THE LUNGS AND RESPIRATION. - - -Besides the heart and the great vessels the chest contains the lungs, -the chief organ of respiration, which, with the rest of the respiratory -system, will now be treated. The nose and mouth, through which the air -first enters the body, have already been spoken of. From them the air -passes through the larynx to the trachea, thence to the bronchi, and so -to the lungs, where the supply of oxygen for the tissues is taken from -the air by the hemoglobin of the blood. - -=The Larynx.=--The larynx lies in front of the pharynx at the upper -and fore part of the neck, where it causes a considerable projection, -known as _Adam’s apple_. It is a triangular box, base up, flattened -at the back, in front, and at the sides, but becoming cylindrical -below. Above it opens into the bottom of the pharynx and below into the -trachea. It is lined with mucous membrane. Its opening at the base of -the tongue is closed during swallowing by a little door-like valve of -fibro-cartilage, the _epiglottis_, to prevent the entrance of food. - -Nine _cartilages_ go to make up the larynx, of which the most important -are the thyroid and cricoid cartilages and the epiglottis already -mentioned. The _thyroid_ is the largest and is open behind, its two -alæ or wings meeting in an acute angle in front and forming the Adam’s -apple, always more prominent in the male than in the female. It is -attached above to the hyoid bone and has cornua or horns on either -side, top and bottom. The _cricoid_ or ring-like cartilage resembles -a seal ring with the stone placed posteriorly. It is stronger than -the thyroid and forms the lower part of the cavity of the larynx. -Inside and resting on the upper border of the cricoid are the two -smaller _arytenoid_ or pitcher-like cartilages, pyramidal in shape, -and surmounting these again the two _cornicula laryngis_. The two -_cuneiform cartilages_ are in the free borders of the folds of mucous -membrane which extend from the apex of the arytenoids to the sides of -the epiglottis. Numerous small muscles serve to bind these various -cartilages together. - -At the angle of the thyroid cartilage in front are attached the -epiglottis at the top and just below that the _superior_ or _false -vocal cords_, two folds of mucous membrane enclosing the _superior -thyro-arytenoid ligaments_. Lower still are found the _inferior_ or -_true vocal cords_, which are formed by the _inferior thyro-arytenoid -ligaments_ covered with a thin, tightly fitting mucous membrane. Both -sets of vocal cords as well as the epiglottis may be seen by means -of a head and a throat mirror. Between the true vocal cords is a -narrow triangular interval called the _glottis_. It is by means of the -vibrations of these cords that sound is produced. The false vocal cords -cannot produce sound, though they can modify it indirectly. Quality of -voice, as treble, base, etc., depends upon the size of the larynx and -the length and elasticity of the vocal cords. Modulation is produced by -changing the form of the cavity of the mouth and nose. In whispering -the lips take the place of the vocal cords and produce sound by the -vibration of their muscular walls. - -Instead of tracheotomy _laryngotomy_ is sometimes done in the -depression between the thyroid and the cricoid, which may be felt on -the living. _Foreign bodies_ sometimes get into the larynx and have -to be removed, or the mucous membrane may become inflamed, causing -_laryngitis_. _Syphilis_ attacks the larynx, and _tuberculosis_ and -_cancer_ of the larynx occur, these last two being generally fatal. -_Edema of the glottis_ may also occur. - -[Illustration: FIG. 47.--The larynx, trachea and bronchi (After -Sobotta.)] - -=The Trachea.=--The trachea is a membranous tube extending down from -the larynx for about four and a half inches to the fourth or fifth -dorsal vertebra, where it divides into the right and left bronchi. It -is formed of sixteen to twenty imperfect cartilaginous rings, open -behind, enclosed in a double elastic fibrous membrane, and is lined -with ciliated mucous membrane. The rings are for strength and in -the interval at the back where they are wanting there is one layer -of longitudinal and another of transverse unstriped muscle fibers. -The passage is kept clear by the action of the cilia, which sweep up -and out any particles of dust that become entangled in the mucus. -_Tracheotomy_ is generally done about one inch below the cricoid, just -above the sternal notch, incision being made through the cartilage. - -[Illustration: FIG. 48.--The upper thorax of a child eight years old, -showing the thyroid and thymus glands. (Sobotta.)] - -Extending up on either side of the upper trachea in the neck are the -two lobes of the _thyroid gland_, the isthmus, which connects the -lobes, covering the trachea below anteriorly. The function of the gland -is obscure, but it has an internal secretion of great importance in -the metabolic processes. Its removal or disease is followed by general -disturbances of mind and body. The injection of thyroid extract has -proved effective as treatment. In _goiter_ the gland becomes enlarged. -The _thymus gland_ lies below the thyroid gland at birth, in front of -and at the sides of the trachea, and runs down behind the sternum. It -is largest at the end of the second year, after which it atrophies, -being almost absent at puberty. It, too, is ductless and its function -is not well understood. - -=The Bronchi.=--The two bronchi, of which the right is the larger and -shorter, resemble the trachea in structure. As they enter the root -of the lung they divide, the right into three and the left into two -branches, one for each lobe, after which they divide and subdivide, -the bronchioles becoming smaller and smaller and finally ending in the -_infundibula_, pouch-like places lined with air cells, in which cilia -keep the air in motion. As they grow smaller the bronchioles gradually -become wholly membranous. - -[Illustration: FIG. 49.--Relation of lungs to other thoracic organs. -(Ingals.)] - -=The Lungs.=--The lungs themselves, two in number, lie each in a serous -sac or _pleura_, similar in structure to the pericardium and serving -a like purpose. The outer layer of the pleura is reflected back over -the thoracic wall and diaphragm. There is no pleural cavity in health -between the two layers of the pleura, the two surfaces being in close -contact, though moistened with lymph to prevent friction during -respiration. In inflammation of the pleuræ or pleurisy, they become -thickened and roughened and friction results, as is shown by the sounds -heard through the stethoscope. Friction causes effusion and fluid -collects. This generally absorbs again, but occasionally the serous -fluid becomes pustular and _empyema_ results. - -In front, between the two pleuræ, which are wholly separate, is the -_mediastinal space_ or _mediastinum_, which extends from the sternum -to the spinal column and contains all the thoracic viscera except the -lungs and heart, that is, the trachea, esophagus, thoracic duct, and -many large vessels and nerves. - -[Illustration: FIG. 50.--Diagrammatic representation of the termination -of a bronchial tube in a group of infundibula: _B_, Bronchial tube; -_LB_, bronchiole; _A_, atrium; _I_, infundibulum; _C_, alveoli. (de -Nancrede.)] - -Roughly speaking, the lungs begin at the sterno-clavicular articulation -above, the apex coming up above the level of the first rib, and extend -downward together to the fourth cartilage, where the lower margins -gradually separate, the lowest lung limit being the eleventh rib in -the vertebral region. Each lung is conical. The apices extend upward -and the bases, which are broad and concave, rest upon the diaphragm. -The right lung is divided by a fissure into three lobes, the left into -two. The root consists of a bronchus and pulmonary arteries, veins, -lymphatics, and nerves. The tissue itself is composed of an aggregation -of lobules, each consisting of a terminal bronchiole with its alveoli -or air cells, blood-vessels, and nerves, a lung in miniature. The blind -pouches which the air cells surround are called _infundibula_ and are -separated by delicate membranous septa in which lie the capillaries of -the pulmonary artery, thus exposing the blood to the air on two sides. -The lung itself is supplied by the bronchial arteries from the thoracic -aorta and by branches of the sympathetic and pneumogastric nerves. - -At birth the lungs are pinkish-white in color but in later life they -are marked with slate-colored patches, due to the deposit in the lung -tissue of particles of dirt breathed in. They are light, spongy, and -highly elastic, and will float in water, crepitating upon pressure -owing to the air in the tissue. - -At birth, also, the lungs are solid, so that the first air has to -overcome adhesions between the collapsed walls of the bronchioles and -air sacs, but after they are thus gradually unfolded, in that they are -of extensible material and open to the air above, atmospheric pressure -from within keeps them distended to the full extent of the chest, which -is air tight. They never collapse afterwards unless puncture of the -chest wall, as in stabbing, causes collapse, in which case the lung -shrivels into a small ball. - -=Respiration.=--That the organic materials used by the body as food may -give up their energy they must be broken up, and for this oxygen is -needed. The supply of oxygen for the purpose is brought to the tissues -by the blood, which acquires it in the lungs, and the waste product -of combustion, carbon dioxide, is carried off in the same manner. The -lungs are, therefore, adapted to take in large quantities of air and -to keep up a rapid exchange of oxygen and carbon dioxide in the blood. -This process of supplying oxygen to the tissues and of removing carbon -dioxide and other waste is ordinarily an involuntary act, though it can -be regulated temporarily, and is known as respiration or breathing. - -There are two periods to respiration: 1. _inspiration_ or the drawing -in of air, and 2. _expiration_ or the expulsion of air from the lungs, -the former process being a little shorter than the latter. A pause -follows each expiration before there is another inspiration. At birth -the normal rate of respiration is 42, but it grows slower as the child -grows older, being 26 at the age of five or six, while in the adult it -averages 17 to 20 times a minute. It is slower during sleep and more -rapid during physical activity. The average amount of air taken in with -every inspiration is 30 cubic inches and the minimum air space per -individual should be 3000 cubic feet per hour. - -Breathing is of two kinds, _diaphragmatic_ or _abdominal_ and _chest_ -or _rib_ breathing, the former usually being more pronounced in men -than in women, probably because of centuries of tight dressing on the -part of the latter. As a rule, however, both diaphragm and ribs come -into play; for in inspiration, which is an active movement, the thorax -becomes enlarged from before backward, laterally, and vertically. -The ribs are raised by the external intercostals chiefly, though the -internal intercostals aid somewhat, and swinging out upon the vertebræ, -widen the chest as well as deepen it. The diaphragm, which is dome-like -when relaxed, becomes flattened in contraction and so increases the -size of the chest from above downward. As the chest enlarges, the lungs -expand, the air in them becomes rarefied, and more air rushes in. -When the lungs are full they relax and the muscles relax after their -contraction, so that expiration is a passive movement, due largely to -the elastic relaxation of lungs and muscles, the air being driven out -by the lessened capacity of the lungs. - -_Difficult Breathing._--In heart and lung troubles, where too little -oxygen is carried to the tissues, dyspnœa or difficult breathing -results and may even advance to _asphyxia_, a condition in which no air -is obtained. In difficult or labored respiration the pectoral muscles -are used in inspiration and the scaleni, which pass from the vertebræ -of the neck to the sternum, develop and become powerful. The levatores -of the ribs may also assist, and even the muscles of the neck and arms -may help out, while in forced expiration the abdominal muscles are -called into play. The glottis opens and closes rhythmically as the air -enters and leaves the lungs, and the nostrils add their mite in the -struggle for oxygen. Finally there may be scarcely a muscle in the body -that is not striving to aid the respiration, and general convulsions -may result, followed by exhaustion and death. - -_Air._--In ordinary breathing the lungs are not used to their full -capacity and the air ordinarily used is known as _tidal air_. In forced -inspiration the lungs are filled to their fullest extent and the air -then taken in in excess of the tidal air is known as _complemental -air_. In like manner, the difference between the air ordinarily -breathed out and that breathed out in forced expiration is known as -_supplemental air_. The sum of these three is the _vital capacity_ of -the lungs, while beyond this there is probably some air that is never -expelled, the stationary or _residual air_. - -_Respiratory Sounds._--The entrance and exit of the air is accompanied -by respiratory sounds or murmurs, which vary according to their -position in the trachea, the bronchi, or the bronchioles and are -modified in diseases of the lungs and bronchi, when they are often -called _râles_. - -_Changes in Air in Lungs._--In passing through the nose and the rest -of the respiratory tract the air is warmed to body temperature and -saturated with moisture. After its entrance into the lungs various -changes take place in it through the mingling of the tidal with the -residual air. Thus, it gives up about 4 or 5 per cent. of its oxygen -and acquires some 4 per cent. additional carbon dioxide, while the -amount of nitrogen remains about the same. By its giving up more oxygen -than it receives carbon dioxide, its volume is slightly diminished. -Exhaled air also contains traces of ammonia and certain organic -matters, generally the results of decomposition, which give a bad odor -to the breath and are more dangerous in a close room than the mere -lack of oxygen or the presence of carbon dioxide. Indeed, the amount -of oxygen may be very much diminished, being reduced even to 5 or 6 -per cent. instead of the normal 21 per cent., without being noticed -or giving rise to any immediate bad results. Yet the importance of -ventilation is very evident. - -_Effect on Blood._--Respiration causes changes also in the blood, -the venous blood being purple and the arterial bright red. This -difference in color is due to the absence or presence of oxygen, which -is not absorbed or dissolved by the blood but forms a rather unstable -compound, _oxyhemoglobin_, with the hemoglobin of the blood. As the -oxygen is removed in the passage of the blood through the body, there -results in venous blood reduced hemoglobin, which is of a purplish -color. Upon exposure to the air, however, it absorbs oxygen once more -and resumes its scarlet color. If carbon monoxide gets into the blood, -as in cases of gas poisoning, it drives off the oxygen and forms a more -stable compound with the hemoglobin, whence the difficulty in restoring -a person so poisoned. - -_Nervous Mechanism._--Nervously, respiration is controlled in three -ways: 1. by the phrenic nerve to the diaphragm; 2. by some fibers -of the vagus or pneumogastric, and 3. by the respiratory center in -the bulbous portion of the spinal cord. Injury to the respiratory -center means the ceasing of respiration and death. Stimulation of the -respiratory center seems to depend upon the character of the blood. If -it is well oxygenized, the breathing is slow and quiet; if there is a -lack of oxygen, dyspnœa results. Probably certain chemical substances -in the blood, which are ordinarily rapidly burned up by the oxygen but -which accumulate in its absence, serve to stimulate the respiratory -center, thus adjusting the effort to get oxygen to the need of it. -Respiration may be stopped by stimulating the mucous membrane of the -nose, as with strong ammonia. - -_Variations._--Certain variations from the ordinary respiration might -be mentioned here. A deep inspiration followed by a long expiration is -known as a _sigh_ and a very deep inspiration through the mouth only -as a _yawn_. _Hiccough_ results from a sudden inspiratory contraction -of the diaphragm during which the glottis is suddenly closed. In -_sobbing_ the inspirations are short and rapid with a prompt closing of -the glottis between. Both _coughing_ and _sneezing_ consist of a deep -inspiration followed by complete closure of the glottis and then its -sudden opening and the forcible expulsion of air. Coughing, however, -is generally caused by an irritation or obstruction of the larynx or -trachea and the air is expelled through the mouth, while sneezing is -caused by irritation of the nasal passages and the air is driven out -through the nose. _Laughing_ and _crying_ also resemble one another in -that each is an inspiration followed by a series of short, spasmodic -expirations, during which the glottis is open and the vocal cords in -characteristic vibration. They differ, however, in rhythm and in the -facial expression that accompanies them. - - - - -CHAPTER X. - -THE ABDOMEN AND THE ORGANS OF DIGESTION AND EXCRETION. - - -=The Abdominal Cavity.=--Below the diaphragm and separated from the -lowest cavity of the trunk, the pelvis, only by an invisible plane -drawn through the brim of the true pelvis, is the abdominal cavity, -which may be said in a general way to contain the organs of digestion -and the kidneys. It is protected behind by the vertebræ and anteriorly -by the lower ribs above and below by muscular walls, which make -possible the complete bending of the body. These muscles are for the -most part large and very strong and the greater number are inserted, -in part at least, into a median tendinous line, the _linea alba_, -which passes from the ensiform cartilage of the sternum above to the -symphysis pubis below. - -=Muscles.=--The _external oblique muscles_ form the outermost layer of -the abdominal wall. They rise from the external surface of the eight -lower ribs on either side and are inserted in the anterior half of the -iliac crest as well as by aponeurosis in the linea alba, where each -joins its fellow from the opposite side, the fibers running downward -and inward like the fingers in the trouser’s pocket. Along the lower -border of the aponeurosis is a broad fold, _Poupart’s ligament_. -The _internal oblique_ rises on either side from the outer half of -Poupart’s ligament and the anterior part of the crest of the ilium -and is inserted into the crest of the os pubis, the cartilages of the -lower ribs, and the linea alba. Its fibers run at right angles to those -of the external oblique. These oblique muscles serve to compress the -viscera, to flex the body, and also assist in expiration. - -The deepest of the abdominal muscles is the _transversalis_, which -rises from the outer third of Poupart’s ligament and the adjoining part -of the crest of the ilium, from the six lower costal cartilages, and -by a broad aponeurosis, the _lumbar fascia_, from the lumbar vertebræ. -It is inserted into the pubic crest and by aponeurosis into the linea -alba. There is one of these muscles on either side. - -[Illustration: FIG. 51.--Muscles of the trunk from before (left side, -superficial; and right side, deep): 1, Pectoralis major; 2, deltoid; -3, portion of latissimus dorsi; 4, serratus magnus; 5, subclavius; 6, -the pectoralis, sternocostal portion; 7, serratus magnus; 12, rectus -abdominis; 13, internal oblique; 14, external oblique; 15, abdominal -aponeurosis and tendinous intersections of rectus abdominis; 16, over -symphysis pubis; 17, linea semilunaris; 18, gluteus medius; 19, tensor -vaginæ femoris; 20, rectus femoris; 21, sartorius; 22, femoral part of -iliopsoas; 23, pectineus; 24, adductor longus; 25, gracilis. (Dorland’s -Dictionary.)] - -The _rectus abdominis_ is also really two muscles and extends from the -symphysis pubis to the cartilages of the fifth, sixth, and seventh -ribs. At first it passes back of the oblique and transversalis -muscles, but about a fourth of the way up it passes in front of the -transversalis and between two layers of the internal oblique, which -thereafter forms its sheath. Its chief duty is to flex the chest on the -pelvis, though it also compresses the abdominal viscera. - -One other muscle, a small one, is found in front, the _pyramidalis_, -which rises from the pubic crest and is inserted into the linea alba -midway to the umbilicus. - -At the back the open space over the kidneys, between the lower ribs -and the os innominatum, is closed in on either side by the _quadratus -lumborum_, which extends from the three or four lower lumbar vertebræ -and the adjacent iliac crest to the last rib and the upper four -lumbar vertebræ. It flexes the trunk laterally or forward according -as one muscle or both are used, and may aid in either expiration or -inspiration. - -The _nerves_ of the abdominal muscles are chiefly the internal -intercostals. - -=The Peritoneum.=--Lining the abdominal cavity is a serous membrane, -the peritoneum, which is reflected back over the viscera within in such -a way as to cover each one wholly or in part. Folds of peritoneum, -the _omenta_, connect the stomach with the other viscera, the most -important being the _great omentum_, which has one layer descending -from the anterior and another from the posterior wall of the stomach. -The _mesenteries_ are double layers of peritoneum which hold the -intestines to the vertebræ and posterior wall. Between their folds run -the blood-vessels. - -[Illustration: FIG. 52.--Diagram showing the nine regions of the -abdominal cavity: 1, Right hypochondriac; 2, epigastric; 3, left -hypochondriac; 4, right lumbar; 5, umbilical; 6, left lumbar; 7, right -iliac; 8, hypogastric; 9, left iliac. (Ashton.)] - -=Abdominal Regions.=--For convenience of description the abdominal -cavity has been divided into nine regions by means of two transverse -parallel lines, the one through the ninth costal cartilages and the -other just over the iliac crests, and two perpendicular parallel -lines through the cartilage of the eighth rib and the middle of -Poupart’s ligament on either side. These nine regions have been named -as follows: The right and left hypochondriac regions up under the ribs -with the epigastrium between, the right and left lumbar regions next -below with the umbilical between, and the right and left inguinal with -the hypogastric between. Others divide it into quadrants by one line -drawn across and another down through the umbilicus. The contents of -the abdomen in full are the stomach, intestines, liver, gall-bladder, -spleen, pancreas, kidneys, suprarenal capsules, and the great vessels, -that is, the organs of digestion and excretion. When distended the -bladder extends up into the abdominal cavity, as does the uterus also -when enlarged. - -=Salivary Digestion.=--Although most of the digestive organs are -situated in the abdomen, the food enters the body through the mouth, -where its prehension is a voluntary act. Here digestion also begins and -from the first the process is a double one, mechanical and chemical, -mechanical digestion consisting largely of muscular movements by which -the food is ground up and carried through the digestive tract. Thorough -mastication or grinding of the food by the teeth is necessary, while -the tongue assists by moving the food about and by mixing it thoroughly -with the _saliva_, a viscid fluid composed of water and salts and -having a slightly alkaline reaction. The saliva is secreted by the -parotid, sublingual, and submaxillary glands, and serves to soften and -dissolve the food and by virtue of its unorganized ferment, _ptyalin_, -to convert starch into sugar. Upon proteins and fats it has practically -no digestive action. Moderate warmth and an alkaline medium favor its -action, while extremes of heat or cold or an acid medium hinder it. -There is little absorption in the mouth, though starch, nicotine, and -alcohol may be absorbed in small quantities. - -=The Pharynx.=--When the food is ready for deglutition or -swallowing, it is thrust back into the pharynx, a somewhat conical, -musculo-membranous sac, situated, base upward, behind the nose and -mouth and behind, but somewhat above, the larynx. The pharynx is about -four and a half inches long and ends on a level with the cricoid -cartilage in the esophagus or gullet. It is attached to the vertebræ -at the back and opens in front into the mouth. The posterior nares, -the Eustachian tubes, and the larynx also open into it, the last being -protected by the _epiglottis_, which closes during deglutition to -prevent food from entering the air passages, just as the soft palate -is drawn back to prevent regurgitation of food into the nose. There -are three coats to the pharynx: 1. a mucous coat continuous with that -of the mouth and ciliated down to the floor of the nares; 2. a fibrous -coat, and 3. a muscular coat containing among others the constrictor -muscles which serve to carry the food down to the esophagus. Its -arteries are branches of the external carotid and its nerves come from -the spinal accessory and the sympathetic. Occasionally a _foreign -body_ gets lodged in the pharynx just out of reach of the finger and -threatens strangulation. _Retropharyngeal abscess_ on the posterior -wall occurs rarely. - -[Illustration: FIG. 53.--Position of the thoracic and abdominal -organs, front view. (Morrow.)] - -=The Esophagus.=--From the pharynx the food passes to the cardiac -orifice of the stomach, opposite the tenth dorsal vertebra, through -the esophagus, a muscular tube about nine inches long, which collapses -when empty, its lumen then appearing as a transverse slit. It, too, -has three coats: 1. an inner mucous coat; 2. an areolar coat, and 3. -a muscular coat, the muscles being arranged in two sets, an outer -longitudinal layer and an inner circular layer. By a series of rhythmic -contractions, especially of the circular fibers, the food is pushed -along, though sometimes with liquid food there is no peristaltic action -of the esophagus, the pharyngeal muscles alone sending it to the -stomach. At the lower end of the esophagus an especially strong band -of circular muscle fibers form a sort of sphincter, which prevents the -regurgitation of food. The whole act of swallowing is a reflex, not a -voluntary act and is due to irritation set up by the stimulus of the -foreign body, the food. _Stricture of the esophagus_ is common and -may be of three kinds: 1. spasmodic, occurring in nervous women; 2. -fibrous, due to scar tissue, or 3. malignant, due to cancer. - -=The Stomach.=--The stomach is a pear-shaped dilatation of the -alimentary canal, lying under the liver and diaphragm in the epigastrium -and left hypochondrium and connecting the esophagus with the small -intestine. It lies largely behind the ribs, but the greater curvature -is only two fingers’ breadth above the umbilicus and can be manipulated -through the skin. The _cardiac end_, into which the esophagus enters, -is the larger and points upward to the left. The lesser and lower end, -known as the _pylorus_, is at the right and its opening into the small -intestine is guarded by the _pyloric sphincter_. The lesser curvature -is concave and on the upper surface; the greater, convex and on the -under surface. The great omentum is attached to the latter. - -In _size_ the stomach varies more or less, that of a man generally -being larger than that of a woman, but it is usually about ten inches -long and four or five inches across. It has a capacity of about five -pints and serves as a storehouse for food. - -The stomach has four _coats_: 1. a serous coat derived from the -peritoneum; 2. a muscular coat of three layers with longitudinal fibers -continuous with those of the esophagus, circular fibers, and oblique -fibers; 3. an areolar coat, and 4. a mucous coat, which, when the -stomach is empty, is thrown into longitudinal folds or _rugæ_, and -whose surface is covered with glands, the _gastric glands_, for the -secretion of the digestive fluids. - -The _arteries_ come from the celiac axis and the _nerves_ from the -pneumogastric and the solar plexus. - -_Ulcer_ and _cancer_ of the stomach are both rather common. In -the former there is apt to be _hyper_-acidity and in the latter -_hypo_-acidity, but the rule does not always hold. In cases of ulcer -there may be hemorrhage and even perforation. Such hemorrhage can be -distinguished from hemorrhage from the lungs by its slightly acid odor -and by the frothy character of hemorrhage from the lungs. There is much -irritation at the pylorus and where there is irritation there is liable -to be cancer. - -=Gastric Digestion.=--In the stomach the food is churned and thoroughly -mixed with the gastric juices, and it is also subjected to a propulsive -movement that drives it on to the intestine. When it comes to the -stomach it is semi-solid and when it has become fluid or semi-fluid, in -which state it is known as _chyme_, it is ready to pass on. Before it -can do so, however, it must overcome the strong pyloric sphincter, and -this it does by the muscles about the sphincter pushing it constantly -on until the sphincter gives way. Probably most of the propulsive -movements take place within a few inches of the pylorus. - -The _gastric juice_ is secreted by glands in the wall of the stomach -and poured out through little tubules which project from the surface. -It is a thin, almost colorless fluid with a sour taste and odor due -to the presence of free _hydrochloric acid_, an important element in -digestion. Probably when the stomach is empty and for some twenty -minutes after the appearance of food there is no hydrochloric acid -present and, the food being alkaline, salivary digestion continues. -Then, called forth by the presence of the food, the hydrochloric acid -appears and salivary digestion ceases in the acid medium. Little -digestion of starches or fats takes place, the chief action being -on proteins, which are converted into soluble peptones. For besides -hydrochloric acid the gastric juice contains two ferments: 1. _pepsin_, -which is particularly active in aiding the digestion of proteins, and -2. _rennin_, which especially affects milk. Neither hydrochloric acid -nor pepsin seems capable of digesting food alone, but each is essential -to the other. They are secreted by different types of cells, secretion -depending upon the nerve supply and upon the presence of food. Gastric -digestion is favored by minute subdivision of the food and by the -right proportion of hydrochloric acid, which should be 0.2 per cent. -Body temperature is also advantageous. Except that proteins are put in -solution and partly digested, little digestion goes on in the stomach, -and though the rugæ afford a large absorbing surface, little absorption -takes place, although more takes place than in the mouth and in time -most foods, except fats, can be absorbed. The time of digestion varies -with different foods and in different people, but probably three to -five hours are necessary. The food leaves the stomach as _chyme_, a -fluid of about the consistency of pea soup. - -_Vomiting_ is more or less the reverse of swallowing and is generally -preceded by a feeling of _nausea_, which starts up _retching_, a more -or less involuntary effort of the stomach to throw off its contents. -To relieve the retching a long breath is taken, followed by a deep -expiration that opens the cardiac end of the stomach and allows the -abdominal muscles to force the food out. After much vomiting and -prolonged retching the pyloric end of the stomach may be affected and -bile will then appear in the vomitus. _Artificial vomiting_ may be -produced by irritation of the gastric nerve center in the brain or by -irritation of the stomach itself. - -[Illustration: FIG. 54.--The intestinal canal: 1, Stomach; 2, duodenum; -3, jejunum; 4, ileum; 5, cecum; 6, vermiform appendix; 7, ascending -colon; 8, transverse colon; 9, descending colon; 10, sigmoid flexure; -11, rectum. (Leidy.)] - -=Intestinal Canal.=--From the stomach the food passes into the -intestinal canal, a convoluted tube which extends from the stomach to -the anus and in which, more particularly in the upper portion, the -greater part of the digestion and absorption of food takes place. This -tube, which is about six times the height of its possessor, consists of -two parts, the small and the large intestines, the first four-fifths, -or about 25 feet, being small intestine. It occupies the central and -lower parts of the abdominal cavity and a small portion of the pelvic -cavity, and is attached to the spine by the mesentery, which, however, -allows great freedom of motion, so that there is little fixation to the -loops of the small intestines. - -=The Small Intestine.=--The small intestine opens out of the stomach -and has three divisions: 1. the _duodenum_, which is only about ten to -twelve inches long; 2. the _jejunum_, so called because it is generally -empty after death, which is about two-fifths of the remainder and lies -chiefly in the umbilical region and the left iliac fossa, and 3. the -_ileum_ or _curved intestine_, the remaining three-fifths, which gets -its name from its numerous coils and which lies in the middle and the -right side of the abdomen. There is no direct division between the -jejunum and the ileum, but the first part of the former and the last -part of the latter are quite different in character. At its entrance -into the large intestine the ileum is guarded by the _ileo-cecal valve_. - -[Illustration: FIG. 55.--1, Central lacteal; 2, capillary network; 3, -columnar cells.] - -The same _coats_ continue in the small intestine as were found in the -stomach, but they are here much thinner and the inner coat is shaggy, -like velvet, with innumerable minute processes called _villi_, which -greatly increase the absorbing surface. In fact, the great length of -the intestine as well as the presence of the villi is aimed to provide -a large surface to absorb the food as it passes, an even greater -increase of surface being provided by the fact that the intestinal wall -is thrown into folds, the _valvulæ conniventes_. Each villus is covered -with a layer of columnar epithelial cells and has within connective -tissue, in which are found a fine capillary network and open lymph -spaces from which leads a single lacteal vessel. - -Closely connected with the lymphatic vessels are the _solitary glands_, -small round bodies the size of a small pin’s head. _Peyer’s glands_ -or _patches_ are patches of solitary glands opposite the mesenteric -attachment and are largest and most numerous in the ileum. In typhoid -fever they are involved and may become the seat of ulcers. There are -also the _glands of Lieberkühn_ which secrete the succus entericus. - -The _arteries_ of the small intestine, which include the superior -mesenteric, are from the celiac axis and the _nerves_ are from the -superior mesenteric plexus of the sympathetic. The _veins_ empty -chiefly into the portal system. - -The _movements_ of the intestine, like those of the esophagus, are -peristaltic, but the action is complicated by the fact that the tube is -not straight but in coils. - -=Intestinal Digestion.=--The food, which enters the duodenum as chyme, -there comes in contact with the bile and the pancreatic juice, which -together but unmixed enter the duodenum from their respective ducts -by a common orifice. As in the stomach, the digestive juices are -called forth by the presence of food. The _bile_ is secreted in the -liver, from which it flows away through the hepatic duct, which joins -the cystic duct from the gall-bladder to form the common bile duct. -Through this it flows into the intestine during digestion, but between -whiles it passes up into the gall-bladder, where it is stored for -future use and whence it is expelled when needed. When pure it is a -thick, viscid liquid, varying from a bright red to a greenish-yellow in -color according to the pigments present, and of an alkaline reaction. -It consists chiefly of the bile pigments, _biliverdin_, which gives -the green color, and _bilirubin_, which gives the red color, and of -bile salts in solution, _cholesterin_, which probably forms the basis -of many gall stones, is also present. Bile is a disinfectant to the -bowel and a lubricant for the feces. How much digestive action it has -is a question, but it affords the necessary alkaline medium for the -pancreatic juice to act in. - -The _pancreatic juice_ is secreted by the pancreas, from which it -enters the intestine through the pancreatic duct, and is probably the -most important fluid in the digestive process. It is clear, practically -colorless, slightly viscid or gelatinous, and quite strongly alkaline -in reaction, owing to the presence of sodium carbonate. It contains -three ferments, _amylopsin_ for the digestion of starch, _trypsin_ for -the digestion of proteins, and _steapsin_ for the digestion of fats. -By it, as by the saliva, starch is turned into sugar or maltose, in -which form it is absorbed, while proteins are converted into peptones, -as they are in the stomach. Since, however, fats are acted on nowhere -else, the chief function of the pancreatic juice may be considered -to be the digestion of fats. Having broken through their albuminous -envelope, it divides them into glycerine and fatty acids and then -emulsifies them with the assistance of the bile. - -The food also comes in contact with the _succus entericus_, a juice -secreted by the glands of Lieberkühn in the small intestine, whose -chief action is the conversion of sugar into glucose. - -=Absorption.=--As the food is absorbed from the intestine it is -liquid and entirely digested and is known as _chyle_. Practically all -absorption takes place from the small intestine, though there is a -little in the large intestine. It takes place in two ways: 1. through -the portal vessels and 2. through the _lacteals_, which are the -lymphatic vessels of the small intestine. Fats are absorbed practically -entirely by the lacteals. They enter the cells covering the villi, -travel thence to the lymph spaces, and so into the lacteal or main -lymph channel, whence they are carried to the thoracic duct and the -general circulation. From the blood they are absorbed as fat and stored -up as adipose or fatty tissue, which is found throughout the body in -connective tissue about the organs. Organic salts and water are for -the most part absorbed by the portal system, which they reach through -the capillaries of the villi and through which they go to the liver. -Starches, in the form of sugar, pass between the cells of the villi -into the lymph spaces, from which they are taken up by the capillaries. -On the way to the liver maltose becomes dextrose. Proteins, in the form -of peptones, pass through the layer of epithelial cells to the lymph -spaces and then to the capillaries, an active part being taken by the -cells. By the time they reach the liver the peptones have been changed -back into proteins. In fact, peptones seem to have some poisonous -effect upon the blood if they get into it as such. - -=The Large Intestine.=--The large intestine differs from the small -in size and in fixity of position, lying curved in horseshoe shape -above and around the small intestine. It is five or six feet long, -large in caliber, and is thrown into crosswise folds. It has the same -four _coats_ as the small intestine, but the mucous coat is pale and -smooth, without villi. Its _glands_ are the crypts of Lieberkühn and -the solitary glands. The _arteries_ are branches of the superior and -inferior mesenteric and the _nerves_ come from sympathetic plexuses. - -The blind sac lying in the right iliac fossa, with which the large -intestine begins, is called the _cecum_, and into this the ileum -opens, the ileo-cecal valve preventing regurgitation. Just below the -ileo-cecal opening is the _vermiform appendix_, a narrow, worm-like -tube with a blind end, varying in length from one to nine inches, but -generally about four and one-half inches long, which, so far as is -known, is functionless as well as dangerous. People have been born -without an appendix and it has in rare instances grown again after -operation. Its base is located in the living by _McBurney’s point_, a -point two inches from the anterior superior spine of the ilium on a -line drawn from the spine to the umbilicus. - -From the cecum the intestine ascends in what is known as the _ascending -colon_ along the abdominal wall at the right to the under surface of -the liver, where it turns in the _hepatic flexure_ abruptly across -the body to the left, passing below the liver, stomach, and spleen -in the _transverse colon_. In the _splenic flexure_ it turns down -the left abdominal wall, the _descending colon_ passing to the crest -of the ilium, where there is another curve, the _sigmoid flexure_, -leading to the _rectum_, which passes for six or eight inches down -along the vertebræ, a little to the left, to the _anus_, the external -opening. This opening is guarded by two _sphincter muscles_, about an -inch apart, the internal and external sphincters. The coils of the -small intestine lie below the transverse colon, covered mostly by the -omentum. The splenic flexure is behind the stomach and below the spleen -and is slightly higher than the hepatic flexure. The sigmoid flexure -can be felt in the left inguinal region in thin people. - -The fact that the _rectum_ is somewhat to the left is of importance in -childbirth because if the rectum is packed, it may turn the child’s -head in the wrong direction. - -No digestion goes on in the large intestine, the function being to -dry by absorbing water. The _movements_ are practically the same -as those of the small intestine except that they are much less -active. Fermentation makes the contents acid. By the time food -reaches the rectum it has been thoroughly digested and has given up -its nourishment. It is then expelled as waste matter or _feces_. -_Defecation_ combines the involuntary movements of peristalsis and -relaxation of the sphincters with the voluntary aid of the abdominal -muscles. The _ano-spinal reflex_, by which movements of the bowel are -regulated, is in the lumbar enlargement of the cord. - -The _hemorrhoidal veins_ in the lower rectum are connected with both -the systemic and the portal veins and have no valves so that, as they -are subjected to much strain, they often become varicose and dilated. -This condition is called _hemorrhoids_ or _piles_. _Obstruction_ of -the intestine may be caused by the growth of a constricting band, by -_intussusception_ or telescoping of the intestine on itself, especially -at the ileo-cecal valve, or by _volvulus_ or twisting. _Foreign bodies_ -are sometimes found in the appendix but they are not usually the cause -of appendicitis. _Cancer of the intestine_ is common and its mass -is apt to cause obstruction with all its attendant symptoms. It may -necessitate an artificial anus. _Hernia_ or _rupture_ may also occur -and the hernia may become strangulated. - -=Food and Metabolism.=--Anything serves as food that replaces or -hinders the loss to which the component parts of the body are liable. -Proteins, carbohydrates, fats, some mineral matters, as salt and -perhaps iron, and water are needed. The energy once expended by plants -or animals in the formation of the materials which serve as food is set -free in the body by the breaking up of these complex substances into -their original elements, which are then recombined into the complex -materials needed for the body’s life and growth. This process of -building up complex materials from simple ones is known as _anabolism_ -and that of breaking them down as _katabolism_, while the two combined -form the complete cycle of _metabolism_. Those foods have the best -value that give up their energy most readily. For their combustion, -heat, oxygen, and water are needed. Hunger indicates that the supply of -material for katabolism has been used up and that more is needed, just -as thirst indicates the need of the system for more fluids. - -The proteins or nitrogenous foods include all animal foods except fats, -fish, crustaceans, eggs, milk and its products, certain vegetables, -especially the lentils, that is, peas and beans, and gelatine. The fats -include various fats and oils commonly eaten. The carbohydrates are -the starchy foods, as cereals, sugars, fruits, and most vegetables, -in fact, practically all except the lentils. Various beverages and -condiments have no great nutritive value but serve to stimulate the -appetite and to excite the secretion of the digestive juices. Coffee, -tea, and alcohol are stimulants. - -The different classes of foods have different functions in the -nourishment of the body. The proteins are primarily tissue-builders -and also help somewhat in force production. The fats are essentially -heat-producers, though they too help in force production. The -carbohydrates are chiefly important as force-producers, though they -also produce heat and to a certain extent save protein oxidation. Fat -is formed by all three but only in small amount by proteins. So no one -food can form the whole diet but there must be variety. Carbohydrates -and fats are not sufficient for life, some protein is necessary. -Carbohydrates are more digestible than fats but have less potential -energy. Gelatine saves waste of nitrogen, though it does not increase -the supply. Water and salts are not nutritive but they aid the body -processes, the water helping to dilute and dissolve substances for -digestion. - -The end-product of the consumption of protein is _urea_, which is -eliminated by the kidneys. Just where it is formed is unknown, but many -think in the liver. A trifling amount of urea is also eliminated in -the sweat and in the breath as well as in the feces. Proteins increase -nitrogenous metabolism and also the metabolism of other foods, but the -amount of nitrogen eliminated is just equal to that taken in. Probably -some comes from the tissues themselves and not from the food. The -oxidation of carbohydrates and fats is measured by the amount of carbon -excreted. At first as much is given off as is taken in, but after a -while the carbohydrate is stored up as glycogen in the liver and the -fats are stored as fat. - -The amount of food needed varies with the person’s size and occupation, -less being needed for a child than for an adult and more for a -hard-working man than for one who is doing less work. In general, 100 -to 130 grams of protein, 40 to 80 grams of fat, 450 to 550 grams of -carbohydrates, 30 grams of salts, and 28,000 grams of water is a fair -amount. - -Foods are cooked to make them more digestible and to develop their -flavor, so that they will taste better. Cooking also kills germs and -parasites that might be harmful. Meats should be cooked rapidly on -the outside to coagulate the surface albumen and keep in the juices. -The heat, besides coagulating the albumen, turns the tough parts to -gelatine. In cereals the tough envelope of cellulose is broken up -and in vegetables the tough fibrous parts are softened and made more -digestible. - -=The Liver.=--Below the diaphragm on the right and extending across -above the stomach, resting in a way upon the transverse colon and the -small intestine, is the liver, the largest gland in the body. It is -dark reddish-brown in color and is larger in proportion in the child -than in the adult. The upper surface is convex and lies in contact -with the diaphragm, while the lower surface is concave to fit over the -organs beneath. With a full breath it comes downward and forward, with -the edge against the abdominal wall, and can be easily felt. Numerous -strong ligaments, including the suspensory ligament from the diaphragm, -hold it in place, and it is more firmly fixed than any other of the -abdominal organs, probably on account of its large size. It is divided -by fissures into five _lobes_, of which the most important are the -right and left, the right one being the largest and containing the -gall-bladder in one of its fissures. - -[Illustration: FIG. 56.--The liver, seen from below. 1, Inferior vena -cava; 2, gall-bladder. (Morrow.)] - -The liver tissue contains a large number of _cells_ collected into -_lobules_, in the center of each of which is a blood-vessel, the -_intralobular vein_, from which a network of capillaries extends to -the edge of the lobule, there being a capillary on either side of each -row of cells. Between the cells also are the _intercellular biliary -passages_, roots of the bile ducts which exist in the connective tissue -between the lobules and which join to form two main ducts, one from -the right and the other from the left lobe. By the union of these two -ducts the _hepatic duct_ is formed, which, after a course of one or two -inches, joins the cystic duct from the gall-bladder to form the _ductus -communis_ or _common bile duct_. - -The liver has a double _blood supply_, the _hepatic artery_ from the -celiac axis bringing nourishment to the connective tissue and the walls -of the blood-vessels, while the capillaries between the cells come from -the _portal vein_, which, being formed by the junction of the superior -and inferior mesenteric, the splenic and the gastric veins, contains -the proteins and carbohydrates absorbed during digestion. After its -passage through the liver this blood from the portal vein is collected -once more into the hepatic veins, which convey it to the inferior vena -cava. During its passage, however, various changes take place, for the -liver plays an important part in the metabolic processes of the body. - -The liver has two principal _functions_, the secreting of bile and -the storing up of glycogen. The secretion of _bile_, which is a very -important aid to digestion, is probably a reflex act, the presence of -peptones in the portal blood after meals acting as a stimulant to the -liver cells. For food at once increases the secretion of bile, which -is poured from the cells into the small bile ducts and finally passes -into the hepatic duct and so to the gall-bladder, where it is stored -until needed. Although the flow from the liver is constant, the amount -secreted reaches its maximum when the food gets down into the small -intestine, that is, four or five hours after eating, there being a -lull before that. Apart from the process of secretion, the manufacture -of the bile pigments, _bilirubin_ and _biliverdin_, which are made from -the hemoglobin of the blood, seems to require some special action on -the part of the liver cells. - -The _glycogen_, which is manufactured and stored in the liver cells, -is a clear hyaline substance, akin to starch and capable of being -converted into sugar by the starch ferment. Probably there is some -such ferment in the blood which converts the glycogen into sugar as -soon as it passes from the liver into the blood, though what it is, -is not known. Neither is it known just how glycogen is formed, but -it is manufactured chiefly after a mixed meal in which carbohydrates -predominate, proteins having little and fats no effect upon its -formation. It is undoubtedly formed from the sugar in the portal blood -and the process requires some work on the part of the liver cell -itself. Probably there is always some sugar in the circulating blood -which, as it is used up, must be made good. If there it not enough in -the diet, the liver supplies the deficiency from its store of glycogen. - -Glycogen is found also in the muscles, in the placenta as food for the -fetus, in leucocytes, and to a slight extent in cartilage. In fact, it -is the form in which carbohydrate material is supplied to the tissues -as needed. Normally, much of the sugar is used up by the blood and -its cells in metabolism, giving rise to heat and energy. In muscles -glycogen is probably digested as lactic acid, as before action muscle -is neutral or slightly alkaline and after action acid. - -When the liver is deranged and allows the glycogen to pass out into the -blood too freely, or when the glycogen is not held as such but turned -to sugar and passed out in large quantities, _sugar in the urine_ or -_diabetes mellitus_ results. - -Besides its secreting function the liver has an _eliminative function_ -and plays an important part in purifying the blood, removing from -it many poisonous and narcotic substances. It is thought by some, -though it has not been proved, that _urea_, the end-product of protein -metabolism, which is brought by the blood to the kidneys and there -excreted, is formed in the liver. At any rate, urea is formed not only -from the nitrogenous food eaten but from the metabolism of protein -substances in the tissues, being purely a waste product, from which -the nutritious substances have been absorbed. The amount thrown off is -an accurate gauge of the amount of protein metabolism going on. The -process of its manufacture is doubtless very complex. - -_Ptosis_ or _dropping_ of the liver sometimes occurs and is due to the -stretching of the ligaments. _Rupture_ is common, generally as the -result of a fall from a height, on account of its size and friability. -The liver is also subject to many diseases. _Cirrhosis_ occurs in -people who drink a good deal and in its later stages is accompanied by -_ascites_, an accumulation of fluid in the abdominal cavity. When there -is a general accumulation of fluid throughout the body it is known as -_anasarca_. _Syphilis_ causes enlargement of the liver. _Abscesses_ -occur, perhaps oftener in the tropics than farther north, and may break -into the lungs, stomach, or intestine. - -=The Gall-bladder.=--The gall-bladder, which is simply a reservoir -for the bile, is a pear-shaped organ three inches long and one inch -broad. It lies in a fossa on the under side of the liver, with the -large end or fundus touching the abdominal wall just below the ninth -costal cartilage. Here it can be felt as a small mass in empyema of -the gall-bladder. Normally it holds a little over one ounce, but with -occlusion it may become stretched. Its duct is the _cystic duct_, which -joins the hepatic duct in the common bile duct, but bile only passes -up into the gall-bladder when the opening into the duodenum is closed, -that is, between meals. - -If one of the bile ducts is stopped up by a stone or cancer or for -any other cause, the bile backs up in the liver, the pigments are -absorbed into the circulation, and _jaundice_ results. In this -condition operation is dangerous, as the time of coagulation of the -blood, normally five minutes or less, is much delayed. _Gall stones_, -formed largely of bile pigments and cholesterin, sometimes collect in -the gall-bladder, where they cause irritation and may give rise to -_empyema_ of the gall-bladder. The stones vary in size from a pea to a -hen’s egg and when small may be very numerous. - -[Illustration: FIG. 57.--The pancreas, spleen, gall-bladder, etc., -showing their relations. (After Sobotta.)] - -=The Pancreas.=--Another accessory organ of digestion is the pancreas, -the _abdominal salivary gland_, as it is sometimes called on account -of its close resemblance to the parotid gland. This is a grayish-white -racemose gland, six and a half inches long by one and a half inches -wide and one inch thick, lying behind the stomach on a level with the -first and second lumbar vertebræ and shaped like a pistol with its -handle toward the right. In an emaciated person it can be felt. The -_pancreatic duct_ runs the whole length of the gland from left to right -and conveys the _pancreatic juice_ from various little glands in the -substance of the organ to the duodenum, into which it empties along -with the common bile duct by a common orifice. The _arteries_ are from -the celiac axis and superior mesenteric, the _veins_ belong to the -portal system, and the _nerves_ come from the solar plexus. - -Surgically the pancreas is of no special importance, though _acute -pancreatitis_ does occasionally occur and is a very serious condition -and one hard to diagnose. - -=The Spleen.=--The largest and most important of the ductless glands -is the spleen, an oblong, flattened organ lying deep in the left -hypochondriac region between the stomach and diaphragm above the -descending colon, and corresponding to the ninth, tenth, and eleventh -ribs. It is soft, brittle, and very vascular. Its _artery_ is a branch -of the celiac axis and the _vein_ belongs to the portal system. Its -_nerves_ are the pneumogastric and branches from the solar plexus. The -_function_ is not well understood but probably it is connected with or -related to the vascular system in some way. Perhaps it manufactures -blood corpuscles. - -The spleen varies more in size than any other organ. Normally it cannot -be felt, but in typhoid it usually can. It is generally atrophied in -old age and hypertrophied in almost all acute infectious diseases, -especially in typhoid fever and malaria. In leukemia it is often -greatly enlarged. Sometimes in violent falls it is _ruptured_ and there -is considerable hemorrhage. - -=The Suprarenal Capsules.=--The other ductless glands, the suprarenal -capsules, yellowish triangular bodies, are situated just above and -in front of the kidneys. Their function is important but not well -understood. Death, accompanied by great muscular weakness, follows -the removal of both, and when they are diseased, similar weakness is -observed and the skin becomes bronzed. Injection of the extract of -the suprarenals stimulates the muscular system. So probably they -secrete into the blood minute quantities of a substance or substances -beneficial to the body, especially to the muscular system. - -[Illustration: FIG. 58.--Diagram of the relation of kidney to viscera, -spine, and surface points. (American Text-Book of Surgery.)] - -=The Kidneys.=--The two kidneys lie on either side of the vertebræ at -the back of the abdominal cavity and behind the peritoneum, between the -last dorsal and the third lumbar vertebræ, their inner edge being about -one inch from the spinous processes. They are bean-shaped, four inches -long, two inches wide, and one inch thick, and are embedded in a mass -of fat and loose areolar tissue. They can be felt only when misplaced -or when enlarged, as by tuberculosis or malignant disease. - -The whole kidney is enveloped in a fibrous _capsule_ which normally -may be peeled off but which in some diseases becomes adherent. On the -internal border is a _fissure_ or _hilum_, through which pass the -blood-vessels and the ureter. Upon entering, the ureter dilates into -a sac, the _pelvis of the kidney_, into which project the _Malpighian -pyramids_ of the _medullary substance_, a substance made up of the -straight uriniferous tubules and blood-vessels. Outside the medullary -substance and just under the capsule is the _cortex_, containing the -_Malpighian bodies_, blood-vessels, and the _convoluted tubules_ or -_loops of Henle_. Each Malpighian body contains within a capsule a -plexus of capillaries, the _glomerulus_, with an afferent arteriole and -an efferent vein. The _renal artery_ is a branch of the aorta and the -_nerves_ are from the solar plexus. - -[Illustration: FIG. 59.--A longitudinal section of the kidney. (Leroy.) -_a_, Renal artery; _c_, cortex; _m_, medulla; _u_, ureter.] - -[Illustration: FIG. 60.--A Malpighian body or corpuscle. (Leidy.) -_a_, Afferent artery; _e_, efferent vessel; _c_, capillaries; _k_, -commencement of uriniferous tubule; _h_, uriniferous tubule.] - -_The Urine._--As the blood passes through the glomeruli, the urine is -filtered off as it were, probably by a process of transudation rather -than simple filtration. The cells lining the tubules also play an -important part in its formation, not by secreting new substances but -by taking up those brought by the blood and discharging them into the -convoluted tubules, from which the urine passes through the straight -tubules of the medulla to the pelvis, to be carried thence by the -ureter. The process of the formation of the urine, therefore, is not -purely a process of secretion but requires some action on the part of -the kidney, though no new substances are secreted in the kidney. - -The passage of the urine down through the ureters is assisted by a kind -of peristaltic action in the walls of the ureters and it is expelled -from the body by the act of _micturition_, which is mostly voluntary, -though a certain amount of nervous mechanism controls it. The seat of -this nervous mechanism is in the lumbar enlargement of the spinal cord. -In some nervous conditions, especially where there is injury to the -spinal cord, there is _involuntary micturition_. - -The urine is a watery solution containing many waste products, -especially urea. It is generally amber in color, varying in shade with -circumstances, with an aromatic, characteristic odor when fresh. It -is acid in reaction and has a specific gravity of about 1020, though -this too varies with circumstances. Besides water, which is its chief -constituent, it contains urea, uric acid, organic acids, urates, -inorganic salts, including sodium chloride and phosphates of calcium -and magnesium, a certain amount of ammonia, and certain pigments. Its -acidity is due to acid sodium phosphate in solution but varies with the -food, and in disease the urine may become alkaline when passed. After -standing a few hours in a warm place it decomposes and becomes alkaline. - -The quantity, which is normally three pints or fifteen hundred cubic -centimeters in twenty-four hours, varies with the amount of fluid -drunk, the amount of perspiration, etc. The amount secreted depends -chiefly, however, upon the flow of the blood through the kidneys; the -greater the flow of blood, the larger the amount of urine formed; and -the blood flow is determined by blood pressure and by vasomotor action. -Secretion also seems to be increased by the presence of urea, which -apparently serves as a stimulant to the kidney cells. - -The excretion of waste materials takes place by three main channels, -the lungs, skin, and kidneys, and the materials are of four kinds, -_urea_, _carbon dioxide_, _salts_, and _water_. The lungs carry off -carbon dioxide and water chiefly, the skin these and inorganic salts, -while the kidneys eliminate practically all the urea as well as -inorganic salts and water. When the kidneys are not working the skin -carries off much urea. In fact, a close relationship exists between the -kidneys and the skin in the matter of excretion. Thus, with increased -perspiration in warm weather comes decreased urine, while in cold -weather the blood is sent in and the urine increased in amount. - -To incite action of the kidneys drugs known as _diuretics_ may be used. -These act in two ways, by stimulating the kidney cells directly and by -acting on the general circulation or nervous system. Any emotional or -nervous excitement increases the flow of urine. - -There are certain abnormal constituents of urine, of which the two most -important are _albumen_ and _sugar_. The former is found only when -there is some disturbance of the kidneys, ureters, or bladder, and its -presence usually denotes some change in the cells lining the urinary -tract. It may occur in congestion of the kidney as well as in disease. -Sugar is found only in _diabetes_, the amount varying with the severity -of the disease. In _jaundice_ certain bile pigments are present in the -urine, giving it a dark brown color and to the foam a greenish-yellow -color. Even normal urine has some sediment upon standing, consisting -of cells from the urinary tract and mucus. In very acid urine after -standing a heavy sediment, whitish or pinkish, _i.e._, brick dust, in -color, is thrown down. It does not necessarily denote disease, but -shows the urine is acid and concentrated. In _alkaline urine_ there is -a sediment due to phosphates. - -_Rupture_ of the kidney occurs but is not so serious as rupture of -the liver or spleen because the kidney is situated outside of the -peritoneum. It necessitates the removal of the kidney, however, and -when for any reason one kidney is removed the other increases in size -and does double work to compensate for the loss. Removal of both -kidneys means death. Sometimes the kidney becomes loose and moves -about, a condition known as _floating kidney_. _Perinephritic abscess_ -is abscess in the loose fatty tissue about the kidney. - -[Illustration: FIG. 61.--The urinary organs viewed from behind.] - -=The Ureters=, one for each kidney, are tubes the size of a goose -quill and about fourteen inches long, extending from the hilum of the -kidney to the base of the bladder. They have three _coats_, an internal -mucous, a muscular, and an external fibrous coat, this last being -continuous with the cortex of the kidney and the fibrous tissue of the -bladder. In the female the ureters may be felt through the wall of the -vagina as they come into the bladder. In tubercular disease of one -kidney the ureter becomes inflamed and enlarged and through the vagina -feels almost like a lead pencil, a sure diagnostic sign. - -=The Bladder and Urethra.=--In their course to the bladder the ureters -pass from the abdominal into the pelvic cavity, but before describing -the pelvis itself it will be well to complete the account of the -urinary organs by considering the bladder and urethra. The _bladder_ is -the reservoir for the urine and has muscular walls lined with mucous -membrane. A peritoneal coat covers the upper surface and is reflected -to the walls of the abdomen and pelvis. It is situated back of the os -pubis, the front bone of the pelvis, with its base or fundus directed -downward and backward. Normally it is in the pelvis, but when much -distended it mounds up into the abdominal cavity, where it can be -felt in front as a tumor. It rests on the rectum in the male and on -the cervix in the female and is held in place by numerous ligaments. -When empty it may be Y-shaped, but it becomes oval when distended. Its -capacity is about one pint. - -The lower abdominal wall and the anterior wall of the bladder may be -wanting congenitally. In paralysis of the sphincter at the neck of the -bladder distention results. _Stones_ may be found in the bladder. - -From the neck of the bladder the urine passes out of the body through -the _urethra_. This in the male passes down through the penis and is -about ten inches long. Except when urine is passing it is a transverse -slit with the upper and under surfaces in contact, while at the end of -the penis the slit of the meatus urinarius is vertical. When the penis -is flaccid, the urethra describes a sharp curve before its entrance -into the bladder, but it becomes approximately straight when the penis -is raised at right angles to the body--an important point to remember -in catheterization. - -In the female the urethra is straight and much shorter, being only -about one and a half inches long. The _meatus urinarius_ is in the -anterior vaginal wall about one inch behind the clitoris. - -Sometimes the urethra is _ruptured_ in a fall. _Stricture_ of the -urethra occurs sometimes after gonorrhoea, owing to the formation of -scar tissue following ulcer. - - - - -CHAPTER XI. - -THE PELVIS AND THE GENITAL ORGANS. - - -=The Pelvis.=--Before taking up the pelvic organs, the pelvis itself -should be described. The name pelvis has been given to the bony ring -which is interposed between the spine and the femurs on account of its -resemblance to a basin. At the back of this basin or pelvis are the -_sacrum_ and _coccyx_, already described in connection with the back, -and at the sides and meeting in the median line in front are the two -_ossa innominata_ or _nameless bones_, so called on account of their -peculiar and indescribable shape. At birth each os innominatum is made -up of three bones, the _ilium_, _ischium_, and _pubes_, but about the -age of puberty the three become welded into one. At their point of -junction is the cavity of the acetabulum for articulation with the head -of the femur or thigh bone. - -[Illustration: FIG. 62.--Front view of the pelvis, with its ligaments. -(Dorland.) _a_, Anterior sacro-iliac ligament; _b_, iliofemoral -ligament; _c_, obturator membrane; _d_, symphysis pubis; _e_, -sacro-sciatic ligament.] - -[Illustration: FIG. 63.--The right innominate bone. (After Toldt.)] - -The upper, expanded portion of the os innominatum is the _ilium_, -whose upper border is known as the _crest_ and which has two _spinous -processes_ front and back, a superior and an inferior, the superior -spine being in each case the larger. These spines, especially the -anterior superior spines, and the crest give attachment to many -muscles, and to the outer surface of the bone the gluteal muscles are -attached. The anterior superior spine is also important in making -measurements to ascertain whether both legs are of equal length. - -Below the ilium posteriorly is the _body of the ischium_, which has on -its lower edge a tuberosity, the prominent bone on which one sits. Near -the upper edge is the _spine_ of the _ischium_, between which and the -posterior inferior spine of the ilium is the greater _sacro-sciatic -notch_ for the passage of vessels and nerves, including the sciatic -nerves. From the tuberosity the ramus extends forward below the -_obturator foramen_, a large opening between the ischium and the pubes, -also for the passage of vessels and nerves, to meet the pubes, the last -and smallest of the three bones which go to make up the os innominatum. - -The anterior surface of each _pubes_ presents a crest, ending -externally in a spine, and the two pubic bones join in front in the -_symphysis pubis_. The bone gets its name from the growth of pubic -hairs over this region at puberty. - -[Illustration: FIG. 64.--Diameters of the pelvis: _d_, antero-posterior; -_o b_, oblique; _t r_, transverse. (de Nancrede.)] - -Anteriorly the ossa innominata support the external organs of -generation, while within are the internal organs of generation. On the -inner surface of the ilium, slightly above the level of the acetabulum, -is the _ileo-pectineal line_, above which lie the _iliac fossæ_. A -plane drawn through the prominence of the sacrum, the ileo-pectineal -lines, and the upper margin of the symphysis pubis serves to divide -the upper or false pelvis from the lower or true pelvis. The _false -pelvis_, which is the larger, serves to support the intestines and -to take part of the weight from the abdominal walls, while the _true -pelvis_, being more surrounded by bone and so capable of affording -more protection, guards the internal organs of generation. The lower -circumference of the pelvis is known as the _outlet_. In the female the -bones are lighter, the sacrum less curved, and the diameters greater -than in the male. - -On the whole, the pelvic bones are well covered in with muscles. The -anterior superior spine, however, is easily felt in front and the whole -crest can be felt back to the posterior superior spine. The tuberosity -of the ischium also can be felt, especially when the thigh is flexed, -for it is largely uncovered of muscles. The spine of the os pubis can -always be felt, on a level with the great trochanter, and the relation -of its position to that of a hernia shows whether the rupture is above -or below Poupart’s ligament, that is, whether it is inguinal or femoral. - -Occasionally there is lack of development of the pubic bones for two -or three inches and the bladder is exposed. _Fracture_ of the pelvis -may occur, perhaps with injury to the viscera. The acetabulum may -be fractured or the sacrum broken, with injury to the sacral plexus -of nerves, causing paralysis of the lower extremities and of the -sphincters, with resultant involuntary passage of urine and feces, and -in childbirth the coccyx is often broken. In _rickets_ there may be -great deformity of the pelvis, causing trouble in childbirth later in -life. _Osteomalacia_ is a disease of adults, in which the bones are -soft and the weight pushes the promontory of the sacrum forward and -approximates the sides of the pelvis. - -=The Male Generative Organs.=--The male generative organs consist of -the prostate gland, testes, and penis. - -The _prostate gland_ is shaped like a small horse-chestnut and is -composed of numerous glands from which come a dozen or more excretory -ducts. It surrounds the neck of the bladder and the beginning of the -urethra and is next to the rectum, through which an examination may be -made to determine its size. For it often enlarges in elderly men, the -frequent passage of urine in small amounts being a symptom of enlarged -prostate. - -The _procreating glands_, which secrete the spermatozoa or semen, are -two in number, the _testes_ or _testicles_, and are homologous to the -ovaries in the female. They are ovoid in form and are suspended by the -_spermatic cords_ in a sac, the _scrotum_, back of the penis. During -early fetal life they are in the back of the abdomen near the kidneys, -but before birth they descend along the inguinal canals into the -scrotum. The excretory duct of the testis is called the _vas deferens_. -It passes up by the spermatic cord through the inguinal canal into -the pelvis to the base of the bladder and at the base of the prostate -joins the duct of the vesicula seminalis to form the _ejaculatory -duct_. The two _vesiculæ seminales_ are small receptacles for the semen -lying in contact with the base of the bladder and secrete a fluid with -which they dilute the semen. The ejaculatory duct terminates near -the prostate in the urethra by a slit-like orifice on each side, the -spermatozoa being finally excreted through the urethra. - -The _penis_ is the external organ of generation in the male and is -attached to the pubes and the anterior part of the ischium. It is -composed of erectile tissue and encloses the urethra, the _meatus -urinarius_ appearing at its end as a vertical slit. Toward the end the -skin of the penis is loose and is prolonged forward in what is known -as the _prepuce_ or _foreskin_. It is this that is clipped away in -circumcision. - -=The Female Generative Organs.=--The female generative organs include -the ovaries, Fallopian tubes, uterus, vagina, and the external -genitalia or vulva. - -The _ovaries_, which are homologous to the testes in the male, are -two flattened oval bodies, grayish pink in color, suspended from the -lateral or broad ligaments which fasten the uterus to the walls of the -pelvis. They are one and a quarter inches long, three-quarters of an -inch wide, and half an inch thick and are attached at the upper end to -one of the fimbriæ of the Fallopian tubes. They consist of numerous -_Graafian follicles_ embedded in a fibrous stroma, each follicle -containing an _ovum_ about ¹/₁₂₅ inch in diameter and just visible to -the naked eye. When a follicle ruptures and discharges an ovum, an -irregular yellow spot, the _corpus luteum_, appears at the point of -rupture. After ordinary menstruation it is known as the _false corpus -luteum_ and after conception as the _true_ one, this one being larger -and lasting longer. - -[Illustration: FIG. 65.--View of the pelvis and its organs. (Savage.) -_B_, Bladder; _U_, uterus (drawn down by loop _e_); _F_, Fallopian -tubes; _O_, ovaries; _L_, round ligaments; _g_, ureter; _a_, ovarian -vessels, often prominent under their peritoneal covering; _R_, rectum; -_V_, vertebra.] - -The _Fallopian tubes_ are the oviducts and convey the ova from the -ovaries to the uterus. They are four inches long and lie between the -layers of the broad ligaments, opening into the uterus by an orifice -the size of a bristle, while the end next to the ovary spreads -out trumpet-like and is edged with _fimbriæ_ as with a fringe, the -fimbriated extremity. There are three _coats_: a serous coat which is -continuous with the peritoneum, a muscular coat, and, within, a mucous -coat covered with cilia, continuous with the mucous membrane of the -uterus. One fimbria is attached to the ovary and as the ovum is given -off it finds its way into the tube and thence to the uterus. - -[Illustration: FIG. 66.--Sagittal section of the female pelvis. -(Dickinson.)] - -The _uterus_ is a pear-shaped organ, about three inches long, two -inches broad above, and one inch thick, situated in the pelvic cavity -between the rectum and the bladder. The wide part or _fundus_ is -above and the narrow neck or _cervix_ below, lying partly within the -vagina. The whole is held in place by ligaments. These include the -_broad ligaments_, which extend from the sides of the uterus to the -lateral walls of the pelvis, and the _round ligaments_, two muscular -cords, about four inches long, which pass out through the abdominal -ring into the inguinal canal and so to the mons veneris and labia, thus -corresponding to the spermatic cords in the male. The cavity of the -body of the uterus is small and flattened and opens into the cervix by -the _internal os uteri_, the _external os_ being at the opening of the -cervix into the vagina. There are three _coats_: a serous coat derived -from the peritoneum, a muscular coat of unstriped fibers which forms -the bulk of the whole organ, and a mucous coat covered with ciliated -epithelium. - -The uterus is always enlarged during menstruation and is enormously -enlarged in pregnancy. It receives the fecundated ovum, retains and -supports it during the development of the fetus, and is the chief agent -of expulsion. In _tubal_ or _extra-uterine pregnancy_ the ovum becomes -attached in the tube instead of in the uterus, and develops there, -rupturing the tube and causing serious hemorrhage. - -The passage from the cervix out of the body is the _vagina_, a -membranous canal, curved upward and backward to conform to the axis of -the pelvis, and attached above to the cervix. Ordinarily the sides are -in contact. - -The _arteries_ of the internal organs of generation are the uterine -from the internal iliac and the ovarian from the aorta in the female, -the pudic branches of the internal iliac and the spermatic from the -aorta in the male. The _nerves_ are largely from the sympathetic system. - -_Abscess formation_ occurs frequently in the tubes and _gonorrheal -infection_ may spread up the vagina and through the uterus to the -tubes, and even to the abdominal cavity itself. The tubes may also be -_tubercular_. - -_Salpingectomy_ or removal of the tubes is the commonest operation -after that for appendicitis. _Cancer_ of the uterus may necessitate -_panhysterectomy_ or removal of the uterus and all its appendages. - -[Illustration: FIG. 67.--Virginal vulva. (Modified from Tarnier.) 1, -labia majora; 2, fourchette; 3, labia minora; 4, glans clitoridis; 5, -meatus urinarius; 6, vestibule; 7, entrance to the vagina; 8, hymen; -9, orifice of Bartholin’s gland; 10, anterior commissure of labia -majora; 11, anus; 12, blind recess; 13, fossa navicularis; 14, body of -clitoris.] - -The _external genitalia_ in the female, as in the male, are situated -over the pubic arch. They are known as the _vulva_ and include the -mons Veneris, the labia majora and minora, the vaginal orifice, the -clitoris, and the meatus urinarius. - -The _mons Veneris_ is a rounded eminence composed of fatty tissue, -which surmounts the pubic bones and is covered with hair at puberty. -From it two prominent longitudinal folds of skin, covered with hair -on the outside, the _labia majora_, extend backward, forming the -lateral boundaries of the vulva. Within these labia again are two -thin cutaneous folds, the _labia minora_ or _nymphæ_, which run back -from the clitoris for about one and a half inches and enclose the -_vaginal orifice_. The _clitoris_ corresponds to the penis and is -just above the upper part of the labia minora. Between it and the -vagina is the _meatus urinarius_. The orifice of the vagina is partly -closed in the virgin by the _hymen_, a thin fold of mucous membrane, -which occasionally closes it completely, _imperforate hymen_. The -_fourchette_ is a small transverse fold of skin at the junction of the -labia minora posteriorly. Between the vagina and the rectum is the -_perineal body_, a somewhat triangular structure made up of many small -muscles. Its surface is known as the _perineum_. It is frequently torn -wholly or in part during childbirth and has to be sewed up. - - - - -CHAPTER XII. - -THE UPPER EXTREMITIES. - - -The upper extremities include the shoulders, arms, forearms, wrists, -and hands and contain each thirty-two bones. The bones of the two -shoulders taken together are called the _shoulder girdle_ and consist -of the two clavicles or collar bones and the two scapulæ or shoulder -blades, which together make an almost complete girdle of the shoulders. - -The =clavicle= is a long slender bone extending almost horizontally -from the sternum to the scapula and can be felt for its whole length -in the living. For the inner two-thirds it is convex anteriorly, -for the outer third concave. In woman it is generally less curved, -smoother, and more slender than in man, and as bone is rough when the -muscles attached are powerful, the right clavicle, being used more, is -generally rougher and thicker than the left. Among the muscles attached -are the large neck muscle, the _sterno-cleido-mastoid_, whose tendons -form the _presternal notch_, the _trapezius_, the _pectoralis major_, -and the _deltoid_. - -Being slender and superficial the clavicle is most frequently _broken_ -of any bone in the body, generally by indirect violence, as by falling -with the hand out, though old people in such a case are apt to get -_Colles’ fracture_ at the wrist. The bone generally gives way at the -juncture of the outer and middle thirds, with displacement of the -parts inward, so that the fracture is seldom compound. Since, however, -the main vessels of the upper arm, with their nerves, lie beneath the -clavicle, there is danger of their being punctured. Such serious injury -is guarded against by the presence of the _subclavius muscle_. The -clavicle is occasionally removed for _sarcoma_. - -[Illustration: FIG. 68.--Bones of the upper extremity. (Toldt.)] - -[Illustration: FIG. 69.--Left scapula, posterior surface (after Toldt).] - -The =scapula= or =shoulder blade=, so called from its shape, is a -large, flat, triangular bone with a prominent ridge, the _spine_, -crossing its dorsum or posterior surface near its upper edge. It -extends from the second to the seventh rib, with its posterior margin -parallel to and about one inch from the dorsal vertebræ. The _head_, -in which is situated the _glenoid cavity_ for articulation with the -humerus or upper arm bone, is surrounded by a slight constriction, -the _neck_. Above it projects the _coracoid process_, so called from -its fancied resemblance to a crow’s beak. This can usually be felt -about one inch from the juncture of the outer and middle thirds of -the clavicle and from it arise the short head of the biceps and the -coraco-brachialis muscle. The _acromion process_ at the end of the -spine extends out beyond the glenoid cavity posteriorly and affords -attachment to the deltoid and trapezius muscles. It forms the summit -of the shoulder. Numerous other muscles are attached to the surface -of the scapula, the only parts which are truly subcutaneous being the -whole length of the spine and the acromion process, though the lower -angle and the coracoid process can generally be felt. The muscles bulge -so much that the spine in the living appears as a slight depression -extending back almost to the vertebræ. The large number of the muscles -on the shoulder and arm is due to the great flexibility and strength -required for the various uses to which the arms are put. - -=Shoulder Muscles.=--The most important shoulder muscle is the -_deltoid_, a large triangular muscle, which surrounds and protects -the shoulder-joint and gives the shoulder its rounded form. It rises -from the outer third of the clavicle, from the acromion process, and -from the whole length of the spine of the scapula, and is inserted -by a tendon into a rough prominence on the middle of the outer side -of the humerus. It serves to raise the arm and to draw it somewhat -forward or back, according as the anterior or posterior fibers are -used. The _pectoralis major_ rises from the inner half of the clavicle, -the front of the sternum, and the cartilages of the true ribs and its -fibers converge to form a fan-shaped muscle, which is inserted by a -flat tendon into the edge of the bicipital groove on the humerus. It -draws the arm forward and inward and helps considerably in forced -inspiration. The _serratus magnus_ rises from the outer surface and -upper border of the eight upper ribs and from an aponeurosis covering -the upper intercostal spaces, and is inserted along the whole length of -the posterior border of the scapula. It carries the scapula forward and -is used in pushing. - -The scapula is seldom _broken_ because it is quite movable and is -covered with large muscles and because it lies on the chest, which -serves as an elastic cushion. The acromion process is the part most -frequently broken and occasionally the neck is fractured. _Tumors_ -occur and may necessitate the amputation of the whole upper extremity. - -=The Humerus.=--The bone of the upper arm, the humerus, is the largest -bone in the upper extremity and articulates with the scapula above -and with the ulna and radius below. At its upper end are the _head_ -and the _anatomical neck_, with the _greater tuberosity_ external to -and the _lesser tuberosity_ in front of them. The constriction of the -surgical neck is below the tuberosities, and extending from between -them downward and inward along the upper third of the bone is the -bicipital groove for the long head of the biceps. Though round above, -below the _shaft_ becomes flattened from before backward and curves -slightly forward, terminating in the internal and external _condyles_, -from the former of which the flexors and the round pronator arise and -from the latter the extensors and supinators. From the external condyle -also there projects in front the _radial head_ or _capitellum_ for -articulation with the radius. Internally to the capitellum in front and -in a corresponding position on the back of the bone are the trochlear -surfaces for articulation with the ulna, there being a depression in -front called the _coronoid fossa_ for the reception of the _coronoid -process_ of the ulna in flexion of the forearm, and another depression -behind, the _olecranon fossa_, to receive the tip of the olecranon -process during extension. On the lower half of the humerus at the back -is the spiral groove for the _musculo-spiral nerve_ and the _superior -profunda artery_, while the _ulnar nerve_ runs in a groove back of the -internal condyle. - -The humerus is almost completely covered with muscles, the only -part that is subcutaneous being a small portion of the external and -internal condyles. The head can be felt under the muscles and the -greater tuberosity forms the point of the shoulder. When the arm is -at the side, the biceps appears at the front and inner side and the -brachialis anticus on either side below, while on the back of the arm, -with its largest swelling above, is the triceps. - -[Illustration: FIG. 70. - -FIG. 70.--Superficial muscles of shoulder and arm (from before): 1, -Pectoralis major; 2, deltoid; 3, biceps brachii; 4, brachialis anticus; -5, triceps; 6, pronator radii teres; 7, flexor carpi radialis; 8, -palmaris longus; 9, flexor carpi ulnaris; 10, supinator longus; 11, -extensor ossis metacarpi pollicis; 12, extensor brevis pollicis; 13, -flexor sublimis digitorum; 14, flexor longus pollicis; 15, flexor -profundus digitorum; 16, palmaris brevis; 17, abductor pollicis. -(Dorland’s Dictionary.)] - -[Illustration: FIG. 71. - -FIG. 71.--Superficial muscles of shoulder and arm (from behind): 1, -Trapezius; 2, deltoid; 3, rhomboideus major; 4, infraspinatus; 5, -teres minor; 6, teres major; 7, latissimus dorsi; 8, triceps; 9, -anconeus; 10, brachialis anticus; 11, supinator longus; 12, extensor -carpi radialis longior; 13, extensor carpi radialis brevior; 14, -extensor communis digitorum; 15, extensor carpi ulnaris; 16, flexor -carpi ulnaris; 17, extensor ossis metacarpi pollicis; 18, extensor -brevis pollicis; 19, tendon of extensor longus pollicis. (Dorland’s -Dictionary.)] - -=Upper Arm Muscles.=--The _biceps_ is the most important arm muscle. It -rises by a short head from the coracoid process of the scapula and by -a long head from a tubercle on the upper margin of the glenoid cavity, -the tendon arching over the head of the humerus and descending in the -bicipital groove. It is inserted into the back of the tuberosity of -the radius and by a broad aponeurosis into the fascia of the forearm. -It flexes and supinates the forearm and renders the fascia tense. Its -inner border forms a guide in tying the _brachial artery_, as this -artery runs along its inner side. - -The _brachialis anticus_ rises from the lower half of the outer and -inner surfaces of the humerus and is inserted into the coronoid process -of the ulna, thus covering and projecting the elbow-joint anteriorly. -It is a flexor of the forearm. - -Another smaller muscle on the anterior arm, which also aids in flexion, -is the _coraco-brachialis_, which extends from the coracoid process of -the scapula to the middle of the inner surface of the humerus. - -Extending the entire length of the posterior surface of the humerus -is the _triceps_, similar to the quadriceps extensor in the thigh and -direct antagonist to the biceps and brachialis anticus muscles. It -rises by a long head from below the glenoid fossa, by the external head -from the upper third of the posterior surface of the humerus, and by -the internal head from the middle and lower thirds of the posterior -surface. It is inserted in the olecranon process of the ulna and serves -to extend the forearm and arm. - -The humerus is more often _fractured_ by muscular action than any -other bone. Usually the fracture occurs in the lower half of the -bone and sometimes the musculo-spiral nerve is involved. There is a -great tendency to non-union, probably due to interposition of soft -parts. Sometimes the break is across and down between the condyles, -_T-fracture_. Involvement of the elbow-joint is more serious than -fracture of the humerus alone. _Sarcoma_ of the humerus does occur and -may require the removal of the clavicle and scapula as well as of the -arm bone itself. In _amputation_ of the humerus in children a long skin -flap is left to allow for growth of the bone, as it is liable to grow -again. - -=The Ulna.=--In the forearm there are two bones, the ulna and the -radius, of which the former is the longer. The ulna is on the inner -side of the forearm and its upper end forms the greater part of the -articulation with the humerus, as most of the articulation at the wrist -is formed by the radius and the inter-articular fibro-cartilage. The -head of the ulna is at the lower extremity of the bone and articulates -on the outer side with the radius and below with the triangular -fibro-cartilage. From its inner side projects the _styloid process_. -The olecranon process forms the upper extremity and presents anteriorly -an articular surface, the _greater sigmoid cavity_, for articulation -with the trochlea of the humerus, where it fits into the olecranon -fossa during extension. The same articulating surface also covers -the _coronoid process_, a smaller projection below and in front of -the olecranon, which fits into the coronoid fossa during flexion. -Continuous with the greater sigmoid cavity on the outer side is the -_lesser sigmoid cavity_ for articulation with the head of the radius. -Under the _triceps tendon_, which is inserted into the olecranon, is a -_bursa_ or sac of synovial membrane, such as occurs in parts where much -force is brought to bear. - -=The Radius.=--The radius, or spoke of the wheel, is on the outer -side of the forearm and gets its name from the way it turns upon -the ulna in pronation. The _shaft_ is larger below than above and -is slightly curved longitudinally for greater strength. The upper -extremity or _head_ is small and has a slightly concave upper surface -for articulation with the radial head of the humerus. It articulates by -its sides with the lesser sigmoid cavity and is bound to the ulna by -the _orbicular ligament_, which runs over a smooth articular surface. -Below the head is the constriction of the _neck_ with the tuberosity -for the biceps tendon to the inner side below. The lower extremity is -large and forms the chief part of the wrist-joint, articulating with -the semilunar and scaphoid bones of the wrist. From the lower extremity -the strong conical _styloid process_ projects externally. - -[Illustration: FIG. 72.--Bones of the right forearm in a position of -supination. (Toldt.)] - -In the living the _olecranon process_ of the ulna is always felt at -the elbow and the posterior border of the ulna forms the prominent -ridge down the forearm, leading to the styloid process. The head of -the radius is felt just below the external condyle and often makes a -dimple in the muscles of the forearm. The rest of its upper half is -concealed with muscles, but the lower half is easily felt as there are -only tendons over it. The styloid process is felt externally. Normally -that of the radius is a little lower than that of the ulna, so that in -cases of fracture their relative position is of considerable importance -as showing the amount of deformity. - -The two forearm bones are more frequently _broken_ together than -separately and generally by direct violence, the lower fragment being -usually drawn up by the action of the flexor and extensor muscles and -producing a swelling on the palmar surface of the forearm. Indirect -violence usually causes fracture of the radius only. In both cases, but -especially in fracture of both bones, there is a tendency for membrane -to get between the fragments, so the arm is put up in splints with the -hand midway between pronation and supination in order to separate the -bones as far as possible. Care must be taken not to have the bandage -too tight or gangrene of the fingers may result. In most fractures of -the arm it is put up bent, but in _fracture of the olecranon_ it is put -up fully extended, as the fragment is sure otherwise to be displaced by -the pull of the triceps. In fact, the olecranon is sometimes fractured -by the muscular force of the triceps, though usually its fracture, -which is frequent, is due to direct violence. The ulna is also often -fractured in the middle by direct violence or the styloid process may -be broken. Fracture of the neck or shaft of the radius is very common, -the most important arm fracture being that of the lower end of the -radius or _Colles’ fracture_. This and the corresponding fracture in -the leg, _Pott’s fracture_, are two of the commonest fractures. In -_dislocation of the wrist_ the normal relation of the two styloid -processes remains unchanged, but in Colles’ fracture the lower fragment -often projects on the back of the hand, making a typical deformity -called the _silver fork deformity_. - -The bones of the wrist and hand had best be described before the -forearm muscles are taken up, as the muscles of the forearm are -distributed largely to the fingers. - -=The Wrist.=--The wrist or _carpus_ is made up of eight bones arranged -in two rows of four each. In the first row are the _scaphoid_ and -_semilunar bones_, on the outer side, articulating with the radius, the -_cuneiform_ articulating with the fibro-cartilage of the wrist-joint, -and the _pisiform_. In the second row, in corresponding positions, -are the _trapezium_, _trapezoid_, _os magnum_, and _unciform_. The -eminence felt on the radial side of the wrist is the protuberance of -the scaphoid, while the pisiform is generally felt on the ulnar side. - -[Illustration: FIG. 73.--Right carpal bones, dorsal surface. _T_, -trapezium; _T´_, trapezoid; _7_, os magnum; _U_, unciform; _S_, -scaphoid; _L_, semilunar; _C_, cuneiform; _P_, pisiform.] - -=The Hand.=--The hand contains nineteen bones, five _metacarpal bones_, -one for each finger and the thumb, whose bases articulate with the -lower row of wrist bones, and fourteen _phalanges_, three for each -finger and two for the thumb, of which the first row articulate with -the metacarpal bones. They are all long bones and are slightly concave -anteriorly. When the hand is flexed it is the heads of the metacarpal -bones, not the bases of the phalanges, that are so prominent, the head -of the third metacarpal being most prominent. - -The metacarpals are seldom _fractured_, though bad fractures -occasionally occur. In comminuted fracture nothing can be done but -remove the bone. If the periosteum is left the bone will grow again. -Two diseases sometimes affect the metacarpals and the phalanges, -_tuberculosis_ and _syphilis_. Both cause swelling of the bones. - -=Muscles of the Forearm.=--The chief groups of muscles on the forearm -are the _flexors_ and _pronators_ on the anterior surface and the -_extensors_ and _supinators_ on the posterior surface. In general the -flexors and pronators take their origin from on or around the internal -condyle, while the extensors and supinators arise on or around the -external condyle. Where not otherwise stated it will be understood that -such is their origin. In a general way they may by grouped as follows: - - ANTERIOR SURFACE. - { flexor carpi radialis - Flexors of wrist { flexor carpi ulnaris - { palmaris longus - - Flexors of fingers { flexor sublimis digitorum - { flexor profundus digitorum - - Flexor of thumb flexor longus pollicis - - Pronators of hand { pronator radii teres - { pronator quadratus - - POSTERIOR SURFACE. - Extensor of forearm anconeus - - { extensor carpi radialis longior - Extensors of wrist { extensor carpi radialis brevior - { extensor carpi ulnaris - - { extensor ossis metacarpi pollicis - Extensors of thumb { extensor primi internodii pollicis - { extensor secundi internodii pollicis - - Extensor of fingers extensor communis digitorum - - Extensor of index finger extensor indicis - - Extensor of little finger extensor minimi digiti - - Supinators of hand { supinator longus - { supinator brevis - -Of the _flexors of the wrist_ the _flexor carpi radialis_ is inserted -into the base of the index and usually of the third metacarpal bone, -the _flexor carpi ulnaris_ into the fifth metacarpal, the pisiform and -the unciform bones, while the _palmaris longus_ goes to the anterior -annular ligament of the wrist and the palmar fascia of the hand. The -_flexor sublimis digitorum_ is inserted by four tendons into the second -phalanges of the fingers, while the _flexor profundus digitorum_ arises -from the upper part of the ulna and is inserted into the last phalanges -of the fingers. The _flexor of the thumb_ arises from the middle of the -radius and is inserted into the last phalanx of the thumb. Which joint -is flexed by a muscle depends upon the origin and insertion of the -muscle, all those included between being affected. Thus, the _flexor -sublimis digitorum_, which has its origin in part at least from the -condyle and is inserted in the second phalanges of the fingers, flexes -the forearm, wrist, and all the finger-joints but the last, while the -_flexor profundus digitorum_, arising from the ulna, though it flexes -the wrist and fingers, has no power of flexing the forearm. - -The _pronator radii teres_, besides arising from the supra-condylar -ridge, rises from the coronoid process of the ulna. It is inserted into -the middle of the outer surface of the radius and serves to pronate -the forearm. The other pronator, the _pronator quadratus_, is a small -quadrilateral muscle extending transversely across the radius and ulna -just above their carpal extremities. It rises from the anterior surface -of the ulna and is inserted into the anterior external border of the -radius. - -On the back of the forearm the _anconeus_ serves to extend the forearm -only, being inserted into the upper part of the posterior surface of -the ulna. The _extensors of the wrist_ are inserted into the bases of -the various metacarpal bones and have some power to extend the forearm -as well as the wrist. The _extensors of the thumb_, as their names -imply, go one to the metacarpal bone and one to each of the phalanges, -the longest one extending the whole thumb, the others only a part. They -rise from the ulna and radius, not the condyle. The _extensor communis -digitorum_ goes to all the phalanges of all the fingers, the _extensor -minimi digiti_ to those of the little finger only, and the _extensor -indicis_ to those of the index finger, the last two arising short of -the condyle. - -Of the _supinators_ the longer one is inserted into the styloid process -of the radius, while the shorter one, the _supinator brevis_, is -inserted into the upper part of the same bone, both thus serving to -turn the radius on the ulna. - -Where the _tendons_ of the various muscles pass over the wrist, both -front and back, they are covered with a synovial sheath and are held -down by a broad ligament, which some of them perforate, the annular -ligament. The strong fibrous band of the _anterior annular ligament_ -arches over the carpal bones in front. Beneath it pass the median nerve -and the tendons of the flexors of the fingers and thumb. The _posterior -annular ligament_ is of less importance. - -The deep _palmar fascia_ forms a sheath for the muscles of the hand. -In carpenters there sometimes occurs _Dupuytren’s contraction_ of the -palmar fascia, which draws the fingers up. As operation is not always -successful, it is quite a serious matter. - -The _muscles of the hand_ itself include various abductor, adductor, -and short flexor muscles of the thumb and little finger. There also -extend between the metacarpal bones the _lumbricales_, four small -muscles that aid the deep flexor muscles; likewise seven _interossei_, -of which four are dorsal and three palmar. The _dorsal interossei_ -arise by two heads from the adjacent sides of the metacarpal bones and -are inserted into the bases of the first phalanges, thus abducting the -fingers; while the _palmar interossei_, arising from the palmar surface -of the second, fourth, and fifth metacarpals, are inserted into the -three corresponding first phalanges and adduct the fingers toward an -imaginary line drawn through the middle finger. - -=Joints of the Upper Extremity.=--The joints of the upper extremity, -with the exception of the wrist-joint, are the most freely movable of -any in the body, probably because the hand has the finest work to do -and a greater number of motions are required. Even the wrist has much -greater freedom of motion than the corresponding joint in the lower -extremity. - -The _shoulder-joint_ is rather a deep joint, to allow of the varied -motion required, and has a capsular ligament from the margin of the -glenoid fossa above to the neck of the humerus below. The _elbow_, -which is a hinge joint, has an anterior and a posterior ligament and -two lateral ligaments, as is practically the case in all such joints. -The _wrist_ has several ligaments which, taken together, are capsular -in nature. - -=Blood Supply of the Upper Extremity.=--The blood supply of the upper -extremity comes through the _subclavian artery_, which, on the right, -springs from the innominate artery and on the left from the aortic -arch. It remains one trunk as far as the elbow, though different names -have been given to different parts. Thus, as it passes over the lower -border of the first rib, it becomes the _axillary_, and at the lower -border of the axilla, where it starts down the arm, the _brachial_. At -the elbow it divides into the _ulnar_ and _radial arteries_. - -In its upper part the _brachial artery_ lies internal to the humerus -but below it is in front of the bone. The _radial_ runs in a line from -the middle of the elbow anteriorly to the inner side of the styloid -process of the radius and is much exposed to injury in the lower third -of its course, as when the hand is thrust through glass. On it at the -wrist the pulse is counted. It is much smaller than the ulnar and winds -around the outer side of the thumb to the palm, where, with the deep -branch from the ulnar, it forms the _deep palmar arch_. The _ulnar -artery_ passes obliquely inward to the middle of the forearm and thence -along its ulnar border to the palm of the hand, where it divides into -the deep branch and the _superficial palmar arch_ which supplies the -four _digital arteries_. - -From the _axillary artery_ branches go to the chest wall and shoulder, -the most important being the two _circumflex arteries_ to the deltoid. -The brachial has only two branches of any importance, the _superior_ -and _inferior profunda_, both on the upper arm, of course. - -In case of _hemorrhage_ compression can frequently be applied with the -fingers where the subclavian crosses the rib or in the axilla, where -the artery can be pressed up against the humerus. - -=Nerves.=--The nerve supply of the shoulder comes chiefly from the -anterior and posterior _thoracic_, the _suprascapular_, and the -_circumflex_, these last going to the deltoid. The biceps is supplied -by the _musculo-cutaneous_, the triceps by the _musculo-spiral_, and -the brachialis anticus by both. Most of the flexor and pronator muscles -are supplied by the _median_, while the _posterior interosseous_ and -the _musculo-spiral nerves_ go to the extensors and supinators. The -_ulnar nerve_ supplies the hand largely. - - - - -CHAPTER XIII. - -THE LOWER EXTREMITIES. - - -The lower extremities resemble the upper very closely in the -arrangement of the bones, muscles, arteries, and nerves, though -modifications occur, due to the difference in function of the lower -limbs. There is one long bone in the upper part or thigh, the femur, -and two in the lower part or leg, the tibia and fibula, while over the -knee-joint is the patella or knee-cap. The ankle has seven bones and -the foot nineteen like the hand. - -=The Femur.=--The femur is the longest bone in the body, being about -one-fourth the height of the person. It inclines toward its fellow at -the knee in order to bring the knee-joints near the center of gravity -in walking, the amount of inclination varying with the width of the -hips and the height of the person. On account of the greater width of -hip the tendency to knock-knee is greater in women than in men. - -The _shaft_ of the femur is enlarged at the extremities and is -slightly curved forward, the concavity being strengthened at the back -by a longitudinal ridge, the _linea aspera_, along part of which the -gluteus maximus muscle is attached. The _head_, which is covered with -cartilage, except for an oval depression for the attachment of the -ligamentum teres, one of the ligaments of the hip-joint, and which -articulates with the hollow of the acetabulum in the os innominatum, -projects considerably upward, inward, and forward from the shaft, -the _neck_ varying much in length and angle. It is generally more -horizontal in women than in men and in rickets the great weight on -the softened bone tends to press the head down, causing the deformity -known as “_coxa vera_”, in which the neck is almost horizontal. -Extending upward, outward, and backward from the shaft at the base -of the neck, about three-quarters of an inch lower than the head and -about on a level with the acetabulum and the spine of the os pubis, -is the _greater trochanter_. This large, irregular prominence and the -smaller one of the _lesser trochanter_, which is at the lower part of -the base of the neck posteriorly, are for the attachment of muscles -and to assist in rotating the bone. The lower extremity of the femur -is larger than the upper and is flat from before backward. Between its -two large eminences, the external and internal _condyles_, is a smooth -depression in front, the _trochlear surface_, for articulation with the -patella. The external condyle is more prominent in front, the internal -inferiorly, the latter being the longer of the two by about half an -inch. The _epiphysis_ at the lower end of the femur is the only one in -which ossification has begun at birth. Therefore, if ossification is -found there, the child is known to have arrived at full term. - -[Illustration: FIG. 74.--Bones of the lower extremity. (Toldt.)] - -So many large muscles are attached to the femur that the shaft cannot -be detected in the living unless the person is very thin and poorly -developed. The outer surface of the greater trochanter, however, and -the condyles can be felt. - -A string stretched from the anterior superior spine of the ilium to the -tuberosity of the ischium passes in the middle just over the upper edge -of the greater trochanter. The line thus drawn is known as _Nélaton’s -line_ and is of considerable importance in many conditions of the -hip. Thus, if the hip is dislocated, the trochanter will be thrown -above _Nélaton’s line_, and in osteomalacia the pelvis sinks and the -trochanter is again above the line. - -=Thigh Muscles.=--Of the thigh muscles only a few need be mentioned. -One large muscle is the _psoas magnus_, which has its origin on the -front of the last dorsal and all the lumbar vertebræ, passes down -across the brim of the pelvis and under Poupart’s ligament, gradually -diminishing in size, and terminates in a tendon that is inserted into -the lesser trochanter. It serves to flex the thigh on the pelvis and to -rotate it outward. The _psoas parvus_ rises from the last dorsal and -the first lumbar vertebræ and does not go out of the pelvis. - -The _sartorius_ or _tailor muscle_ is flat and ribbon-like and is the -longest muscle in the body. It rises from the anterior superior spine -of the ilium and is inserted into the upper inner surface of the shaft -of the tibia. By it the legs are crossed. It also forms the outer side -of an important landmark, _Scarpa’s triangle_, whose base is formed by -Poupart’s ligament and the inner side by the _adductor magnus muscle_, -which passes from the ramus of the os pubis and the tuberosity of the -ischium to the linea aspera. The _femoral artery_ bisects the triangle -and runs into its apex. - -The bulk of the anterior portion of the thigh is formed by the -_quadriceps extensor_, which is really made up of four muscles, the -_rectus femoris_, whose origin is on the anterior inferior iliac spine -and above the acetabulum; the _vastus externus_, which comes from -the greater trochanter and the upper linea aspera; and the _vastus -internus_ and _crureus_, which rise from the neck of the femur and -the linea aspera. It is inserted into the tubercle of the tibia by -the _ligamentum patellæ_, in which the patella lies. Its action is to -extend the leg. - -At the back and forming the _buttocks_ are the three glutei muscles, -the _gluteus maximus_, _medius_, and _minimus_. All these rise from the -outer side of the ilium and have their insertion on or about the great -trochanter. They serve to hold the trunk erect and to extend, abduct, -and rotate the thigh. - -[Illustration: FIG. 75.] - -[Illustration: FIG. 76.] - -[Illustration: FIG. 77. - -FIG. 75.--Superficial muscles of hip and thigh (from behind): 1, -Gluteus medius; 2, gluteus maximus; 3, vastus externus; 4, biceps -flexor cruris; 5, semitendinosus; 6, semimembranosus; 7, gracilis; 8, -sartorius; 9, adductor magnus; 10, 11, gastrocnemius; 12, origin of -plantaris. (Dorland’s Dictionary.) - -FIG. 76.--Muscles of the inner side of thigh and interior of pelvis: -1, Iliacus; 2, psoas magnus; 3, obturator internus; 4, pyriformis; 5, -erector spinæ; 6, gluteus maximus; 7, sartorius; 8, adductor longus; 9, -gracilis; 10, adductor magnus; 11, semimembranosus; 12, semitendinosus; -13, rectus femoris; 14, vastus internus. (Dorland’s Dictionary.) - -FIG. 77.--Superficial muscles of front of thigh: 1, Insertion of -external oblique into iliac crest; 2, aponeurosis of external oblique; -3, external abdominal ring; 4, gluteus medius; 5, tensor vaginæ -formoris; 6, sartorius; 7, iliopsoas; 8, pectineus; 9, adductor longus; -10, gracilis; 11, adductor magnus; 12, vastus externus; 13, rectus -femoris; 14, vastus internus; 15, biceps flexor cruris. (Dorland’s -Dictionary.)] - -Lower down and forming the back of the thigh are the biceps and the -semitendinosus and semimembranosus muscles. The _biceps_ rises by two -heads from the tuberosity of the ischium and the linea aspera and is -inserted into the head of the fibula. It is on the outer side of the -thigh and its tendon, which embraces the external lateral ligament of -the knee-joint, forms the _outer hamstring_. On the inner side are the -_semitendinosus_ and the _semimembranosus muscles_. These rise from -the tuberosity of the ischium and are inserted, the one into the upper -inner surface of the shaft of the tibia and the other into the internal -tuberosity of the tibia. Their tendons form the _inner hamstring_. -Like the biceps they serve to extend the thigh and flex the leg on the -thigh, but where the biceps rotates the leg out they, being attached to -the inner side of the leg bones, rotate it in. - -=The patella=, or _small pan_, is a flat, somewhat triangular bone -developed in the quadriceps extensor tendon. Four _muscles_ are -attached to it as well as the ligamentum patellæ, which holds it to the -tibia and gives increased leverage by making the quadriceps extensor -work at a greater angle. It articulates with the condyles and serves -to protect the joint. One bursa, the _prepatella bursa_, separates it -from the skin and another, surrounded by adipose tissue, from the head -of the tibia. The external surface can be seen and felt on the front of -the knee and the bone can be moved from side to side when the leg is -straight. - -=Joints of the Lower Extremity.=--The _hip-joint_ is a ball-and-socket -joint but is not so freely movable as the shoulder-joint, the head of -the femur being held in the acetabulum by many strong ligaments, of -which the most important is the _capsular_ ligament. - -The _knee-joint_ is largely a hinge joint, but in some positions it has -some rotation. It is formed by the condyles of the femur, the head of -the tibia, and the patella, and has fourteen ligaments, including the -_ligamentum patellæ_ and the _crucial ligaments_. Its synovial sac is -the largest found in any joint. Two _semilunar cartilages_, placed on -the head of the tibia, serve to deepen the socket for the condyles, -changing somewhat in shape and thickness as the joint moves. The -interval between the thigh and the leg bones can be felt at the knee. -When the leg is extended the juncture of the bones is slightly above -the patella, while in flexion a knife passed below the apex of the -patella will pass into the joint. - -_Congenital dislocation_ of the hip occurs. _Separation of the -epiphysis of the femur_ may occur and sometimes the neck, rarely -the lower part of the shaft, is _fractured_. Either condyle may -be fractured off or there may be a T-fracture, in which case the -popliteal artery may be injured. In _dislocation_ the head may be -behind or in front of the acetabulum. _Impacted hip_, where the neck -of the femur has, in a fall, been driven into the head, is common -in old people. Sometimes, especially in young children, the bone is -infected, _osteomyelitis_. _Sarcoma_ occurs. Most tubercular disease of -the hip originates at the upper extremity of the femur, _tuberculosis_ -generally starting in the head and then attacking the capsule and -the soft parts of the joint. If neglected, shortening of the leg may -result, in which case the bone has to be broken and set at an angle in -order to enable the child to walk. - -[Illustration: FIG. 78.] - -[Illustration: FIG. 79. - -FIG. 78.--Right knee-joint, posterior view. (Leidy.) - -FIG. 79.--Right knee-joint, showing internal ligaments: 2, anterior -crucial ligament; 3, posterior crucial ligament; 4, transverse -ligament; 6, 7, semilunar fibro-cartilages. (Leidy.)] - -Occasionally a bit of cartilage gets broken off in the knee-joint and -wedged between the bones, so that the joint cannot be straightened. -This is _dislocation of the semilunar cartilage_ and necessitates an -operation for removal of the piece. The cartilage will eventually -be replaced by fibrous tissue and in a few months the leg will be -all right. _Dislocation of the knee_ is rare, though it may occur -in any direction. Often the bursæ of the joint are irritated, as by -kneeling to scrub floors, and _bursitis_ or _housemaid’s knee_ results. -_Fracture of the patella_ may be caused by muscular traction or by -direct violence, and is generally repaired by making an incision -and sewing the parts of the bone together. _Tumor albus_ or _white -swelling_ is _tuberculosis of the knee_ and is fairly common in -children. _Specific knee_ means _syphilis of the knee_ and generally -occurs in both knees. - -=The Tibia.=--The tibia or _shin bone_ is next longest to the femur -and is on the inner side of the leg, corresponding to the ulna in the -arm. The _shaft_ is prismoid and is more slender for the lower quarter, -where fracture is consequently most frequent. The anterior border forms -the _crest_ or shin and can be felt for its upper two-thirds. The -lower extremity, which is smaller than the upper, articulates with the -astragalus bone of the ankle and with the fibula. Its _head_ or upper -extremity is expanded into two lateral _tuberositis_ for articulation -with the femur and for muscular attachment, both of which can easily -be felt just below the bend of the knee. Their upper surfaces are -smooth and concave, with a vertical bifid spine in the middle and a -prominent tubercle for the attachment of the semilunar cartilages on -either side. On the anterior surface of the head, below, is a rough -eminence or tubercle, which also can be felt. The lower part of this -is for the attachment of the ligamentum patellæ, while the upper part, -which is smoother, is for the bursa that is placed under the tendon to -prevent friction. On the back of the outer tuberosity is a facet for -the head of the fibula. At the lower end there projects downward on the -inner side, overhanging the arch of the foot, the _internal malleolus_, -the prominent part of the ankle. It is on a higher level and somewhat -farther forward than the _external malleolus_. - -=The Fibula.=--The fibula is the most slender of all the bones in -proportion to its length and is on the outer side of the leg. Its -_head_ is small and placed toward the back of the tibia below the -knee-joint, from which it is excluded. The head articulates with the -external tuberosity and has extending upward from it the styloid -process. To it is attached the _biceps tendon_ or _outer hamstring_. -At the lower extremity of the shaft is the _external malleolus_, which -articulates with the astragalus and forms the outer ankle. The only -parts of the fibula that can be felt, besides the malleolus, which is -very prominent, are the head and the lower external surface of the -shaft. - -In _fracture of the leg_ both bones are usually broken, though either -may be broken separately. _Pott’s fracture_ is fracture of the lower -fibula, and may be caused by stamping hard when stepping on to the -sidewalk. In rickets the tibia becomes bowed outward and forward, -causing _bow leg_, a condition which in very young children may be -rectified by manipulation. Later on braces are needed and after five -years the bones have to be broken and set straight. - -=The Ankle.=--The ankle or _tarsus_ has but seven bones where the -wrist has eight. They are the _os calcis_ or _heel bone_, which is -the largest and strongest and forms the tuberosity of the heel; the -_astragalus_, which is next largest and helps to form the ankle-joint; -the _cuboid_; the _navicular_ (_boat-like_) or _scaphoid_; and the -internal, middle, and external _cuneiform bones_. The astragalus is -above and partially in front of the os calcis, to which is attached -the _tendo Achillis_. The _cuboid_ is on the outer side of the foot, -in front of the os calcis and behind the metatarsals. It is noticeable -in _congenital club-foot_, in which condition the tarsal bones may be -distorted in shape and misplaced. The _navicular_ or _scaphoid_ is -on the inner side of the foot, between the astragalus and the three -cuneiform bones. - -=The Foot.=--There are five _metatarsal bones_ in the foot, -corresponding to the five metacarpals in the hand, and the toes have -the same number of _phalanges_ as the fingers, though they are shorter -and stronger. The big toe corresponds to the thumb. - -[Illustration: FIG. 80.--Bones of the right foot, dorsal surface: -1, Astragalus; 2, talus; 3, os calcis, 4, navicular; 5, internal -cuneiform; 6, middle cuneiform; 7, external cuneiform; 8, cuboid; 9, -metatarsus; 10-14, phalanges. (Leidy.)] - -_Fracture_ of the os calcis and the astragalus are most commonly caused -by a fall from a height, while the metatarsals and phalanges are -generally broken by something heavy falling upon them. Because of their -delicate structure, their distance from the heart, and the differences -of temperature to which they are subjected, the tarsal bones are -especially liable to become _tubercular_, amputation of the feet even -becoming necessary at times. In diabetes there may be a perforating -ulcer on the sole of the foot and the bone may become diseased. - -[Illustration: FIG. 81.] - -[Illustration: FIG. 82.] - -[Illustration: FIG. 83. - -FIG. 81.--Superficial muscles of the leg from inner side: 1, -Vastus internus; 2, sartorius; 3, gracilis; 4, semitendinosus; 5, -semimembranosus; 6, inner head of gastrocnemius; 7, soleus; 8, tendon -of plantaris; 9, tendon of tibialis posticus; 10, flexor longus -digitorum; 11, flexor longus hallucis; 12, tibialis anticus; 13, -abductor hallucis. (Dorland’s Dictionary.) - -FIG. 82.--Muscles of leg and foot (from before): 1, Tendon of rectus -femoris; 2, vastus internus; 3, vastus externus; 4, sartorius; 5, -iliotibial band; 6, inner head of gastrocnemius; 7, inner part of -soleus; 8, tibialis anticus; 9, extensor proprius hallucis; 10, -extensor longus digitorum; 11, peroneus longus; 12, peroneus brevis; -13, peroneus tertius; 14, origin of extensor brevis digitorum. -(Dorland’s Dictionary.) - -FIG. 83.--Superficial muscles of leg (from behind): 1, Vastus externus; -2, biceps flexor cruris; 3, semitendinosus; 4, semimembranosus; 5, -gracilis; 6, sartorius; 7, outer, and 8, inner, head of gastrocnemius; -9, plantaris; 10, soleus; 11, peroneus longus; 12, peroneus brevis; 13, -flexor longus digitorum; 14, tibialis posticus; 15, lower fibers of -flexor longus hallucis. (Dorland’s Dictionary.)] - -=Muscles of the Leg.=--The greater part of the calf of the leg is -formed by the _gastrocnemius_, a large bulging muscle, which rises from -the condyles of the femur and is inserted along with the _soleus_, -whose origin is on the back of the upper fibula, and the _plantaris_, -which comes from the linea aspera, into the os calcis by a common -tendon, the _tendo Achillis_, the largest and strongest tendon in -the body. Its action is to extend the foot and to rotate it slightly -inward. Other extensors of the foot, which also evert it, are the -_peroneus longus_ and the _peroneus brevis_ at the upper and outer part -of the leg, the former rising from the outer tuberosity of the tibia -and the upper fibula and being inserted into the first metatarsal and -the internal cuneiform, the latter arising from the lower fibula and -being inserted into the fifth metatarsal. The foot is flexed, adducted, -and rotated inward by means of the _tibialis anticus_, which rises from -the outer tuberosity and the upper two-thirds of the outer surface of -the tibia and is inserted into the internal cuneiform bone. - -In the foot, and corresponding to the palmar fascia in the hand, is -the _plantar fascia_, the densest of all fibrous membranes. There are -also various annular ligaments, and the _foot muscles_ are arranged -similarly to those in the hand. - -=The Blood Supply of the Lower Extremity.=--The blood supply of the -lower extremity comes from the _external iliac artery_, a branch of the -_common iliac_, which passes obliquely downward and outward along the -border of the psoas muscle to Poupart’s ligament, where it enters the -thigh and becomes the _femoral artery_. Its only important branches are -the _deep epigastric_, which goes up along the internal abdominal ring, -and the _deep circumflex iliac_. As the _femoral artery_ it passes -down the inner side of the thigh to the internal condyle of the femur, -being very superficial at Scarpa’s triangle, where it can be compressed -with the thumb to stop hemorrhage below. If a tourniquet is applied, -it should be applied a little lower down. The first and most important -branch of the femoral is the _profunda femoris_. - -About two-thirds of the way to the knee the artery takes the name -_popliteal_. It lies superficially in the popliteal space back of the -knee, but above and below it is covered with muscles. Its branches -supply the knee-joint and nearby muscles and are unimportant. At the -lower border of the _popliteus muscle_, a small muscle at the knee, it -divides into the _anterior and posterior tibial arteries_. The course -of the former of these may be marked by a line from the inner side of -the head of the fibula to midway between the malleoli at the front of -the ankle, where it terminates in the _dorsalis pedis artery_ for the -back of the foot. By this last the pulse is sometimes taken and its -pulsation is a guide in determining how high up to amputate in gangrene -of the foot. The posterior tibial extends obliquely down the back of -the leg to the heel, where it divides into the _internal and external -plantar arteries_ which go to the sole of the foot. Its most important -branch is the _peroneal_. - -Besides the _deep veins_ accompanying the arteries there are the -_superficial veins_, the _internal_ or _long saphenous_ on the inner -side of the leg and thigh and the _external_ or _short saphenous_ on -the middle of the leg posteriorly and emptying into the popliteal vein. -Varicosity often occurs in these veins. - -=Nerves.=--The nerves of the muscles about the hip are branches of the -_lumbar nerve_. The _anterior crural_ supplies the anterior part of -the thigh, the _gluteal_ the muscles of the same name, and the _great -sciatic_ the large muscles of the back of the thigh. Below the knee -the _anterior tibial_ goes to the tibialis anticus and the _internal -popliteal_ to the muscles of the calf, while the peroneus muscles are -supplied by the _musculo-cutaneous_. - - - - -INDEX. - - - Abdomen, 132 - muscles, 132, _et seq._ - nerves, 134 - regions, 134, 135 - contents, 135, 136 - Abdominal aorta, 107, 109 - Abducens nerve, 83 - Abscess, 34, 51, 52, 100, 137, 152, 159, 168 - Absorbent vessels or lymphatics, 34 - Absorption of food, 33 - in intestines, 144 - in mouth, 136 - in stomach, 140 - Accommodation of eye, 72 - Acetabulum, 162, 187 - Acromion process, 173 - Adam’s apple, 121 - Adductor magnus muscle, 190 - Adenoids, 62 - Adipose tissue, 16 - Air, changes by breathing, 129, 130 - complemental, 129 - residual, 129 - supplemental, 129 - tidal, 129 - Air cells, 27 - Albumin in urine, 158 - Albuminoids, 12 - Alimentary canal, 136, _et seq._ - Alveoli of lungs, 126 - Amœba, 12 - Ampullæ of mamma or breast, 100 - Amputation, 177 - Amylopsin, 144 - Anabolism, 147 - Anasarca, 152 - Anatomy, 11 - Anconeus muscle, 182, 183 - Anemia, 120 - Aneurism, 109 - Ankle, 195 - Annular ligaments, 184, 198 - Ano-spinal reflex, 146 - Antrum of Highmore, 54, 57 - Anus, 141, 146 - Aorta, 99, 107, 109 - Aortic valve, 104 - Aponeuroses, 23 - Apoplexy, 79, 118 - Appendages of the skin, 40 - Appendix, vermiform, 145 - Aqueous humor, 70 - Arachnoid, 76 - Areola, 100 - Areolar tissue, 15 - Arteries, 27, 28, 29, 107 - nerves, 29 - of back, 94, 95 - of brain, 77 - of breast, 100 - of chest, 99 - of heart, 107 - of intestine, 143, 145 - of kidney, 156 - of lower extremity, 198, 199 - of organs of generation, 168 - of pancreas, 153 - of spleen, 153 - of stomach, 139 - of upper extremity, 185, 186 - structure, 27 - Artery, axillary, 99, 100, 108, 185 - basilar, 77, 108 - brachial, 108, 177, 185 - carotid, common, 107, 108 - internal and external, 108, 137 - celiac axis, 109, 143, 150, 153 - cerebral, 77 - circumflex, 186 - coronary, 107 - communicating, 78 - digital, 186 - dorsalis pedis, 199 - epigastric, deep, 198 - facial, 28 - femoral, 190, 198 - gastric, 109 - hepatic, 109, 150 - iliac, common, 107, 109 - internal and external, 95, 109, 198 - circumflex, 198 - innominate, 107 - intercostal, 95, 97, 100, 108 - lumbar, 95, 109 - mammary, internal, 99, 100, 108 - mediastinal, 99 - mesenteric, 109, 143, 145, 153 - ophthalmic, 70 - peroneal, 199 - phrenic, 99, 109 - plantar, internal and external, 199 - popliteal, 198 - profunda, superior and inferior, 175, 186 - femoris, 198 - pudic, 168 - pulmonary, 106, 110 - radial, 108, 185 - renal, 109 - spermatic or ovarian, 109, 168 - splenic, 109, 153 - subclavian, 94, 99, 107, 108, 185 - suprarenal, 109 - suprascapular, 94 - thyroid axis, 108 - tibial, 198 - transversalis colli, 94 - ulnar, 108, 185 - umbilical, 107 - uterine, 168 - vertebral, 77 - Arytenoid cartilages, 122 - Ascending aorta, 107 - colon, 145 - Ascites, 34, 152 - Asphyxia, 128 - Astigmatism, 73 - Astragalus, 195 - Atlas, 91 - Auditory meatus, 52 - canal, external, 63 - internal, 64 - center, 81 - nerve, 64, 65, 84 - Auricles of heart, 103 - Axilla, 32 - Axillary artery, 99, 100, 108, 185 - Axis, 91 - Axis-cylinder process, 36, 37 - - Back, 88, _et seq._ - muscles, 93, 94 - arteries, 94, 95 - nerves, 95 - Basilar artery, 77, 108 - Basilic vein, 109 - Biceps of arm, 175, 176 - of leg, 190, 191 - Bicipital groove, 175 - Bicuspid or mitral valve, 104 - teeth, 60 - Bile, 36, 143, 150 - Bilirubin, 12, 143, 151 - Biliverdin, 143, 151 - Bladder, 160 - Blind spot, 70 - Blood, 27, 116, _et seq._ - amount, 116 - arterial and venous, 29 - circulation of, 29, 105, _et seq._ - coagulation, 117, 118 - coloring matter, 119 - composition, 116, 117 - corpuscles, 116, 118, _et seq._ - fibrin, 117 - functions of, 116 - plaques, 120 - plasma, 33, 116, 117 - pressure, 114, 115 - serum, 117 - vessels, 27, _et seq._ - Bone, 17 - astragalus, 195 - atlas, 91 - axis, 91 - canaliculi, 17 - cancellous or spongy, 17 - carpal, 180, 181 - chemical composition, 18 - clavicle, 171 - coccyx, 90, 161 - compact, 17, 18 - cuboid, 195 - cuneiform, 181, 195 - endosteum of, 18 - ethmoid, 48, 53 - femur, 187 - fibula, 194, 195 - formation of, 18 - frontal, 49 - Haversian canals of, 17 - humerus, 175 - hyoid, 60 - ilium, 161, 162 - incus, 63 - innominate, 161, 162 - ischium, 161, 163 - lachrymal, 48, 54 - lacunæ of, 17 - lamellæ of, 17 - malar, 48, 54 - malleus, 63 - marrow of, 18 - maxillary, inferior, 48, 55 - superior, 48, 54 - metacarpal, 181 - metatarsal, 195 - nasal, 48, 55 - navicular, 195 - occipital, 48, 50 - os calcis, 195 - os innominatum, 161, 162 - os magnum, 181 - palate, 48, 54 - parietal, 48, 49 - patella, 19, 192 - pelvis, 161 - periosteum of, 18 - phalanges, of foot, 195 - of hand, 181 - pisiform, 181 - pubes, 161, 163 - radius, 178, 179 - ribs, 97, 98 - sacrum, 90, 161 - scaphoid, 181, 195 - scapula, 173 - semilunar, 181 - sphenoid, 48, 52 - stapes, 63 - sternum, 97 - structure of, 17 - tarsal, 195 - temporal, 48, 51 - tibia, 194 - trapezium, 181 - trapezoid, 181 - turbinated, 53 - inferior, 48, 53, 54 - ulna, 177, 178 - unciform, 181 - vertebræ, 88 - vomer, 48, 55 - Bones, classification of, 19 - flat, 20 - function of, 19, 20 - long, 19 - of back, 88 - of chest, 97, 98 - of cranium, 48, _et seq._ - of face, 53, _et seq._ - of lower extremity, 187, _et seq._ - of upper extremity, 171, _et seq._ - pelvic, 161, _et seq._ - sesamoid, 19 - short, 20 - Wormian, 19, 49 - Bow leg, 195 - Brachial artery, 108, 177, 185 - plexus, 84, 85 - Brachialis anticus, 175, 177 - Brain, 75, _et seq._ - areas, 81, 82 - arteries, 77 - function, 80, _et seq._ - parts, 75 - Broad ligaments of uterus, 165, 166, 168 - Bronchi, 123, 125 - Buffy coat, 117 - Bursæ, synovial, 20, 178 - Bursitis, 194 - Buttocks, 190 - - Canal, alimentary, 136, _et seq._ - auditory, 63, 64 - central, of cord, 81 - Haversian, 17 - semicircular, 64, 66 - Canaliculi of bone, 17 - Cancellous tissue of bone, 17 - Cancer, 35, 58, 62, 100, 122, 139, 146, 169 - Canine teeth, 60 - Canthus of eye, 67, 68 - Capillaries, 28, 29 - Capitellum, 175 - Capsular ligament of hip, 193 - Carbohydrates, 12, 26, 147, 148, 151 - Cardiac cycle, 104 - muscle, 22, 25 - nerve, 78 - plexus, 87 - Caries, 98 - Carotids, common, 107, 108 - internal and external, 108, 137 - Carpal bones, 180, 181 - Carpus or wrist, 180, 181 - Cartilage, 16 - Cartilages, arytenoid, 122 - costal, 98 - cricoid, 121 - thyroid, 121 - triangular, 57 - Casein, 11 - Cauda equina, 79, 91 - Cecum, 145 - Celiac axis, 109, 150, 153 - Cells, 12, 13 - Central canal of cord, 81 - Cephalocele, 53 - Cerebellum, 51, 78 - Cerebral arteries, 77 - veins, 78 - Cerebro-spinal fluid, 34, 76, 79 - meningitis, 79 - nervous system, 75, _et seq._ - Cerebrum or brain proper, 51, 75 - Cervical nerves, 84 - plexus, 84 - vertebræ, 90, 91 - Cervix of uterus, 168 - Chemical composition of the body, 11 - of bone, 18 - Chest or thorax, 96 - arteries, 99 - bones, 97, 98 - muscles, 98, 99 - nerves, 99 - Cholesterin, 143 - Chordæ tendineæ, 104 - Choroid, 68 - Chromatic aberration, 73 - Chyle, 32, 33, 144 - Chyme, 139, 140 - Cilia, 15, 27 - Ciliary muscles, 69, 72 - processes, 69, 72 - Circle of Willis, 78, 108 - Circulation of the blood, fetal, 106, 107 - portal, 109, 110 - pulmonary, 110 - systemic, 105, 106, 107, _et seq._, 112, 113 - Circumflex artery, 186 - Circumflex nerve, 85, 186 - Circumvallate papillæ, 61 - Cirrhosis of liver, 152 - Clavicle, 171 - Cleft palate, 55 - Clitoris, 170 - Clotting of blood, 23, 117, 118 - of lymph, 33 - of muscle, 23 - Club-foot, 195 - Coccygeal nerve, 84 - vertebræ, 90 - Coccyx, 90, 161 - Cochlea, 64, 65 - Colles’ fracture, 171, 180 - Color blindness, 73 - perception, 73 - Coloring matters, 12 - of bile, 143, 151 - of blood, 119 - Colon, ascending, 145 - descending, 145 - transverse, 145 - Columnæ carneæ, 104 - Commissures of cord, 80 - Common bile duct, 150 - Communicating arteries, 78 - Compact tissue of bone, 17, 18 - Condyles, humerus, 175 - femur, 189 - Conjunctiva, 67 - Conjugate focus, 71 - Convolutions of brain, 76 - Connective tissue, 15, _et seq._ - areolar, 15 - bony, 17 - cartilaginous, 16 - elastic, 15 - fatty or adipose, 16 - fibrous, 15 - Coraco-brachialis, 177 - Coracoid process of scapula, 173 - Cordiform tendon, 98 - Cornea, 27, 68, 70 - Cornicula laryngis, 122 - Coronary artery, 107 - sinus, 105 - valve, 105 - Coronal suture, 48 - Coronoid fossa, 175 - process, 178 - Corpus luteum, 166 - Corpuscles of blood, 116, 118, _et seq._ - tactile, 37, 39, 46 - Corti, organ of, 65 - Costal cartilages, 98 - Coughing, 131 - “Coxa vera,” 189 - Cranial nerves, 77, 78, 83, 84 - Craniotabes, 53 - Cranium, bones of, 48, _et seq._ - Cribriform plate of ethmoid bone, 53 - Cricoid cartilage, 121 - Crista galli, 53 - Cross eye, 72 - Crossed pyramidal tract, 82 - Crucial ligaments, 193 - Crural nerves, 85, 199 - Crureus, 190 - Crying, 131 - Crypts of Lieberkühn, 143, 144, 145 - Crystalline lens, 69, 70 - Cuboid bone, 195 - Cuneiform bones, ankle, 195 - wrist, 181 - cartilages, 122 - Cutaneous nerves, 46, 85 - Cystic duct, 143, 152 - - Deltoid, 174 - Dendrites, 36 - Derma, 39 - Descending aorta, 107 - colon, 145 - Diabetes mellitus, 151, 196 - Diaphragm, 98, 99, 128 - Diaphysis, 18 - Diastole, 104, 106 - Differentiation of tissues, 13 - Digestion, in mouth, 136 - in small intestine, 143, 144 - in stomach, 139, 140 - of fats, 144 - of proteids, 140, 144 - of starch, 136, 144 - Digital arteries, 186 - Diphtheria, 35 - Diploë, 20, 48 - Direct cerebellar tract, 82 - pyramidal tract, 80, 82 - Dislocation, 180, 193, 194 - Diuretics, 158 - Dorsal or thoracic nerves, 84, 85 - vertebræ, 90, 91 - Dorsalis pedis artery, 199 - Duct, common bile, 150 - cystic, 143, 152 - ejaculatory, 165 - hepatic, 143, 150 - lachrymal, 68 - of Rivinus, 62 - pancreatic, 153 - right lymphatic, 31, 32 - Stensen’s, 62 - Wharton’s, 62 - Ductless glands, 36 - Ductus arteriosus, 106, 107 - communis choledochus or common bile duct, 150 - Duodenum, 142 - Dupuytren’s contraction, 184 - Dura mater, 15, 76, 79 - Ear, 63, _et seq._ - external, 63 - function of, 65 - internal, 64 - function of, 65 - middle, 63 - function of, 65 - Edema, 33, 34, 122 - Eighth nerve, 64, 84 - Ejaculatory duct, 165 - Elbow, 32 - joint, 185 - Elastic tissue, 15 - Eleventh nerve, 84 - Emmetropic eye, 72 - Emphysema, 97 - Empyema of gall-bladder, 152, 153 - of lungs, 126 - End bulbs, 37 - Endocardium, 103 - Endolymph, 64, 65 - Endosteum, 18 - Endothelium, 14, 40 - Ensiform cartilage, 97 - Epidermis, 27, 39 - Epigastric artery, 198 - Epigastrium, 135 - Epiglottis, 60, 121, 136 - Epiphysis, 18, 189, 193 - Epithelium, 14, 27 - ciliated, 15, 27 - columnar, 14 - glandular, 14 - pavement, 14 - simple, 14 - stratified, 14 - Erythrocytes, 118, 119 - Esophagus, 138 - Ethmoid bone, 53 - Eustachian tubes, 52, 63 - valve, 106, 107 - Excreting glands, 35 - Extensor carpi radialis longior, 182, 183 - brevior, 182, 183 - ulnaris, 182, 183 - communis digitorum, 182, 184 - indicis, 182, 184 - minimi digiti, 182, 184 - ossis metacarpi pollicis, 182, 183 - primi internodii pollicis, 182, 183 - secundi internodii pollicis, 182, 183 - Eye, 66, _et seq._ - accommodation, 72 - coats of, 68 - color of, 69 - formation of image in, 70, _et seq._ - humors of, 70 - muscles of, 67 - nerves of, 67, 68 - teeth, 60 - Eyeball, 66 - Eyebrows, 66 - Eyelashes, 67 - Eyelids, 66, 67 - - Face, bones of, 53, _et seq._ - Facial artery, 28 - nerve, 83, 84 - Fallopian tubes, 166, 167 - Far-sightedness, 72, 73 - Fat or adipose tissue, 16 - Fats, 12, 147, 148 - absorption, 144 - digestion, 143, 144 - False pelvis, 163 - ribs, 97 - Fascia, lumbar, 133 - Fascia, palmar, 184 - plantar, 198 - Fasciæ, 15, 21 - Fasciculi, 21 - Fauces, pillars of, 59 - Feces, 146 - Female generative organs, 163, 165, _et seq._ - Femoral artery, 190, 198 - Femur, 187 - Fenestra ovalis, 63, 65 - rotunda, 65 - Ferments, 12, 136, 144 - Fetal circulation, 106, 107 - Fetus, 111 - Fever, 45 - Fibrin, 11, 23, 33, 117 - ferment, 117 - Fibrinogen, 117 - Fibrous tissue, 15 - Fibula, 194, 195 - Fifth nerve, 83 - Filum terminale, 78, 91 - Fimbriæ, 167 - First nerve, 83 - Fissure of Rolando, 75, 82 - of Sylvius, 75 - Flexor carpi radialis, 182, 183 - ulnaris, 182, 183 - longus pollicis, 182, 183 - profundus digitorum, 182, 183 - sublimis digitorum, 182, 183 - Floating ribs, 97 - Follicles, Graafian, 166 - Fontanelles, 19, 49 - Food, 147 - amount, 148 - classes of, 147 - cooking, 148 - function, 147, 148 - Foot, bones of, 195, 196 - muscles of, 198 - Foramen, intervertebral, 90 - magnum, 50 - nutrient, 19 - obturator, 163 - of Majendie, 79 - optic, 66, 70 - ovale, 106 - Foreign bodies, 118, 122, 137, 146 - Fossa, coronoid, 175 - glenoid, 51 - iliac, 163 - nasal, 55, 57 - olecranon, 175 - Fourchette, 170 - Fourth nerve, 68, 83 - Fovea centralis, 70 - Fractures, 98, 164, 171, 174, 175, 177, 180, 181, 193, 194, 195, 196 - Frenum of tongue, 60 - Frontal bone, 48, 49 - - Gall-bladder 143, 152, 153 - stones, 143 - Ganglia, 87, 110 - Gangrene, 180, 199 - Gastric artery, 109 - glands, 35 - juice, 139 - vein, 110, 150 - Gastrocnemius, 196 - Generative organs, female, 163, 165, _et seq._ - male, 163, 164, 165 - Genito-crural nerve, 85 - Gladiolus 97 - Glands, 32, 35, 36 - ductless, 36 - excreting, 35 - functions, 36 - gastric, 35 - lachrymal, 68 - lymphatic, 32, 34, 35 - mammary, 99, 100 - Meibomian, 67 - of Lieberkühn, 143, 144, 145 - parotid, 51, 62 - Peyer’s, 142 - procreating, 165 - prostate, 164, 165 - racemose, 35 - salivary, 35, 61, 136 - sebaceous, 35, 40, 41 - secreting, 35 - solitary, 142, 145 - sublingual, 56, 62 - submaxillary, 56, 62 - sweat, 35, 42 - thymus, 124 - thyroid, 124 - Glenoid cavity, 173 - fossa, 51 - Globulin, 11 - Glosso-pharyngeal nerve, 61, 84 - Glottis, 122, 129 - Gluteal nerves, 199 - Glutei muscles, 190 - Glycogen, 26, 36, 150, 151 - Goiter, 124 - Gonorrhea, 160, 168 - Graafian follicles, 166 - Gray matter of brain and cord, 36, 75, 76, 78, 80, 81 - Green-stick fracture, 19 - Groin, glands of, 32, 35 - Gustatory cells, 61 - - Hair, 27, 40 - follicle, 40 - Hamstring, inner, 191 - outer, 191 - Hard palate, 55, 59 - Haversian canals, 17 - Hearing, sense of, 65 - Heart, 101, _et seq._ - beat, 102, 104, 111, 112 - nerves, 110, 111 - position, 102 - sounds, 111 - structure, 103, 104 - Heat center, 45 - production, 44 - prostration, 45 - stroke, 45 - Hemoglobin, 119, 130 - Hemorrhage, 139, 186 - Hemorrhoidal veins, 146 - Hemorrhoids, 146 - Henle’s loops, 156 - Hepatic artery, 109, 150 - duct, 143, 150 - flexure, 145, 146 - veins, 110 - Hernia, 146, 164 - Hiccough, 99, 131 - Highmore, antrum of, 54, 57 - Hilum of kidney, 155 - Hip-joint, 192 - Housemaid’s knee, 194 - Humerus, 175 - Humors of eye, 70 - Humpback or Pott’s disease, 91 - Hydrocarbons, 12 - Hydrocephalus, 34 - Hydrochloric acid, 139, 140 - Hydrothorax, 34 - Hymen, 170 - Hyoid bone, 60 - Hypermetropia or far-sightedness, 72, 73 - Hypochondriac regions, 135 - Hypogastric plexus, 87 - region, 135 - Hypoglossal nerve, 84 - - Idiocy, 53 - Ileo-cecal valve, 142, 145 - Ileo-pectineal line, 163 - Ileum, 142 - Iliac artery, common, 107, 109 - deep circumflex, 198 - external and internal, 95, 109, 198 - fosssæ, 163 - Ilio-hypogastric nerve, 85 - Ilio-inguinal nerve, 85 - Ilium, 161, 162 - Impacted hip, 193 - Incisor teeth, 60 - Incus, 63 - Infundibula of lung, 125, 127 - Inguinal regions, 135 - Innominate artery, 107 - bone, 161, 162 - veins, 109 - Inorganic compounds in body, 12 - Intercostal arteries, 95, 97, 100, 108 - muscles, 98, 128 - nerves, 85, 97, 99, 134 - Intercellular substance, 14, 17 - Interossei muscles, 184 - Interosseous nerves, 85, 186 - Internal secretion, 36 - Intervertebral foramen, 90 - Intestines, 141, _et seq._ - large, 141, 145 - function, 146 - glands, 145 - nerves, 145 - structure, 145, 146 - small, 141, 142, _et seq._ - blood-vessels, 143 - function, 143, 144 - glands, 142, 143 - nerves, 143 - structure, 142 - Intima, 27 - Intralobular vein, 150 - Intussusception, 146 - Involuntary muscle, 21 - Iris, 68, 69, 72 - Ischium, 161, 163 - Island of Reil, 75 - - Jaundice, 35, 152, 153, 158 - Jejunum, 142 - Joints, 15, 20 - classes of, 20, 21 - ankle, 195 - elbow, 21, 185 - hip, 21, 192 - knee, 193 - motion of, 20, 21 - shoulder, 21, 185 - wrist, 185 - Jugular veins, 109 - Juice, gastric, 139 - pancreatic, 143, 144, 153 - - Katabolism, 147 - Kidneys, 155, _et seq._ - floating, 159 - function, 156, _et seq._ - position, 155 - structure, 155, 156 - Knee-jerk, 83 - Knee-joint, 193 - - Labia majora, 169 - minora or nymphæ, 170 - Labyrinth, membranous, 64, 65 - osseous, 64 - Lachrymal bones, 48, 54 - canal, 54, 57 - duct, 68 - gland, 68 - sac, 54, 68 - Lacteals, 32, 144 - Lacunæ of bone, 17 - Lambdoidal suture, 48 - Lamellæ of bone, 17 - Laminæ of vertebræ, 89 - Large intestine, 141, 145 - Laryngitis, 122 - Laryngotomy, 122 - Larynx, 121 - Latissimus dorsi, 93 - Laughing, 131 - Lens, crystalline, 69, 70 - Leucocytes, 33, 34, 119, 120 - Levator scapulæ, 93 - Levatores of ribs, 129 - Lieberkühn, glands of, 143, 144, 145 - Ligaments, 15, 20, 21 - annular, 184, 198 - broad, of uterus, 165, 166, 168 - capsular, of hip, 21, 193 - crucial, of knee, 193 - orbicular, 178 - Poupart’s, 132 - round, of uterus, 168 - suspensory, of liver, 149 - thyro-arytenoid, 122 - Ligamentum nuchæ, 50, 91, 93 - patellæ, 190, 192, 193, 194 - teres, 187 - Line, Nélaton’s, 189 - Linea alba, 132 - aspera, 187 - Liver, 36, 149, _et seq._ - blood supply, 150 - diseases of, 152 - function, 150, _et seq._ - position, 149 - structure, 149, 150 - Loops of Henle, 156 - Lower extremities, 187, _et seq._ - Lumbar artery, 95, 109 - fascia, 133 - nerves, 84, 85 - plexus, 84 - regions, 135 - vertebræ, 90 - Lumbricales, 184 - Lungs, 125, _et seq._ - function, 127, _et seq._ - nerves, 127 - position, 126 - structure, 126, 127 - Lupus, 58 - Lymph, 30, 32 - capillaries, 30 - character, 32, 33 - flow of, 33 - function, 34 - spaces, 30 - transudation of, 33 - Lymphatic glands, 32, 34, 35 - system, 27, 29, _et seq._ - vessels, 30, 31 - valves of, 31, 32, 33 - - Macula lutea, 70 - Malar or cheek bone, 48, 54 - Malaria, 154 - Male organs of generation, 163, 164, 165 - Malleolus of fibula, 194, 195 - of tibia, 194 - Malleus, 63 - Malpighian bodies, 156 - pyramids, 156 - Mammary artery, internal, 99, 100, 108 - glands, 99, 100 - Manubrium, 97 - Marrow of bone, 18 - Masseter, 51, 54 - Mastoid abscess, 51, 52 - cells, 51, 64 - portion of temporal bone, 51 - Maxillary bone, inferior, 48, 55 - superior, 48, 54 - McBurney’s point, 145 - Meatus, auditory, 52, 65 - nasal, 57 - urinarius, 160, 165, 170 - Median, cephalic vein, 109 - nerve, 85, 186 - vein, 109 - Mediastinal artery, 99 - Mediastinum, 32, 126 - Medulla or marrow, 18 - Medulla oblongata, 78, 79, 82 - Medullary artery, 19 - canal, 19 - sheath, 37 - Meibomian duct, 74 - glands, 67 - Membrana tympani or drum, 63 - Membranous labyrinth, 64, 65 - Mesenteric arteries, 109, 143, 145, 153 - veins, 110, 150 - Mesenteries, 32, 134 - Metabolism, 45, 147, 151, 152 - Metacarpal bones, 181 - Metatarsal bones, 195 - Micturition, 157 - Milk teeth, 60 - Mitral valve, 104 - Molar teeth, 60 - Monometer, 114 - Mons Veneris, 169 - Motor areas, 81, 82 - center, 81, 82 - oculi nerve, 68, 83 - tract, 82 - Mouth, 59, _et seq._ - Mucous membrane, 40 - Mucus, 40 - Mumps, 62 - Muscle, 21, _et seq._ - action, 23, 24 - cardiac, 22, 25 - characteristics, 22, 23, 24, 25 - classes of, 21 - fatigue of, 26, 27 - function of, 24 - smooth, 21, 25 - sounds, 25 - striated, 21, 23, 25 - work, 25, 26 - Muscles of abdomen, 132, _et seq._ - of arm, 175, 176, 177 - of back, 93, 94 - of chest, 98, 99, 128 - of foot, 198 - of forearm, 182 - of hand, 184 - of head, 50, 51, 54, 55, 58, 67, 69 - of leg, 196, _et seq._ - of neck, 51, 92, 93, 129 - of shoulder, 174 - of thigh, 189, _et seq._ - Musculo-cutaneous nerve, 85, 186, 199 - Musculo-spiral nerve, 85, 175, 186 - Musical sounds, 65 - Myopia or near-sightedness, 72, 73 - Myosin, 11, 23 - Myosinogen, 23 - - Nails, 27, 40 - Nares, 57 - Nasal bones, 55 - duct, 68 - fossæ, 55, 57 - meatus, 57 - Nasal septum, 55 - Navicular or scaphoid bone, 195 - Near-sightedness, 72, 73 - Neck, glands of, 32 - muscles of, 51, 92 - Nélaton’s line, 189 - Nerve, 37 - action of, 37, 38, 83 - cell or gray matter, 36 - fiber or white matter, 36 - function, 37 - ganglia, 87, 110 - motor, 82 - plexus, 29, 84, _et seq._ - sensory, 82, 83 - terminations, 37 - Nerves, 24, 36 - abducens, 83 - auditory, 64, 65, 84 - cardiac, 78 - cervical, 84 - circumflex, 85, 186 - coccygeal, 84 - cranial, 77, 78, 83, 84 - crural, anterior, 85, 199 - cutaneous, 46, 85 - dorsal or thoracic, 84, 85 - eighth, 64, 84 - eleventh, 84 - facial, 83 - fifth, 83 - first, 83 - fourth, 68, 83 - genito-crural, 85 - glosso-pharyngeal, 61, 84 - gluteal, 199 - hypoglossal, 84 - ilio-hypogastric, 61, 85 - ilio-inguinal, 85 - intercostal, 85, 97, 99, 134 - interosseous, 85, 186 - lumbar, 84, 85 - median, 85, 186 - motor oculi, 68, 83 - musculo-cutaneous, 85, 186, 199 - musculo-spiral, 85, 175, 186 - ninth, 84 - obturator, 85 - olfactory, 53, 58, 83 - optic, 70, 71, 76, 83 - patheticus, 83 - phrenic, 85, 99, 130 - plantar, 85 - pneumogastric, 84, 110, 111, 127, 130, 153 - popliteal, 85, 199 - post-tibial, 85 - radial, 85 - sacral, 84 - sciatic, 85, 163, 199 - second, 70, 83 - seventh, 83 - sixth, 68, 83 - spinal, 84, 95 - accessory, 84, 95, 137 - suprascapular, 186 - sympathetic, 87, 110, 127, 137, 143, 145, 168 - tenth, 84 - third, 68, 72, 83 - thoracic, 186 - cutaneous, 100 - tibial, 86, 87, 199 - trifacial, 61, 83 - twelfth, 84 - ulnar, 85, 175, 186 - vagus, 84, 110, 111, 127, 130, 153 - vasoconstrictors, 115 - dilators, 115 - motor, 29, 78, 115 - Nervous system, 38, 75, _et seq._ - tissue, 13, 36 - Neurilemma, 37 - Ninth nerve, 84 - Nipple, 100 - Nose, 57, 58 - bleed, 59 - Nucleolus, 12 - Nucleus, 12 - Nutrient foramen, 19 - Nymphæ, 170 - - Oblique muscles of abdomen, 132 - of eye, 68 - Obturator foramen, 163 - nerve, 85 - Occipital bone, 48, 50 - Occipito-frontalis muscle, 51 - Odontoid process of axis, 91 - Olecranon fossa, 175 - process, 178 - Olfactory bulbs, 53, 58, 76 - cells, 58 - grooves, 53 - nerves, 53, 58, 83 - tract, 58, 76 - Omenta, 134, 146 - Ophthalmic artery, 70 - Optic axis, 70 - commissure, 76 - foramen, 66, 70 - nerve, 70, 71, 76, 83 - tract, 76 - Orbicular ligament, 178 - Orbicularis palpebrarum, 67 - Orbit of eye, 54, 66 - Organ of Corti, 65 - Organic compounds in body, 11, 12 - Os calcis, 195 - innominatum, 161, 162 - magnum, 181 - uteri, 168 - Osseous labyrinth, 64 - Ossicles of ear, 63, 65 - Osteoblasts, 18 - Osteomalacia, 164, 189 - Osteomyelitis, 193 - Oval window, 63, 64, 65 - Ovaries, 165 - Ovum, 12, 166, 168 - Oxyhemoglobin, 130 - - Paget’s disease, 53 - Pain, sensation of, 47, 81 - Palate, bones of, 48, 54 - cleft, 55 - hard, 55, 59 - soft, 59, 60, 136 - Palmar, arch, 186 - fascia, 184 - Palmaris longus, 182, 183 - Pancreas, 153 - Pancreatic duct, 143, 153 - juice, 143, 144, 153 - Pancreatitis, 153 - Panhysterectomy, 169 - Papillæ of skin, 37, 39 - of tongue, 61 - Paralysis, 79 - Parietal bone, 48, 49 - Parotid gland, 51, 62 - Patella or knee-cap, 19, 192 - Patheticus nerve, 83 - Pectoral muscles, 99, 128 - Pectoralis major, 174 - Pedicles of vertebræ, 89 - Pelvis, 132, 161, _et seq._ - false, 163 - of kidney, 156 - true, 163, 164 - Penis, 160, 165 - Pepsin, 140 - Peptones, 12, 140, 150 - Pericardium, 34, 101, 102 - Perichondrium, 16 - Perineal body, 170 - Perineum, 170 - Perilymph, 64, 65 - Periosteum, 15, 18, 19, 76 - Peripheral resistance, 112, 114 - Peristaltic movements, 138, 143, 146 - Peritoneum, 134 - Permanent teeth, 60 - Peroneal artery, 199 - Peroneus brevis, 197 - longus, 197 - Petrous portion of temporal bone, 51, 52 - Peyer’s patches or glands, 142 - Phalanges of foot, 195 - of hand, 181 - Pharynx, 59, 136, 137 - Physiology, 11 - Phrenic artery, 99, 109 - nerve, 85, 99, 130 - Pia mater, 76 - Pigeon breast, 97 - Pillars of the fauces, 59, 60 - Pink eye, 74 - Pinna, 63 - Pisiform bone, 181 - Pituitary body, 36 - Placenta, 106, 107 - Plantar artery, 199 - fascia, 198 - nerve, 86 - Plantaris, 197 - Plasma of blood, 33, 116, 117 - Platysma myoides, 92 - Pleuræ, 34, 125 - Plexus, 29 - brachial, 84, 85 - cardiac, 87 - cervical, 84 - hypogastric, 87 - lumbar, 84 - sacral, 84, 85 - solar, 87, 153 - Pneumogastric nerve, 84, 110, 127, 153 - Polypi, 58 - Pons Varolii, 78 - Popliteal artery, 198 - nerves, 86, 199 - space, 32, 198 - Popliteus muscle, 198 - Portal circulation, 110 - vein, 110, 150 - Pott’s disease, 91 - fracture, 180, 195 - Poupart’s ligament, 132 - Prepatella bursa, 192 - Prepuce, 165 - Presbyopia, 73 - Presternal notch, 171 - Procreating glands, 165 - Profunda artery, 175, 186 - femoris artery, 198 - Promontory of the sacrum, 90 - Pronator quadratus, 182, 183 - radii teres, 182, 183 - Prostate gland, 164, 165 - Proteins, 11, 26, 33, 140, 144, 147, 148 - Protoplasm, 12, 13 - Psoas magnus, 189, 190 - parvus, 190 - Ptosis of liver, 152 - of upper lid, 74 - Ptyalin, 61, 136 - Pubes, 161, 163 - Pudic artery, 168 - Pulmonary artery, 106, 110 - circulation, 110 - valves, 104 - veins, 105, 110 - Pulse, 112, 113, 114, 115 - Pulse, causes, 112 - dicrotic, 113 - rate, 111, 113, 114 - Pupil of eye, 69, 72 - Pus corpuscles, 120 - Pylorus, 138 - Pyramidalis muscle, 134 - Pyramids, Malpighian, 156 - - Quadratus lumborum, 134 - Quadriceps extensor, 190 - - Radial artery, 108, 185 - nerve, 85 - Racemose glands, 35 - Radius, 178, 179 - Râles, 129 - Receptaculum chyli, 32 - Recti muscles of eye, 67, 72 - Rectum, 145, 146 - Rectus abdominis, 133, 134 - capitis anticus major, 93 - femoris, 190 - Red corpuscles, 118, 119 - Reflex action, 83 - Regions, abdominal, 134, 135 - Renal artery, 109 - Rennin, 140 - Respiration, 121, 127, _et seq._ - center of, 78, 130 - effect on air, 129, 130 - effect on blood, 130, 131 - forced, 128, 129 - kinds of, 128 - rate, 128 - sounds, 129 - variations in, 131 - Retching, 140 - Retina, 68, 69, 70 - Rheumatism, 25 - Rhomboideus muscles, 93 - Rickets, 19, 49, 53, 97, 164, 195 - Ribs, 97, 98 - Right lymphatic duct, 31, 32 - Rigor mortis, 22, 23 - Rivinus, ducts of, 62 - Rodent ulcer, 74 - Rods and cones, 69, 70 - Rolando, fissure of, 75, 82 - Rosary, 97 - Round ligament of uterus, 168 - Round window, 64, 65 - Rupture, 146, 164 - of kidney, 158 - of liver, 152 - of spleen, 154 - of urethra, 160 - - Sacral nerves, 84 - plexus, 84, 85 - vertebræ, 90 - Sacro-sciatic notch, 163 - Sacrum, 90, 161 - Sagittal suture, 48 - Saliva, 61, 136 - Salivary glands, 35, 61, 136 - Salpingectomy, 169 - Saphenous veins, 109, 199 - Sarcolemma, 21 - Sarcoma, 173, 177, 193 - Sartorius muscles, 23, 190 - Scalenus muscles, 93, 128 - Scaphoid bone, ankle, 195 - wrist, 181 - Scapula, 173 - Scarlet fever, 35 - Scarpa’s triangle, 190, 198 - Schwann, white substance of, 37 - Sciatic nerve, 85, 163, 199 - Sclera or sclerotic coat, 68 - Scrotum, 165 - Sebaceous glands, 35, 40, 41 - Sebum, 41 - Second nerve, 70, 83 - Secreting glands, 35 - Segmentation, growth by, 12 - Semen, 165 - Semicircular canals, 64, 66 - Semilunar bones, 181 - cartilages, 193, 194 - valves, 28, 32, 104 - Semimembranosus muscle, 191 - Semitendinosus muscle, 191 - Sense, organs of, 57, _et seq._ - of hearing, 65 - of sight, 70, _et seq._ - of smell, 55, 57, 58, 61 - of taste, 55, 61 - of touch, 45, _et seq._ - Sensory nerves, 82, 83 - tract, 82 - Septum of nose, 55 - deviation of, 58 - Serous membrane, 40 - Serratus magnus, 174 - Serum albumin, 11 - of blood, 117 - Sesamoid bones, 19 - Seventh nerve, 83 - Shin, 194 - Shoulder girdle, 171 - joint, 185 - Sighing, 131 - Sight, sense of, 70, _et seq._ - Sigmoid cavities, 178 - flexure, 145, 146 - Silent areas in brain, 82 - Silver fork deformity, 180 - Sinuses, 28, 49, 51, 52, 78, 105 - Sixth nerve, 68, 83 - Skin, 39, _et seq._ - Skull, bones of, 48, _et seq._ - Small intestine, 141, 142, _et seq._ - Smell, sense of, 55, 57, 58, 61 - Smooth muscle, 21, 25 - Sneezing, 131 - Sobbing, 131 - Soft palate, 59, 60, 136 - Solar plexus, 87, 153 - Soleus, 196 - Solitary glands, 142, 145 - Sounds, 65, 66 - Special senses, 57, _et seq._ - Speech, 122 - center, 82 - Spermatic or ovarian artery, 109, 168 - cords, 165 - Spermatozoa, 165 - Sphenoid bone, 48, 52 - Sphincter of anus, 146 - of pupil, 72 - of pylorus, 138 - Spina bifida, 91 - Spinal accessory nerve, 84, 95, 137 - canal, 91 - column, 88 - cord, 79, _et seq._ - foramen, 89 - nerves, 84, 95 - Spine, 87 - Spinous process of vertebræ, 89 - Spleen, 153, 154 - Splenic artery, 109, 153 - flexure, 145, 146 - vein, 110, 150 - Sprain, 21 - Squamous portion of temporal bone, 51 - Stapes, 63 - Starches, 12, 136, 144 - Steapsin, 144 - Stensen’s duct, 62 - Sterno-cleido-mastoid muscle, 51, 92, 171 - Sternum, 97 - Stimuli, 24 - Stomach, 138 - arteries, 139 - digestion in, 139, 140 - glands, 139 - position, 138 - structure, 139 - Stomach teeth, 60 - Strabismus, 72 - Striated or striped muscle, 21, 23, 25 - Stricture of esophagus, 138 - of urethra, 160 - Sty, 74 - Styloid process of fibula, 195 - of radius, 178, 179 - of temporal bone, 52 - of ulna, 178, 179 - Subarachnoid space, 76, 79 - Subclavian arteries, 94, 99, 107, 108, 185 - veins, 109 - Subclavius muscle, 173 - Subdural space, 76 - Sublingual gland, 56, 62 - Submaxillary gland, 56, 62 - Succus entericus, 143, 144 - Sugar in urine, 151, 158 - Superciliary ridges, 49 - Supinator brevis, 182, 184 - longus, 182, 184 - Supraorbital foramen or notch, 49 - vessels and nerve, 49 - Suprarenal artery, 109 - capsules, 36, 154 - Suprascapular artery, 94 - nerve, 186 - Suspensory ligament of lens, 70, 72 - of liver, 149 - Sutures, 48, 53 - coronal, 48 - lambdoidal, 48 - sagittal, 48 - Sweat, composition, 42 - functions, 42 - glands, 35, 42 - nervous control of, 42 - quantity, 43 - Sylvius, fissure of, 75 - Sympathetic nerve, 87, 110, 127, 137, 143, 145, 168 - system, 75, 87 - Symphysis pubis, 163 - Synovial fluid, 20, 34 - membrane, 20 - Syphilis, 35, 58, 122, 152, 182, 194 - Systemic circulation, 105, 106, 107, _et seq._, 112, 113 - Systole, 104, 106, 112 - - T-fracture, 177, 193 - Tablets of skull, 20, 48 - Tactile corpuscles, 37, 39, 46 - Tarsus or ankle, 195 - Taste buds, 61 - nerves of, 61 - sense of, 55, 61 - Tears, 68 - Teeth, 27, 60 - Temperature of body, 43 - regulation of, 43 - sensation of, 47 - variations in, 44 - Temporal bone, 48, 51 - muscle, 50, 51, 55 - Temporary or milk teeth, 60 - Tendo Achillis, 195, 197 - Tendons, 15, 23 - Tenth nerve, 84 - Testes or testicles, 165 - Third nerve, 68, 72, 83 - Thoracic aorta, 99, 107, 109 - duct, 31 - nerves, 186 - Thoracic cutaneous nerve, 100 - Thorax, 96 - Thymus gland, 36, 124 - Thyro-arytenoid ligaments, 122 - Thyroid axis, 108 - cartilage, 121 - gland, 36, 124 - Tibia or shin bone, 194 - Tibial artery, 198 - nerve, 76, 87, 199 - Tibialis anticus, 197 - Tissues, areolar, 15 - bony, 13, 17 - cartilaginous, 13 - connective, 13, 15 - differentiation of, 13 - elastic, 15 - epithelial, 13 - fibrous, 15 - muscular, 13 - nervous, 13, 36 - Tongue, 46, 59, 60 - tie, 62 - Tonsillitis, 35, 62 - Tonsils, 59, 62 - Torticollis, 92 - Touch, corpuscles, 37, 39, 46 - sense of, 45, _et seq._ - Trachea, 123 - Tracheotomy, 123 - Transudation of lymph, 33 - Transversalis muscle, 133 - colli artery, 94 - Transverse colon, 145 - processes of vertebræ, 89 - Trapezium, 181 - Trapezius, 93, 171 - Trapezoid bone, 181 - Triangular cartilage, 57 - Triceps, 176, 177 - Tricuspid valve, 104 - Trifacial nerve, 61, 83 - Trochanters, 189 - Trochlear surface of femur, 189 - of humerus, 175 - True pelvis, 163, 164 - ribs, 97 - Trypsin, 144 - Tuberculosis, 35, 122, 155, 159, 168, 182, 193, 194, 196 - Tuberosities of humerus, 175 - of tibia, 194 - Tuberosity of ischium, 163 - of radius, 178 - Tubuli lactiferi, 100 - Tumor albus, 194 - Tumors, 100, 175 - Tunica vaginalis oculi, 67 - Turbinated bones, 48, 53, 54 - Twelfth nerve, 84 - Tympanum, 51, 63 - Typhoid fever, 142, 154 - - Ulcer, 139 - Ulna, 177, 178, 185 - Ulnar artery, 108 - nerve, 85, 175, 186 - Umbilical artery, 107 - region, 135 - vein, 106 - Unciform bone, 181 - Unstriated or unstriped muscle, 21, 22, 25 - Upper extremities, 171, _et seq._ - Urea, 148, 152, 158 - Ureters, 155, 156, 159 - Urethra, 159, 160, 165 - Urinary apparatus, 155, _et seq._ - Urine, 156, _et seq._ - Uterine artery, 168 - Uterus, 167, 168 - Uvula, 59 - - Vagina, 168 - Vagus or pneumogastric nerves, 84, 110, 111, 130 - Valves, 103 - aortic, 104 - bicuspid or mitral, 104 - coronary, 105 - Eustachian, 106, 107 - ileo-cecal, 142, 145 - of lymphatic vessels, 31, 32, 33 - of veins, 28 - pulmonary, 104 - semilunar, 28, 32, 104 - tricuspid, 104 - Valvulæ conniventes, 142 - Varicose veins, 109, 113, 199 - Vas deferens, 165 - Vasa nervorum, 37 - vasorum, 29 - Vasoconstrictor nerves, 115 - dilator nerves, 115 - motor nerves, 29, 78, 115 - Vascular system, 107, et seq. - Vastus externus, 190 - internus, 190 - Veins, 27, 28, 29, 109 - basilic, 109 - deep, 28 - gastric, 110, 150 - hemorrhoidal, 146 - hepatic, 110, 150 - iliac, common, 109 - inferior vena cava, 105, 109, 150 - innominate, 109 - intralobular, 150 - jugular, 109 - median, 109 - cephalic, 109 - mesenteric, 110, 150 - portal, 110, 150 - pulmonary, 105, 110 - saphenous, 109, 199 - splenic, 110, 150 - subclavian, 109 - superficial, 28 - superior vena cava, 105, 109 - umbilical, 106 - valves, 28 - varicosity, 109, 113, 199 - Vena cava, inferior, 105, 109, 150 - superior, 105, 109 - Venæ comites, 27, 113 - Ventricles of brain, 75, 79 - of heart, 103 - Vermiform appendix, 145 - Vertebra prominens, 91 - Vertebræ, 88, _et seq._ - Vertebral arteries, 77 - Vesiculæ seminales, 165 - Vestibule of labyrinth, 64, 65 - Vicarious function of glands, 35 - Villi, 142 - Viscera, abdominal, 135, _et seq._ - Visual center, 81 - Vital capacity, 129 - Vitreous humor, 70 - Vocal cords, 122 - Volvulus, 146 - Voluntary muscle, 21, 23 - Vomer, 48, 55 - Vomiting, 140 - Vulva, 169 - - Wharton’s duct, 62 - White corpuscles or leucocytes, 27, 33, 34, 119, 120 - White substance of Schwann, 37 - matter of brain and cord, 75, 76, 78, 80, 81 - Willis, circle of, 78, 108 - Wisdom teeth, 60 - Wormian bones, 19, 49 - Wrist, 180 - joint, 185 - Wry neck or torticollis, 92 - - Yawning, 131 - - Zygomatic process of temporal bone, 51, 54 - - - - -SAUNDERS’ BOOKS FOR NURSES - - - PAGE - Aikens’ Clinical Studies for Nurses 3 - Aikens’ Hospital Management 3 - Aikens’ Primary Studies for Nurses 3 - Aikens’ Training School Methods and the Head Nurse 3 - Beck’s Reference Handbook for Nurses 4 - Boyd’s State Registration for Nurses 4 - Davis’ Obstetric and Gynecologic Nursing 5 - DeLee’s Obstetrics for Nurses 5 - Dorland’s Medical Dictionaries 7, 8 - Fiske’s Anatomy and Physiology for Nurses 4 - Fowler’s Operating Room and the Patient 4 - Friedenwald and Ruhrah on Diet 6 - Galbraith’s Four Epoch’s of Woman’s Life 6 - Galbraith’s Hygiene and Physical Training for Women 6 - Grafstrom’s Mechano-therapy (Massage) 8 - Griffith’s Care of the Baby 8 - Hoxie’s Medicine for Nurses 8 - Lewis’ Anatomy and Physiology for Nurses 7 - Macfarlane’s Gynecology for Nurses 5 - Manhattan Hospital Eye, Ear, Nose and Throat Nursing 6 - McCombs’ Diseases of Children for Nurses 7 - McKenzie’s Exercise in Education and Medicine 5 - Morris’ Essentials of Materia Medica 8 - Morrow’s Immediate Care of Injured 8 - Nancrede’s Essentials of Anatomy 8 - Paul’s Materia Medica for Nurses 8 - Paul’s Nursing in the Acute Infectious Fevers 8 - Pyle’s Personal Hygiene 8 - Register’s Fever Nursing 8 - Stoney’s Bacteriology and Surgical Technic 2 - Stoney’s Materia Medica for Nurses 2 - Stoney’s Nursing 2 - Wilson’s Reference Handbook of Obstetric Nursing 7 - - W. B. SAUNDERS COMPANY - 925 Walnut Street Philadelphia - London: 9, Henrietta Street, Covent Garden - - -Stoney’s Nursing - - NEW (4th) EDITION - -In this excellent volume the author explains the entire range of -_private_ nursing as distinguished from _hospital_ nursing; and the -nurse is given definite directions how best to meet the various -emergencies. _The American Journal of Nursing_ says it “is the -fullest and most complete” and “may well be recommended as being of -great general usefulness. The best chapter is the one on observation -of symptoms which is very thorough.” There are directions how to -_improvise_ everything ordinarily needed in the sick room. - - =Practical Points in Nursing.= By EMILY M. A. - STONEY, Superintendent of the Training School for - Nurses in the Carney Hospital, South Boston, Mass. - 12mo, 495 pages, illustrated. - Cloth, $1.75 net. - - -Stoney’s Materia Medica - - NEW (3d) EDITION - -Stoney’s Materia Medica was written by a head nurse who knows just -what the nurse needs. _American Medicine_ says it contains “all the -information in regards to drugs that a nurse should possess. * * * The -treatment of poisoning is stated in a manner that will permit of its -being carried out thoroughly and intelligently.” - - =Materia Medica for Nurses.= By EMILY M. A. - STONEY, Superintendent of the Training School - for Nurses in the Carney Hospital, South Boston, - Mass. 12mo volume of 300 pages. - Cloth, $1.50 net. - - -Stoney’s Surgical Technic - - NEW (3d) EDITION - -The first part of the book is devoted to Bacteriology and Antiseptics; -the second part to Surgical Technic, Signs of Death, Autopsies, -Bandaging and Dressings, Obstetric Nursing, Care of Infants, etc., -Hygiene and Personal Conduct of the Nurse, etc. The New York _Medical -Record_ says it “is a very practical book which presents the subjects -stated in its title in a concise manner.” - - =Bacteriology and Surgical Technic for Nurses.= By - EMILY M. A. STONEY. Revised by FREDERIC R. GRIFFITH, - M. D., New York 12mo volume of 300 pages, fully - illustrated. - Cloth, $1.50 net. - - - Aikens’ Hospital Management JUST READY - -This is just the work for hospital superintendents, training-school -principals, physicians, and all who are actively interested in hospital -administration. Each chapter has been written by one specially fitted -to write upon that particular phase of the subject; and Miss Aikens has -brought the various chapters into a harmonious whole. - - =Hospital Management.= Arranged and edited by - CHARLOTTE A. AIKENS, formerly Director of Sibley - Memorial Hospital, Washington, D. C. 12mo of 488 - pages, illustrated. - Cloth, $3.00 net - - -Aikens’ Primary Studies for Nurses - -_Trained Nurse and Hospital Review_ says: “It is safe to say that any -pupil who has mastered even the major portion of this work would be one -of the best prepared first year pupils who ever stood for examination.” - - =Primary Studies for Nurses.= By CHARLOTTE - A. AIKENS, formerly Director of Sibley Memorial - Hospital, Washington, D. C. 12mo of 435 pages, - illustrated. - Cloth, $1.75 net. - - -Aikens’ Training-School Methods and the Head Nurse - -This work not only tells how to teach, but also what should be taught -the nurse and _how much_. The _Medical Record_ says: “This book is -original, breezy and healthy.” - - =Hospital Training-School Methods and the Head - Nurse.= By CHARLOTTE A. AIKENS, formerly - Director of Sibley Memorial Hospital, Washington, - D. C. 12mo of 267 pages. - Cloth, $1.50 net. - - -Aikens’ Clinical Studies for Nurses - -ILLUSTRATED - -This new work is written on the same lines as the author’s successful -work for primary students, taking up the studies the nurse must pursue -during the second and third years. - - =Clinical Studies for Nurses.= By CHARLOTTE - A. AIKENS, formerly Director of Sibley Memorial - Hospital, Washington, D. C. 12mo of 512 pages, - illustrated. - Cloth, $2.00 net. - - -Fowler’s Operating Room NEW (2d) EDITION - -Dr. Fowler’s work contains all information of a surgical nature that a -nurse must know in order to attain the highest efficiency. _Canadian -Journal of Medicine and Surgery_ says: “We find compactly and clearly -stated just those thousand and one things which when required are so -hard to locate.” - - =The Operating Room and the Patient.= - By RUSSELL S. FOWLER, M. D., Professor of - Surgery, Brooklyn Postgraduate Medical School. - Octavo of 284 pages, with original illustrations. - Cloth, $2.00 net. - - -Fiske’s Anatomy and Physiology JUST READY - -Miss Fiske weaves the physiology in with the anatomy, and in such a way -that both anatomy and function are readily understood and retained by -the reader. - - =Anatomy and Physiology for Nurses.= - By ANNETTE FISKE. A. M., Graduate of the - Waltham Training School for Nurses, Massachusetts. - 12mo of 250 pages, illustrated. - - -Beck’s Reference Handbook NEW (2d) EDITION - -This book contains all the information that a nurse requires to carry -out any directions given by the physician. The _Montreal Medical -Journal_ says it is “cleverly systematized and shows close observation -of the sickroom and hospital regime.” - - =A Reference Handbook for Nurses.= - By AMANDA K. BECK, Graduate of the Illinois - Training School for Nurses, Chicago, Ill. 32mo - volume of 200 pages. Bound in flexible leather, - $1.25 net. - - -Boyd’s State Registration for Nurses - -This book tells the nurse just what she must know in order to obtain -a certificate in any State. It presents comparative summaries of the -laws, requirements, fees, exceptions and restrictions, violations and -their penalties. The work will also form a serviceable basis for the -drafting of laws. - - =State Registration for Nurses.= By LOUIE - CROFT BOYD, R. N., Graduate Colorado Training - School for Nurses. - Price, 50 cents net. - - -DeLee’s Obstetrics for Nurses THIRD EDITION - -Dr. DeLee’s book really considers two subjects--obstetrics for nurses -and actual obstetric nursing. _Trained Nurse and Hospital Review_ says -the “book abounds with practical suggestions, and they are given with -such clearness that they cannot fail to leave their impress.” - - =Obstetrics for Nurses.= By JOSEPH B. - DELEE, M. D., Professor of Obstetrics at the - Northwestern University Medical School, Chicago. - 12mo volume of 512 pages, fully illustrated. - Cloth, $2.50 net. - - -Davis’ Obstetric & Gynecologic Nursing - -THE NEW (3d) EDITION - -_The Trained Nurse and Hospital Review_ says: “This is one of the most -practical and useful books ever presented to the nursing profession.” -The text is illustrated. - - =Obstetric and Gynecologic Nursing.= - By EDWARD P. DAVIS, M. D., Professor of - Obstetrics in the Jefferson Medical College, - Philadelphia. 12mo volume of 436 pages, - illustrated. Buckram, $1.75 net. - - -Macfarlane’s Gynecology for Nurses - -ILLUSTRATED - -_Dr. A. M. Seabrook_, Woman’s Hospital of Philadelphia, says: “It is a -most admirable little book, covering in a concise but attractive way -the subject from the nurse’s standpoint. You certainly keep up to date -in all these matters, and are to be complimented upon your progress and -enterprise.” - - =A Reference Handbook of Gynecology for Nurses.= - By CATHARINE MACFARLANE, M. D., Gynecologist to - the Woman’s Hospital of Philadelphia. 32mo of 150 - pages, with 70 illustrations. - Flexible leather, $1.25 net. - -McKenzie’s Exercise in Education and Medicine - - =Exercise in Education and Medicine.= - By R. TAIT MCKENZIE, B. A., M. D., Professor of - Physical Education, and Director of the Department, - University of Pennsylvania. Octavo of 406 pages, - with 346 illustrations. - Cloth, $3.50 net. - - -Manhattan Hospital Eye, Ear, Nose, and Throat Nursing - -ILLUSTRATED - -This is a practical book, prepared by surgeons who, from their -experience in the operating amphitheatre and at the bedside, have -realized the shortcomings of present nursing books in regard to eye, -ear, nose, and throat nursing. - - =Nursing in Diseases of the Eye, Ear, Nose and - Throat.= By the Committee on Nurses of the Manhattan - Eye, Ear, and Throat Hospital: J. EDWARD GILES, M. - D., Surgeon in Eye Department; ARTHUR B. DUEL, M. - D., (chairman), Surgeon in Ear Department; HARMON - SMITH, M. D., Surgeon in Throat Department. Assisted - by JOHN R. SHANNON, M. D., Assistant Surgeon in - Eye Department; and JOHN R. PAGE, M. D., Assistant - Surgeon in Ear Department. With chapters by HERBERT - B. WILCOX, M. D., Attending Physician to the - Hospital; and Miss EUGENIA D. AYERS, Superintendent - of Nurses. 12mo of 260 pages, illustrated. Cloth, - $1.50 net. - - -Friedenwald and Ruhrah’s Dietetics for Nurses NEW (2d) EDITION - -This work has been prepared to meet the needs of the nurse, both in -training school and after graduation. _American Journal of Nursing_ -says it “is exactly the book for which nurses and others have long and -vainly sought.” - - =Dietetics for Nurses.= By JULIUS - FRIEDENWALD, M. D., Professor of Diseases - of the Stomach, and JOHN RUHRAH, M. D., - Professor of Diseases of Children, College of - Physicians and Surgeons, Baltimore. 12mo volume - of 395 pages. - Cloth, $1.50 net - - -Friedenwald & Ruhrah on Diet THIRD EDITION - - =Diet in Health and Disease.= By JULIUS - FRIEDENWALD, M. D., and JOHN RUHRAH, - M. D. Octavo volume of 764 pages. - Cloth, $4.00 net. - - -Galbraith’s Personal Hygiene and Physical Training for Women - -JUST ISSUED - - =Personal Hygiene and Physical Training for Women.= - By ANNA M. GALBRAITH, M. D., Fellow New York Academy - of Medicine. 12mo of 371 pages, illustrated. - Cloth, $2.00 net. - - -Galbraith’s Four Epochs of Woman’s Life THE NEW (2d) EDITION - - =The Four Epochs of Woman’s Life.= By ANNA - M. GALBRAITH, M. D. With an Introductory Note - by JOHN H. MUSSER, M. D., University of - Pennsylvania. 12mo of 247 pages. - Cloth, $1.50 net. - - -McCombs’ Diseases of Children for Nurses - -JUST ISSUED--NEW (2d) EDITION - -Dr. McCombs’ experience in lecturing to nurses has enabled him to -emphasize _just those points that nurses most need to know. National -Hospital Record_ says: “We have needed a good book on children’s -diseases and this volume admirably fills the want.” The nurse’s side -has been written by head nurses, very valuable being the work of Miss -Jennie Manly. - - =Diseases of Children for Nurses.= - By ROBERT S. MCCOMBS, M. D., Instructor of - Nurses at the Children’s Hospital of Philadelphia. - 12mo of 470 pages, illustrated. - Cloth, $2.00 net - - -Wilson’s Obstetric Nursing - -In Dr. Wilson’s work the entire subject is covered from the beginning -of pregnancy, its course, signs, labor, its actual accomplishment, the -puerperium and care of the infant. _American Journal of Obstetrics_ -says: “Every page emphasizes the nurse’s relation to the case.” - - =A Reference Handbook of Obstetric Nursing.= - By W. REYNOLDS WILSON, M. D., Visiting - Physician to the Philadelphia Lying-in Charity. 32mo - of 355 pages, illustrated. - Flexible leather, $1.25 net. - - -American Pocket Dictionary NEW (6th) EDITION - -The _Trained Nurse and Hospital Review_ says: “We have had many -occasions to refer to this dictionary, and in every instance we have -found the desired information.” - - =American Pocket Medical Dictionary.= Edited by - W. A. NEWMAN DORLAND, A. M., M. D., Loyola - University, Chicago. - Flexible leather, gold edges, $1.00 net; - with patent thumb index, $1.25 net. - - -Lewis’ Anatomy and Physiology SECOND EDITION - -_Nurses Journal of Pacific Coast_ says “it is not in any sense -rudimentary, but comprehensive in its treatment of the subjects.” The -low price makes this book particularly attractive. - - =Anatomy and Physiology for Nurses.= - By LEROY LEWIS, M. D., Lecturer on Anatomy and - Physiology for Nurses, Lewis Hospital, Bay City, - Mich. 12mo of 375 pages, 150 illustrations. - Cloth, $1.75 net. - - -Dorland’s Illustrated Dictionary NEW (5th) EDITION - - =The American Illustrated Medical Dictionary.= - Edited by W. A. N. DORLAND, M. D. Large - octavo of 876 pages, 293 illustrations, 119 in - colors. Flexible leather, $4.50 net; thumb indexed, - $5.00 net. - - -Paul’s Materia Medica - - =A Text-Book of Materia Medica for Nurses.= - By GEORGE P. PAUL, M. D., Samaritan Hospital, - Troy, N. Y. 12mo of 240 pages. - Cloth, $1.50 net. - - -Paul’s Fever Nursing - - =Nursing in the Acute Infectious Fevers.= - By GEORGE P. PAUL, M. D. - Cloth, $1.00 net. - - -Hoxie’s Medicine for Nurses - - =Practice of Medicine for Nurses.= - By GEORGE HOWARD HOXIE, M. D., University - of Kansas. With a chapter on Technic of Nursing - by PEARL L. LAPTAD. 12mo of 284 pages, - illustrated. - Cloth, $1.50 net. - - -Grafstrom’s Mechano-therapy SECOND EDITION - - =Mechano-therapy (Massage and Medical - Gymnastics).= By AXEL V. GRAFSTROM, - B. Sc., M. D., 12mo, 200 pages. - Cloth, $1.25 net. - - -Nancrede’s Anatomy NEW (7th) EDITION - - =Essentials of Anatomy.= CHARLES B. G. - DENANCREDE, M. D., University of Michigan. - 12mo, 400 pages, 180 illustrations. - Cloth, $1.00 net. - - -Morrow’s Immediate Care of Injured - - =Immediate Care of the Injured.= By ALBERT - S. MORROW, M. D., New York City Home for - Aged and Infirm. Octavo of 340 pages, with 238 - illustrations. Cloth, $2.50 net. - - -Register’s Fever Nursing - - =A Text-Book on Practical Fever Nursing.= - By EDWARD C. REGISTER, M. D., North Carolina - Medical College. Octavo of 350 pages, illustrated. - Cloth, $2.50 net. - - -Pyle’s Personal Hygiene NEW (4th) EDITION - - =A Manual of Personal Hygiene.= Edited by - WALTER L. PYLE, M. D. Wills Eye Hospital, - Philadelphia. 12mo, 472 pages, illus. - $1.50 net. - - -Morris’ Materia Medica NEW (7th) EDITION - - =Essentials of Materia Medica, Therapeutics, - and Prescription Writing.= By HENRY MORRIS, - M. D. Revised by W. A. BASTEDO, M. D., - Columbia University, N. Y. 12mo of 300 pages, - illustrated. Cloth, $1.00 net. - -Griffith’s Care of the Baby JUST ISSUED NEW (5th) EDITION - - =The Care of the Baby.= By J. P. CROZER - GRIFFITH, M. D., University of Pennsylvania. - 12mo of 455 pages, illustrated. - Cloth, $1.50 net. - -*** END OF THE PROJECT GUTENBERG EBOOK STRUCTURE AND FUNCTIONS OF THE -BODY *** - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the -United States without permission and without paying copyright -royalties. Special rules, set forth in the General Terms of Use part -of this license, apply to copying and distributing Project -Gutenberg-tm electronic works to protect the PROJECT GUTENBERG-tm -concept and trademark. Project Gutenberg is a registered trademark, -and may not be used if you charge for an eBook, except by following -the terms of the trademark license, including paying royalties for use -of the Project Gutenberg trademark. If you do not charge anything for -copies of this eBook, complying with the trademark license is very -easy. You may use this eBook for nearly any purpose such as creation -of derivative works, reports, performances and research. Project -Gutenberg eBooks may be modified and printed and given away--you may -do practically ANYTHING in the United States with eBooks not protected -by U.S. copyright law. Redistribution is subject to the trademark -license, especially commercial redistribution. - -START: FULL LICENSE - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full -Project Gutenberg-tm License available with this file or online at -www.gutenberg.org/license. - -Section 1. General Terms of Use and Redistributing Project -Gutenberg-tm electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or -destroy all copies of Project Gutenberg-tm electronic works in your -possession. If you paid a fee for obtaining a copy of or access to a -Project Gutenberg-tm electronic work and you do not agree to be bound -by the terms of this agreement, you may obtain a refund from the -person or entity to whom you paid the fee as set forth in paragraph -1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this -agreement and help preserve free future access to Project Gutenberg-tm -electronic works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the -Foundation" or PGLAF), owns a compilation copyright in the collection -of Project Gutenberg-tm electronic works. Nearly all the individual -works in the collection are in the public domain in the United -States. If an individual work is unprotected by copyright law in the -United States and you are located in the United States, we do not -claim a right to prevent you from copying, distributing, performing, -displaying or creating derivative works based on the work as long as -all references to Project Gutenberg are removed. Of course, we hope -that you will support the Project Gutenberg-tm mission of promoting -free access to electronic works by freely sharing Project Gutenberg-tm -works in compliance with the terms of this agreement for keeping the -Project Gutenberg-tm name associated with the work. You can easily -comply with the terms of this agreement by keeping this work in the -same format with its attached full Project Gutenberg-tm License when -you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are -in a constant state of change. If you are outside the United States, -check the laws of your country in addition to the terms of this -agreement before downloading, copying, displaying, performing, -distributing or creating derivative works based on this work or any -other Project Gutenberg-tm work. The Foundation makes no -representations concerning the copyright status of any work in any -country other than the United States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other -immediate access to, the full Project Gutenberg-tm License must appear -prominently whenever any copy of a Project Gutenberg-tm work (any work -on which the phrase "Project Gutenberg" appears, or with which the -phrase "Project Gutenberg" is associated) is accessed, displayed, -performed, viewed, copied or distributed: - - This eBook is for the use of anyone anywhere in the United States and - most other parts of the world at no cost and with almost no - restrictions whatsoever. You may copy it, give it away or re-use it - under the terms of the Project Gutenberg License included with this - eBook or online at www.gutenberg.org. If you are not located in the - United States, you will have to check the laws of the country where - you are located before using this eBook. - -1.E.2. If an individual Project Gutenberg-tm electronic work is -derived from texts not protected by U.S. copyright law (does not -contain a notice indicating that it is posted with permission of the -copyright holder), the work can be copied and distributed to anyone in -the United States without paying any fees or charges. If you are -redistributing or providing access to a work with the phrase "Project -Gutenberg" associated with or appearing on the work, you must comply -either with the requirements of paragraphs 1.E.1 through 1.E.7 or -obtain permission for the use of the work and the Project Gutenberg-tm -trademark as set forth in paragraphs 1.E.8 or 1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any -additional terms imposed by the copyright holder. Additional terms -will be linked to the Project Gutenberg-tm License for all works -posted with the permission of the copyright holder found at the -beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including -any word processing or hypertext form. However, if you provide access -to or distribute copies of a Project Gutenberg-tm work in a format -other than "Plain Vanilla ASCII" or other format used in the official -version posted on the official Project Gutenberg-tm website -(www.gutenberg.org), you must, at no additional cost, fee or expense -to the user, provide a copy, a means of exporting a copy, or a means -of obtaining a copy upon request, of the work in its original "Plain -Vanilla ASCII" or other form. Any alternate format must include the -full Project Gutenberg-tm License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works -provided that: - -* You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is owed - to the owner of the Project Gutenberg-tm trademark, but he has - agreed to donate royalties under this paragraph to the Project - Gutenberg Literary Archive Foundation. Royalty payments must be paid - within 60 days following each date on which you prepare (or are - legally required to prepare) your periodic tax returns. Royalty - payments should be clearly marked as such and sent to the Project - Gutenberg Literary Archive Foundation at the address specified in - Section 4, "Information about donations to the Project Gutenberg - Literary Archive Foundation." - -* You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or destroy all - copies of the works possessed in a physical medium and discontinue - all use of and all access to other copies of Project Gutenberg-tm - works. - -* You provide, in accordance with paragraph 1.F.3, a full refund of - any money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days of - receipt of the work. - -* You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project -Gutenberg-tm electronic work or group of works on different terms than -are set forth in this agreement, you must obtain permission in writing -from the Project Gutenberg Literary Archive Foundation, the manager of -the Project Gutenberg-tm trademark. Contact the Foundation as set -forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -works not protected by U.S. copyright law in creating the Project -Gutenberg-tm collection. Despite these efforts, Project Gutenberg-tm -electronic works, and the medium on which they may be stored, may -contain "Defects," such as, but not limited to, incomplete, inaccurate -or corrupt data, transcription errors, a copyright or other -intellectual property infringement, a defective or damaged disk or -other medium, a computer virus, or computer codes that damage or -cannot be read by your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium -with your written explanation. The person or entity that provided you -with the defective work may elect to provide a replacement copy in -lieu of a refund. If you received the work electronically, the person -or entity providing it to you may choose to give you a second -opportunity to receive the work electronically in lieu of a refund. If -the second copy is also defective, you may demand a refund in writing -without further opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO -OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT -LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of -damages. If any disclaimer or limitation set forth in this agreement -violates the law of the state applicable to this agreement, the -agreement shall be interpreted to make the maximum disclaimer or -limitation permitted by the applicable state law. The invalidity or -unenforceability of any provision of this agreement shall not void the -remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in -accordance with this agreement, and any volunteers associated with the -production, promotion and distribution of Project Gutenberg-tm -electronic works, harmless from all liability, costs and expenses, -including legal fees, that arise directly or indirectly from any of -the following which you do or cause to occur: (a) distribution of this -or any Project Gutenberg-tm work, (b) alteration, modification, or -additions or deletions to any Project Gutenberg-tm work, and (c) any -Defect you cause. - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of -computers including obsolete, old, middle-aged and new computers. It -exists because of the efforts of hundreds of volunteers and donations -from people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future -generations. To learn more about the Project Gutenberg Literary -Archive Foundation and how your efforts and donations can help, see -Sections 3 and 4 and the Foundation information page at -www.gutenberg.org - -Section 3. Information about the Project Gutenberg Literary -Archive Foundation - -The Project Gutenberg Literary Archive Foundation is a non-profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg Literary -Archive Foundation are tax deductible to the full extent permitted by -U.S. federal laws and your state's laws. - -The Foundation's business office is located at 809 North 1500 West, -Salt Lake City, UT 84116, (801) 596-1887. Email contact links and up -to date contact information can be found at the Foundation's website -and official page at www.gutenberg.org/contact - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without -widespread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine-readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To SEND -DONATIONS or determine the status of compliance for any particular -state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. To -donate, please visit: www.gutenberg.org/donate - -Section 5. General Information About Project Gutenberg-tm electronic works - -Professor Michael S. Hart was the originator of the Project -Gutenberg-tm concept of a library of electronic works that could be -freely shared with anyone. For forty years, he produced and -distributed Project Gutenberg-tm eBooks with only a loose network of -volunteer support. - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as not protected by copyright in -the U.S. unless a copyright notice is included. Thus, we do not -necessarily keep eBooks in compliance with any particular paper -edition. - -Most people start at our website which has the main PG search -facility: www.gutenberg.org - -This website includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. |