Page images

Neck.--1. Latissimus colli, or platysma Muscles peculiar to the male organs of gemyoides ; 2. sterno-cleido-mastoideus. neration.-1. Cremaster; 2. erector penis

Tongue and thyroid cartilage.-1. Omo. 3. accelerator ; 4. compressor prostatæ. hyoidens ; 2. sternohyoideus; 3. sternothy. Muscles peculiar to the female organs of reoideus; 4. hyothyreoideus ; 5. musculus generation.--1. Erector clitoridis ; 2. sphincglandula thyreoideæ ; 6. stylohyoideus ; 7. ter vaginæ ; 3. depressor urethræ. styloglossus ; 8. mylohyoideus; 9. genio The whole number of muscles of the trunk hyoideus ; 10. hyoglossus ; 11. gevioglossus; 105. 12. lingualis.

Muscles of the upper extremity.--Shoulder. Muscles of the pharynx and palate.-1. 1. Pectoralis major; 2. pectoralis minor; Stylopharyngeus; 2. constrictor pharyngis S. subclavius; 4. serratus magnus; 5. trape. superior; 3. constrictor medius ; 4. con zius; 6. latissimus dorsi ; 7. rbomboideus strictor inferior; 5. salpingo-pharyngeus; minor ; 8. rhomboideus major; 9. levator 6. palato-pharyngeus ; 7. constrictor isthmianguli scapulæ ; 10. deltoides; 11. suprafaucium ; 8. levator palati mollis ; 9. cir- spinatus ; 12. infraspinatus; 13. teres macumflexus palati ; 10. azygus uvulæ. jor; 14. teres minor; 15. subscapularis.

Muscles of the larynx.—1. Cricothyreoi Arm.--1. Biceps flexor cubiti; 2. brachideus ; 2. crico-arytenoideus posticus; 3. alis internus ; 3. coracobrachialis ; 4. triceps crico-arytenoideus lateralis; 4. arytenoi- extensor cubiti; 5. anconeus. deus obliquus; 5. arytenoideus transversus; Fore-arm.—1. Supinator radii longus ; 2, 6. thyreo-arytenoideus; 7. thyreo-epiglot- 3. extensor carpi radialis longior et brevior; ticns.

4. extensor carpi ulnaris ; 5. extensor comThe whole number of muscles about the munis digitorum manus; 6. extensor prohead, neck, and throat, is therefore 72.

prius auricularis ; 7. abductor longus pollicis Muscles of the abdomen.-1. Obliquus ex manus; 8. extensor major pollicis manus ; ternus abdominis; 2. obliquus internus ab- 9. extensor minor pollicis ; 10. indicator; dominis ; 3. transversalis abdominis ; 4. rec 11, flexor carpi ulnaris ; 12. palmaris longus; tus abdominis ; 5. pyramidalis; 6. dia- 13. flexor carpi radialis; 14. pronator raphragma or septum transversum.

dii teres ; 15. flexor digitorum sublimis, or Muscles of the thorax.-1. Sterno costalis, perforatus; 16. flexor profundus, or peror triangularis sterni; 2. serratus posticus forans ; 17, to 20. musculi lumbricales ; superior; 3. serratus posticus inferior; 4, 21. flexor longus pollicis manus ; 29. supi5, 6. scalenus anterior, medius, and poste- nator radii brevis ; 23. pronator radii quarior; 7 to 18. levatores breviores costarum; dratus. 19 to 21. levatores longiores costarum; Muscles of the hand.--1. Abductor brevis 29. intercostales externi; 23, intercostales pollicis manus; 2. opponens pollicis mainterni ; 24. quadratus lumborum.

nus; 3. flexor brevis pollicis ; 4. adductor Muscles moving the head and spine.-1. pollicis; 5. palmaris brevis; 6. abductor Splenius capitis ; 2. splenins cervicis; 3. bi- digiti minimi ; 7. flexor proprius digiti miventer cervicis ; 4. complexus; 5. trachelo- nimi; 8. adductor ossis metacarpi digitimastoideus; 6. transversus cervicis; 7. cer- minimi ; 9, to 11. interossei interni manus; vicis descendens; 8. longissimus dorsi; 12, to 15. interossei externi manus. 9. sacrolumbalis ; 10), spinalis cervicis ; 11. The muscles of the upper extremity spinalis dorsi ; 12. multifidus spinæ; 13 to 22. interspinales cervicis ; 23 to 28. inter Muscles of the thigh.-1. Tensor fasciæ spinales lumborum; 29. rectus capitis posti- latæ; 2. gluteus maximus; 3. gluteus mecus major; 30. rectus capitis posticus minor; dius; 4. gluteus minimus; 5. pyriformis ; 31. obliquus capitis superior: S2. obliquus 6,7. geminus superior and inferior; 8. obcapitis inferior; 33. rectus lateralis ; 34. rec turator internus; 9. quadratus femoris ; tus capitis anticus major; 35. rectus anticus 10. biceps flexor cruris ; 11. semitendinominor; 36. longus colli; 37 to 43. inter- sus ; 12. semimembranosus ; 13. psoas mitransversi colli priores ; 44 to 49. intertrans- nor; 14. psoas major ; 15. iliacus interversi colli posteriores; 50 to 57. intertrans. nus; 16. sartorius; 17. gracilis ; 18. recversi dorsi; 58 to 62. intertransversi lum tus extensor cruris ; 19. vastus externus; borum.

20. vastus internus; 21. cruralis ; 22. pecMuscles of the anus and perineum.--1. trans- tineus; 23. triceps adductor femoris ; versus perinei; 2. transversus perinei alter; 24. obturator externus. 3. sphincter ani; 4. levator ani; 5. muscu Muscles of the leg.-1. Gastrocnemius or Ius coccygeus ; 6. curvator coccygis. gemellus ; %. soleus; 3. plantaris ; 4. pop

are 58.

liteus; 5. flexor longus digitorum pedis; greater distance from the attachment of 6 to 9. lumbricales pedis ; 10. flexor lon- the muscles, because their office does not gus hallucis ; 11. tibialis posticus ; 12. pe- require so great a muscular exertion. roneus longus ; 13. peroneus brevis ; 14. ti The tongue is of considerable utility in bialis anticus ; 15. extensor longus digito- contributing to mastication, as it serves to rum pedis ; 16. peroneus tertius.

move the food about in the cavity of the Muscles of the foot.-1. Extensor pro- mouth, and to subject it again to the action prius hallucis; 2. extensor brevis digito of the grinding teeth, when it has escaped rum pedis ; 3. flexor brevis digitorum pe- from between their surfaces. The muscles dis ; 4. abductor hallucis; 5. transversus of this organ, which we have enumerated in pedis; 6. abductor digiti minimi pedis; the myological division of the article, give it 7. flexor brevis digiti minimi pedis ; 8 to 10. a power of motion in every direction. interossei interni pedis ; 11 to 14. inter But the simple act of mastication would ossei externi pedis.

only reduce the food into a powder, or at all The muscles of the lower extremity are events into a dry mass, that could not be 54; and the whole number of the body 289. swallowed without great difficulty. To obBut as they are the same on both sides, this viate this inconvenience, it is plentifully must be doubled, which will give 578; an moistened with a watery fluid called saliva, enumeration which is pretty nearly correct. and is thereby converted into a soft paste,

which can be conveyed into the stomach ORGANS CONCERNED IN THE REDUCTION

with perfect facility. The source of this AND ASSIMILATION OF THE FOOD.

fluid is in several glandular bodies situated

near the mouth, and sending excretory ducts Organs of mastication and deglutition. which convey the secreted fluid into that The two jaws, with their teeth, and the cavity. As the jaws move, their muscles tongue, are the principal agents in the bus compress these glands, and squeeze the siness of mastication.

secreted fluid into the mouth. The tongue The articulation of the condyle of the is constantly employed in bringing again lower jaw with the glenoid cavity of the under the action of the teeth those portions temporal bone, admits of the former part of the food which escape from between being moved in various directions. Its de- them; and the closure of the lips prevenis pression and elevation cause the opening it from falling ont of the mouth. and shutting of the mouth. It can be The true salivary glands are three in numbrought forwards, and carried backwards; ber, on each side of the head. The largest and admits also of being moved to one side is placed in the space left between the ear or the other. It is by a combination of and the lower jaw-bone; and is called, from these various motions that the food is mas- its situation, the parotid. Its duct pierces the ticated, or reduced into a soft and pulpy middle of the cheek. The two others are form. The different teeth, which are placed placed nnder the tongue, and are called the in various parts of the cavity of the mouth, submaxillary and sublingual. Their ducts are adapted, by their form and situation, join to open by a common orifice, at the for various parts of the process of mastica- side of the membrane called the frenum of tion. The anterior ones, which have a thin the tongue, which ties the under surface of cutting edge, and in which the superior that organ to the inside of the lower jaw. overlap the inferior, act like the blades of Besides these large salivary glands, there a pair of scissars. These cut the food into are other small granular bodies, which pour smaller morsels; and serve us also in biting a mucuous fluid into the mouth; these are off a portion from any mass of food which named, according to their situation, glandulæ we may be eating. The back teeth have labiales, buccales, &c. broad bases, furnished with obtuse promi The cavity of the mouth, in which the nences ; and they shut perpendicularly on process of mastication goes on, is not a very each other. These are therefore well adapt. extensive one. There is a small space left ed for the grinding and trituration of the between the cheeks and the teeth exterfood. As their office requires a greater nally; but within the teeth the tongue ocmascular force, they are placed in the back cupies nearly the whole rooin. of the mouth, near to the centre of motion, boundary is formed by the palate or roof of and where, consequently, the action of the the mouth, and the lower by the surface of muscles is telt with the greatest effect. The the tongue. The mouth opeus behind by cutting teeth are placeil in front, at a a tolerably fire comnmunication, into a mem

The upper


branous bag, called the pliarynx. The sur- traneous body should find admission. These tace of the mouth is every where covered points are both attained by means of a by a soft and smooth membrane. This is of strictly mechanical contrivance; by a struccourse kept constantly in a moist state, as ture which produces the required effect, the glands above enumerated continually independently of the will of the animal, and pour more or less of their secretion into merely in consequence of those motions the cavity. The membrane of the mouth is which the organs perform in the office of continuous with the external surface of the deglutition. At the back of the tongue, body; but the skin assumes a more delicate and just in front of the glottis, is a cartilaorganization, as must be apparent to every ginous valve called the epiglottis. When body, from the change of colour at the lips. the parts are at rest, this valve stands per

Bag of the pharynx.— The masticated ali- pendicular, and consequently does not interment is collected on the back of the tongue, fere with the passage of air into the windwhich is then carried upwards, and back. pipe. In the act of swallowing, the tongue, wards to discharge it into the pharynx. Tiris is carried backwards, and the windpipe is bag is covered by muscular fibres (forming drawn up : hence the epiglottis becomes the muscles called constrictores pharyngis) mechanically applied over the opening, and which contract, successively, in order to at this moment the food enters the pharynx propel the food towards the stomach. But over it, and by its pressure closes the aperas there are several organs communicating ture still more completely. As soon as the with the pharynx, the food might pass in a food has passed, the tongue and windpipe wrong direction if the parts were not so con resume their former position, the elasticity trived as to prevent such occurrences. of the cartillage restores it to the erect state,

In the upper and anterior part of the and the glottis is again free for the continupharynx, the nostrils open by two large and ance of respiration. So completely does free apertures. Between these and the en- this simple mechanism answer the proposed trance from the mouth, is found a fleshy and end, that although every morsel of food moveable curtain, called the soft palate, or passes over the glottis, the accident of any velum pendulum palati. There is a small portion going the wrong way, as it is termbody of a pointed figure projecting from the ed, is comparatively rare, and can only arise middle of this organ, and known by the from our being imprudent enough to laugh name of the uvula. This curtain and the or talk while we are swallowing. In either uvula can be easily seen in the throat of a of these cases air must pass out of the traliving person. It admits of being elevated chea, and by so doing, it lifts up the episo as to shut the opening of the nostrils ; and glottis. its action is exemplified in the act of vomita The pharynx opens below into the æso. ing: the food is forcibly thrown into the phagus, a muscular tube, which conveys the pharynx, and would pass mostly into the food into the stomach. The aliment in its nose, were it not prevented by the soft farther progress, goes through different vispalate. From the uvula the membrane is cera contained in the abdomen; and we continued on either side, in an arched form, shall therefore proceed with a description of towards the root of the tongue, and it con- that cavity. tains a glandular body called the tonsil, The term abdomen includes a large porwhich secretes a mucous fluid to lubricate tion of the body. It is bounded above by the parts, and facilitate the passage of the the cartilages of the ribs, and by the dia. aliment. The larynx opens into the pha- pbragm, which separates it from the chest ; rynx, just at the root of the tongue; over at the back part, by the bodies of the lumthis part, which is termed the glottis, every bar vertebra ; in front and at the sides, by morsel of the food must necessarily pass; the abdominal muscles ; and below, by the yet, so exquisitely tender is the membrane bones of the pelvis. of the windpipe, that the contact of the It is every where lined by a membrane smallest extraneous body excites a convul- called the peritoneum. The surface of this sive paroxysm of coughing that does not is perfectly smooth and polished, and moiscease until the offending matter be removed. tened by a serous exhalation produced by Here then are two objects to be effected; the minute arteries of the part. This memthe function of respiration requires that the brane not only lines the cavity of the abdowindpipe should have a free coinınunication men, but also covers all the viscera containwith the external air, while the irritable na. ed in that cavity, so that the exterior surtate of its membrane deman is that no ex- face of each part consists of what anatomists

call its peritoneal coat. Hence the motions attached to a part of the colon; its use is of these parts upon each other, and upon unknown. the surface of the cavity are performed with The small intestine is divided into three perfect facility. The productions of the parts ; the duodenum, jejunum, and ileum: membrane, which give these exterior invest. but this distinction is an arbitrary one, and ments to the viscera, serve also to confine not founded on any difference in structure. them in their relative positions.

It consists of a membranous tube, about an The cavity is subdivided into three regions, inch or an inch and a half in diameter, and the epigastric, which includes all the space four times the length of the subject. Notabove an imaginary line drawn across the withstanding this great length, it is collected belly, from the greatest convexities of the car by means of numerous turnings and convotilages of the seventh true rib; the umbilical, lutions, into a comparatively small space. which is the division between this line and These convolutions of the small intestine another drawn from the anterior superior occupy the chief part of the umbilical and spines of the ilia ; and the hypogastric, which hypogastric regions of the abdomen. They is the space left below the last line. are connected in their situation by means of

The sides of the epigastric region, which a broad folded membrane, called the mesenare the spaces covered by the cartilages of tery. This production of the peritoneum the ribs, are called hypochondria : the sides is about six inches broad at its commenceof the umbilical region are named the loins: nient, but it expands gradually, something and those of the hypogastric the groins. after the manner of a fan, so that it becomes

The stomach is a large membraneous reser broad enough, ultimately, to cover the voir, receiving the food from the æsophagus, whole length of the small intestine. It and retaining it until a certain change, called serves to keep the different convolutions of digestion, is produced. Its figure is conical, the canal in a certain relative position, and as it is largest at the left end, and gradually allows, at the same time, a considerable decreases in size towards the right: these freedom of motion, without any danger of are called the greater and smaller extremi- intangling. In tracing the course of the ties of the stomach. It is also bent in its small intestine, we follow the duodenum course, so that we describe a greater and from the lesser extremity of the stomach, smaller curvature or arch. It has two open- in the right hypochondriuin, making three ings, one close to the diaphragm, called the turns close on the backbone, and then comcardiac, superior, or esophageal ; the other ing out just over the left kidney. The just at the smaller end is called the pyloric, general direction of the canal from this point, or lower orifice. The capacity of the stomach independently of its various turnings and varies from about 5 to 11 pints.

windings, is towards the right groin, where Its structure is muscular; and this is the ileum terminates by entering the cæcum. necessary in order to propel the food when The small intestine possesses three coats digested. Under the muscular coat is found similar to those of the stomach : viz. an exthe internal, or villous tunic, the arteries of ternal or peritoneal; a middle or muscular ; which pour out the gastric juice, the chief and an internal or villous tunic. The latter agent in the digestion of the food.

forms a great many transverse, loose, and The pylorus, which word is derived from floating processes, called valvulæ conniventwo Greek terms, signifying the keeper of tes; by means of which the extent of surface the gate, is a contracted ring, by which the of the villous coat is very much augmented. stomach communicates with the small intes Numerous glandular bodies are found in tine. It prevents the food from passing parts of the canal, collected into small parout of the stomach, before it has been suffi- cels, and hence called glandulæ agminatæ. ciently acted on by the gastric juice.

The food which is reduced by the action The stomach receives a portion of peri- of the stomach into an homogeneous mass, toneum as the resophagus passes the dia called chyme, enters the small intestine, phragm. There is also a process coming where it undergoes a further change, and from the liver, called the lesser omentum, or becomes chyle. It is propelled along the mesogaster. This is attached to the lesser canal by the muscular coat of the intestine, arch of the stomach. The great omentum, and the villous tunic absorbs from it the or the caul, is affixed to the greater arch of nutritious particles. It passes along 'every the stomach, and hangs from thence over the turn and winding of this long canal, continusurface of the intestines ; being interposed ally subjected to the action of the absorbing between them and the intestines. It is also vessels. The residue of the alimentary mat.

ter is sent into the large intestine, from Lypochondrium. Its size is greater in proporwhich it is expelled in the form of fæces. as the animal is younger. In the adult it is

The large intestine is a canal of about two contained within the cartilages of the ribs ; or three inches in diameter, and seven feet but in the fætus it extends to the navel, and in length. It is divided into the cæcum, fills half the belly. Its upper surface is concolon, and rectum. The cæcum is a bag vex, and in close contact with the concave situated in the right groin, and receiving the under surface of the diaphragm. Its under termination of the ileum. The latter intes or concave surface rests chiefly on the tine enters in such a manner that the pas stomach. It is divided into a right and left sage of the aliment is allowed from it into lobe, and lobulus spigelii. It has a posterior the cæcum, but prevented from returning. and thick, an anterior and thin margin. Its The part which effects this is called the colour, in the most healthy state, is of a red. valvula coli. A small process, about equal dish brown; but it often deviates from this. in size to an earthworm, is connected to Its weight, in an adult man of middling stathe crecum. It is called appendix cæci ver- ture, is about 3 pounds. It is connected to miformis, and its use is unknown.

the diaphragm by four ligaments: riz. 1. From the right groin the intestine ascends ligamentum latum, or suspensorium, which on the right side of the abdomen over the divides the right and left lobes from each kidney, under the name of colon: it turns other. The front edge of this part contains completely over the abdomen at the upper the fibrous remains of the umbilical cord part, and descends along the left side to the of the fætus, which assuming the appearance left groin ; here it makes a large turn over of a round rope, is called the round ligament. the brim of the pelvis, and enters that cavity, 2, 3. Ligamenta lateralia, or dextrum, et where it takes the name of rectum, which sinistrum. 4. Ligamentum coronarium. terminates at the anus. We distinguish in The liver is covered exteriorly by peritothe colon, the right or ascending portion; neum, and there are certain fissures and the middle or transverse arch ; the left or excavations on its surface. 1. Fossa, for the descending; and the sigmoid flexure. The gall-bladder, in the under surface of the right right and left portions of this gut are closely lobe. 2. Fissure on the anterior, thin marbound down in their situations, by two por- gin for the entrance of the umbilical vein. tions of peritoneum, called ligamenta coli. 3. Portæ, or large transverse notch, at The transverse arch has a broad process which the blood vessels enter, and from connected to it, by which it is loosely at which the hepatic duct proceeds. 4. Notch tached : this is called the mesocolon.

for the inferior vena cava, 5. Excavation The large intestines have a peritoneal, a for the bodies of the vertebræ. muscular, and a villous coat; but they have The liver is composed of a tolerably no valvulæ conniventes. The longitudinal firm and close substance, consisting of a muscular fibres are collected into three

closely united congeries of different vesbands, which being shorter than the rest of sels. These vessels are the vena portathe intestine, occasion the other coats to be

rum, the hepatic artery, the hepatic veins, gathered up in folds between them, and and the biliary ducts. The former vessel thereby give the intestine a sacculated ap- carries to the liver the blood which has cirpearance.

culated through the different abdominal The residue of the alimentary matter, viscera. It ramifies in the liver like an arwhich the large intestine receives from the tery, and the secretion of the bile is supsmall, is converted in the former canal into posed to take place from the blood, which a substance of peculiar odour, colour, and it conveys to the liver. The blood of this consistence, called fæces; in which form it vein, as well as that brought by the hepatic is expelled from the body.

artery, for the nourishment of the liver, is

returned by the large hepatic veins to the Purts subservient to the functions of the

inferior vena cava. The small branches of alimentary canal, and contained in the

the hepatic duct which conveys the secreted cavily of the abdomen.

bile from the liver, appear like small yellow The liver is the largest glandular mass in pores, when a section of the liver is made, the body, and is placed towards the right and hence they are called pori biliarii. side of the epigastric region. Its thickest The mesogaster or little omentum, is at. portion fills the right hypochondrium; a tached to the portæ of the liver. The vena thinner part of the gland extends across the portarum, the biliary ducts, the hepatic middle of the epigastric region to the left artery, and the hepatic plexus of nerves,

« PreviousContinue »