CHAPTER I. PRACTICAL POINTS IN ANATOMY AND PIYSIOLOGY. (Part 3)

tween this fascia and the peritoneum is the superior pelvi-rectal space of Richet. (See Fig. 41.) Its inferior surface is separated from the obturator internus muscle by the obturator fascia, and beneath this is the ischio-rectal fo: The posterior part of the muscle is in relation with the gluteus maximus. The actions of this muscle are various. First, it acts as a support to the pelvic organs, and antagonizes the diaphragm and abdominal muscles when they act upon the abdominal con- tents. By enclosing the neck of the bladder the mus upon it also, and in the act of defecation, when the muscle is contracted to open the anus, the neck of the bladder is pressed upon and the urethra closed. In this way is explained the well- known difficulty of passing urine and feces at the same time, By enclosing the bladder, vesiculee seminales, prostate, and rec- 2 ES OF THE RECTUM AND AN tum in its grasp, the muscle produces a sympathy among these parts which will often be found very distressing in diseases of the rectum or after operations for their relief—such as impos- sibility of micturition, erections, and lancinating pain due to spasmodic action of the muscle. It will often happen that after a complete paralysis by free division of both sphincter muscles in an operation upon the rectum, the patient will still complain of a sharp, spasmodic pain at intervals—just such a pain as is caused by spasmodic contractions of the sphincter. In such cases it is the levator ani which is at fault. The muscle also aids the longitudinal fibres of the rectum in their opposition to the dragging of the feeces; and the anal fibres also draw the rectum upward and forward, and compress it on the sides, and thus aid in the expulsion of its contents. The voluntary sphincteric action of this muscle in connec- tion with the ischio-coccygeus is of considerable power. It is brought to bear at a point about an inch anda half above the anus (above that of the involuntary internal sphincter), and no doubt in a measure accounts for the partial control over the passage of fzeces often seen after destruction of both the internal and external sphincters. The muscle receives a filament from the fourth sacral nerve on its pelvic surface, and another from the internal pudic. Transversus Perincei.—This also has an action in defecation. Its fibres do not always blend with those of the opposite side in the median raphé, but the two muscles are sometimes continu- ous, traversing the anterior extremity of the external sphincter. In such a case the two muscles form a continuous half-ring, the concavity of which is directed backward and embraces the an- terior part of the rectum, assisting powerfully in defecation by pressing the anterior against the posterior wall of the bowel in conjunction with the external sphincter (Cruveilhier Arteries.—The rectum is supplied with blood from five arte- ries, one single and two pairing. The superior hemorrhoidal i of the superior mesenteric. It is the direct continuation of the parent trunk, passing into the pelvis behind the rectum in the fold of the meso-rectum, and dividing into two branches which extend, one on each side of the bowel, to its lower end. About five inches from the anus these subdivide into smaller branches, about seven in number, which pierce the muscular coat about two inches lower down. They then descend between the mu- cous and muscular layers at regular intervals to the end of the ingle and is a direct branch POINTS IN ANATOMY AND PHYSIOLOGY, 19 bowel, where they communicate in loops opposite the internal sphincter, and anastomose with the terminal filaments of the middle and inferior hemorrhoidal arteries. The middle heemorrhoidal arteries—one on each side—are not constant in their origin, sometimes coming from the hypo- gastric or the inferior vesical, and sometimes from other source: The inferior heemorrhoidal arteries—also pairir are usu- ally given off from the internal pudic near the point where it crosses the tuber ischii. They cross through the fat of the ischio-rectal fossa, and are distributed with the middle heemor- rhoidal to the lowest part of the rectum, and to the anus and adjacent skin, Veins.—There are three sets of rectal veins, as there are three sets of arteries, the superior, middle, and inferior ; and these are so arranged as to form two distinct venous ems— the one, rectal, and returning its blood to the vena por ze: the other, anal, returning its blood through the internal iliac. The first, or rectal circulation, is made up of the superior hemor- rhoidal vein: the second, or anal, is made up of the middle and. inferior hemorrhoidal veins, the middle receiving its blood from the anus, and the inferior from the adjacent integument. The middle heemorrhoidal ascends obliquely into the ischio-rectal fossa ; the inferior starts horizontally from the skin of the anus and empties into the internal pudic. The middle hemorrhoidal is formed from two venous trunks. one on the anterior, the other on the posterior aspect of the re tum, which, by anastomosing with the corresponding branches from the opposite side, surround the sphincter in a venous cirel From this circle spring the collateral branches, which by their successive division and anastomoses form a true venous plexus. The inferior hemorrhoidal vein also has a plexiform arrange- ment at its origin, but its branches are situated between the skin and the inferior border of the external sphincter. The rectal pouch is not, therefore, supplied with blood from the external hemorrhoidal veins, but only the anus and the region of the sphincters. When, on the other hand, the venous circulation of the rec- tum proper is injected from the inferior mesenteric vein, three or four large venous trunks may be seen on the external surface of the rectum ascending on the sides and posteriorly (Ff and10). These veins make their appearance suddenly by five ov six branches, which perforate the wall of the bowel about three inches from the margin of the anus. If the rectwm be.opened 3.9 20 ‘S OF THE RECT longitudinally, and the mucous membrane dissected up to a suf- ficient height (about four inches), it will be seen that these five or six large veins, already visible on the outside of the bowel, come from within, and that they have already pursued quite a long course under the mucous membrane. They are formed by collateral branches, and especially by about a dozen primitive branches, which originate about half an inch above the anus and ascend in parallel and flexuous lines for several centime- : S. E,. external sphine- hemorrhoidal vein; Fic. 9.—Rectal Veins seen from without (Duret).! ter: P., skin at margin of anus dissected up aud tur 3 V. HL M,, middle hemorrhoidal vein; V. H. E., external hemorrhoidal vei tres to unite into common trunks. Each of these little ascend- ing branches has its origin in a minute pool of blood, the size of which varies in the normal state from that of a grain of wheat to that of a small pea. 1“ Recherches sur la Pathogénie des Hémorrhoides,” Arch, Gén. de Méd., Decem- ber, 1879. POINTS IN ANATOMY AND PHYSIOLOGY. 21 These little sacs are arranged in a circular form around the extremity of the rectum. If carefully dissected they may be seen to be connected with the little veins before mentioned, and also with another little vein which perforates the internal sphincter near its lower edge. and empties into one of the rudi- mentary branches of the external hemorrhoidal plexus. Many of these little communicating branches between the external and internal hemorrhoidal systems pass through the substance P. Fi, 10.—Rectal Veins seen from within (Duret), M.q., mucous membrane dissected up and cut away below; M. cl., muscular tunie; Sp. L, internal sphineter; Sp. K., external sphincter; P., skin; H. L., internal hemorrhoidal vein; H. M., middle hamorrhoidal vein; V. H. E., external hemorrhoidal vein, of the external sphincter. It results from this that when the external sphincter is contracted the anastomosis between the two systems is prevented. Verneuil has laid stress upon the fact that where the in- ternal or superior hemorrhoidal veins perforate the rectal wall from within outward, they pass through “muscular. button- 22 DISEASES OF THE RECTUM AND ANUS. holes” surrounded by no fibrous tissue, and having, therefore, the power of contracting round the vein, closing its calibre, and preventing the return of blood to the liver. In this anatomical arrangement he believes he has found the active cause of in- ternal hemorrhoids. The disposition of the rectal veins into two distinct systems, the one internal and the other external, is fully in conformity with our knowledge of the development of the rectum and anus. The rectal cul-de-sac is at first situated at some distance from the perineum, and as it descends it carries with it its own proper vascular supply. The anal depression is of necessity provided with an independent set of veins, and when the rec- tum and anus are finally united into one canal the two venous systems also unite. The internal hemorrhoidal veins also communicate freely with other branches of the internal iliac around the trigone of the bladder by means of minute branches, from one-half to one mum. in diameter, which pass through the prostate and vesicule seminales. Nerves.—The nerves of the rectum and anus are derived from both the cerebro-spinal and sympathetic systems. The former are branches from the sacral plexus, the latter from the mesenteric and hypogastric plexuses. The spinal nerves are derived from the third and fourth sacral, which supply visceral branches to all the pelvic organs, anastomosing with branches from the sympathetic. The muscular branches from the same nerves have already been spoken of in connection with the indi- vidual muscles. The fifth sacral nerve also sends a small twig to the coccygeus. The posterior branch of the superficial peri- neal nerve from the internal pudic supplies the skin in front of the anus, while the anterior branch gives several small fila- ments to the levator ani. The inferior hemorrhoidal branch from the pudic supplies the lower end of the rectum. the external sphincter, and the skin of the anus. This nerve may come direct from the sacral plexus through the lesser sacro-sciatic notch. The posterior branches of the sacral nerves also supply the skin over the coceyx and around the anus. According to a brief contribution of W. Krause,' the nerves end in the mucous membrane of the anus, in club-shaped bulbs, about 0.05 mm. in diameter, which lie under the bases of papillee. 1 Esmarch, op. cit.. p. 10. POINTS IN ANATOMY AND PHYSIOLOGY. 23 The tonic contraction of the external sphincter muscles is, in part at least, due to the influence of a nerve centre located in the lumbar region of the spinal cord.’ If the nerve connection of the sphincter with the spinal cord be severed, relaxation of the muscle takes place. The fact that division of the cord in the dorsal region does not affect the sphincter, except tempo- rarily by shock or depression, proves that this centre is not located above the lumbar region. This nerve centre is subject to various influences ; and the sphincter may cither be relaxed, or its tonic contraction increased, by local stimulation, or by the influence of the will or emotions. Though the dependence of the sphincter for its tonic con- traction upon the lumbar nerve centre seems so great. still it is not absolute. In the case of aman in whom the sacral nerves were entirely paralyzed by an injury, and in whom, therefore, there was no nerve connection with the lumbar centre except perhaps through the sympathetic, Gower’ observed the main- tenance of a certain amount of tonic contraction, which could be inhibited and relaxation produced by stimulation of the mu- cous membrane of the rectum and anus. From this it would appear that the tonic contraction of the sphincter, as is known to be the case in the arterial system, is habitually dependent on a spinal centre, but may, nevertheless, exist without the action of that centre. The paralysis of the muscle which follows brain lesions is probably due merely to inhibition of the spinal centre, and not to the injury of any centre located in the cerebrum.’ The distribution of the spinal nerves serves to explain many of the reflex and so-called anomalous symptoms of pain which are encountered in diseases of the rectum and anus. Brodie‘ 1 Masius. Bull. de Acad. Royal de Belgique, xxiv. (1867), p. 312 (Poster’s “Physiology,” p. 337). ? Proc. Roy. Soc. (1877), p. 77. * Poster's “ Physiology,” p. 388. Philadelphia, 1880. +A lady consulted me, says Mr. Brodie, concerning a pain to which she had been for some time subject, beginning in the left ankle and extending along the in- step toward the little toe, and also into the sole of the foot. The pain was described as being very severe. It was unattended by swelling or redness of the skin, but the foot was tender. She labored also under internal piles, which protruded externally when she was at the water closet, at the same time that she lost from them some- times a larger and sometimes a smaller quantity of blood. Ona more particular in- quiry [learned that she was free from pain in the foot in the morning ; that the p attacked her as soon as the first evacuation of the bowels had oceasioned a protrusion of the piles; that it was especially induced by an evacuation of hard frees ; and that, if she passed a day without any evacuation at all, the pain in the foot never troubled her. Having taken all these facts into consideration, I prescribed for her 24 DISEASES OF THE RECTUM AND ANUS. relates an instructive case of pain in the foot over the distribu- tion of the sciatic which was cured by curing prolapsing he- morrhoids—the irritation being primarily at the termination of the internal pudic, and conveyed thence to the sacral plexus, to be carried to the termination of the great sciatic; and I have the notes of an exactly analogous one in aman. In the same way a fissure of the anus or other disease of the rectum may cause pain in the lumbar and iliac regions, pain, loss of sensa- tion, and cramps in the legs, and symptoms of bladder and ure- thral disease, besides more general nervous phenomena (see Fig. 11). The chief nerve supply of the rectum is at the lower portion and around the anus—the middle and upper portions possessing very little sensibility ; so little, in fact, that the gravest diseases, such as cancer or ulceration, may exist and not manifest them- Fic. 11.—Diagrammatie View of the Nerves of the Anus (Hilton). a, Uleer on sphincter; b, the filaments of two nerves are exposed on the ulcer, the one a sensory and the other motor, both attached to the spinal marrow, thus constituting an excito-motory apparatus; ¢, levator ani: d, transversus perineei, selves by pain. This also explains how large masses of feeces may accumulate in the rectal pouch without causing suffering. Puncturing the bladder through the rectum is not a painful operation, and applications of strong acids to the mucous mem- brane will cause little suffering if the skin be properly pro- tected. Exactly the opposite condition obtains at the anus, the extreme sensibility of which is well known. the daily use of a lavement of cold water ; that she should take the Ward’s paste (confectio piperis composita) three times daily, and some lenitive electuary at bed- time. After having persevered in this plan for a space of six weeks, she called on me again, The piles had now ceased to bleed, and in other respects gave her scarcely any inconvenience. ‘The pain in the foot had entirely left her. She observed that, in proportion as the symptoms produced by the piles had abated, the pain in the foot had abated also.—Medical Gazette, vol. v. POINTS IN ANATOMY AND PHYSIOLOGY, 25 The pelvic plexuses of the sympathetic are placed one on either side of the rectum and vagina. Each is composed of pro- longations from the hypogastric plexus above, united with branches from the sacral ganglia. The spinal branches to the sympathetic are mostly from the third and fourth sacral nerves. From the back part of the plexus thus formed are given off the inferior hemorrhoidal nerves, which join with the superior heemorrhoidal from the inferior mesenteric artery and perforate the rectal wall. Lymphatics.—The lymphatic vessels of the rectum are ar- ranged like those of the intestine generally, in two layers ; one beneath the peritoneum and one between the mucous and mus- cular coats. Immediately after leaving the bowel some of the vessels pass through small adjacent glands, and all finally enter the glands in the hollow of the sacrum, or those higher up in the loin. But just as there is an internal and external system of veins, one proper to the rectum, the other to the anus, so is there another lymphatic system, which comes from the integument around the anus and passes to the glands in the groin; and these two sets of vessels freely communicate with each other. Aknowledge of this fact is of importance in the diagnosis of caneer of the rectum ; and the glands which are deep in the pel- vis along the sacrum should always be felt for, as well as those located in the groin. Defecation.—A study of the anatomy of the rectum would not be complete without some reference to its physiological functions.. We shall, therefore, in this place consider the func- tion of defecation. In regard to defecation the question at once arises, how, after destruction of the lower end of the rectum, or paralysis of the sphincters, there still remains a certain amount of control over the evacuations?