CHAPTER I. PRACTICAL POINTS IN ANATOMY AND PIYSIOLOGY. (Part 4)

Such an injury is often only noticeable- through a constant discharge of rectal mucus, and an occasional involuntary escape of fluid faeces when the patient is suffering from diarrhea. This leads naturally to a consideration of the third or superior sphincter muscle,' whose existence has been 1 Gosselin: ‘ Rétrécissements Syphilitiques du Rectum,” Arch. Gén. de Mé 1854, p. 668. . Henle: ‘‘ Handb, der systemat. Anat. des Menschen,” 1873, Bd. ii. Hyril: “ Handb, der topogr. Anat.,” Wien, 1857, Bd. ii., pp. 108, 109. Sappey : ‘‘Traité d’Anat. Descriptive,” Paris, 1874, t. Chadwick : ‘Trans, of the Am, Gynivcol, Soc.,” ti., 1877. 26 DISEASES OF THE RECTUM AND ANUS. supposed to account for such control of the evacuations as exists in this condition. Tt is now about half a century since Nélaton first described the third sphincter muscle, and, in spite of all that has been written concerning it since that time, it is only a few years since Van Buren' characterized it as an organ to which ana- tomy and physiology had been equally unsuccessful in assign- ing either certainty of location or certainty of function. For the original description of the muscle by Nélaton we are in- debted to Velpeau, who writes that he has verified the existence of a sort of sphincter of the rectum, lately discovered by Néla- ton, and goes on to say that itis a muscular ring situated about four inches above the anus, just in the place where retractions of the rectum are most often found. If, after turning the rec- tum so that its mucous surface is external, it is moderately dis- tended by insufflation, the muscle will be seen to be made up of fibres collected into bundles. Its breadth is from six to seven lines in front, and about an inch behind. Its thickness, on the contrary, is much greater in front, where the fibres appear to be collected in the angle which corresponds to the union of the first and second curves of the rectum, while behind they are scat- tered over its convexity. After.thus adopting the description of Nélaton, Velpeau* brings out one other anatomical point—the attachment of the muscle posteriorly to the front of the sacrum. The functions ascribed to the muscle by Nélaton were those of keeping the rectum empty until a short time before the act of defecation ; separating the feecal mass and preventing its re- gurgitation during defecation ; and of opposing the continuous and involuntary escape of feces after the destruction of the lower sphincters. Hyrtl refers to this description, and himself describes the muscle as being six or seven lines in breadth anteriorly and an inch posteriorly, but does not always find it present. He also in Pétrequin : ‘Traité d’Anat. Topogr. Med.-Chirurg.,” ete., 2me éd., Paris, 1857, p. 414 Houston : ‘‘ Dublin Hospital Reports,” v., 1830. O'Beirne: ‘ New Views of the Process of Defecation,” etc., Dublin, 1833. Bushe: “Treatise on the Malformations, Injuries, and Diseases of the Rectura and Anus,” New York, 1837. Kohilrausch : «Anat. u, Physiol. der Becker Rosswinkler : Wien, med. Woch., 1852, p. 4: Foster: ‘Text Book of Physiology,” Philadelphia, 1880, p. 887. 1“ On Phantom Stricture,” etc., Am. Jour, of the Med. Sci., October, 1879. 2 Velpean: “ Traité d’Anat. Chirurg.,” 8me ¢d., 1837, Introduction, p. 39. rgane,” Leipzig, 1854. POINTS IN ANATOMY AND PHYSIOLOGY, 27 one case demonstrated the attachment to the sacrum. Sappey admits its frequent existence, and locates it at the level of the base of the prostate, in the middle portion of the rectum, six, seven, eight, or sometimes nine centimetres from the anu It never completely surrounds the rectum, but only one-half or two-thirds of its circumference ; and it appears to him to be caused by a grouping of the circular muscular fibres. some being gathered from below upward, and others from above downward, to the same point. Its breadth is one centimetre and its thickness two or three millimetres. Situated sometimes in front, sometimes behind, and again laterally or antero-late- rally, it is constant in nothing except its direction perpendicular to the axis of the bowel. In place of one, he has sometimes found two bands at opposite points and different levels, and in one specimen which he has preserved there were three. Henle adopts Sappey’s description in the main. Pétrequin found the muscle irregularly oblique, less marked in the front wall than in the back, and consisting of a collection of weak bands of fibres. Chadwick asserts that no distinct muscle exists, but describes in place of it two agglomerations of the circular mus- cular fibres, one on the anterior and one on the posterior wall, corresponding to two semicircular constrictions, which may be felt by digital examination, and whose effect is to give the rec- tum its sigmoid curve. The third sphincter muscle and the valves of mucous mem- brane in the rectum are not, as might be supposed, one and the same thing, though it is true that they have become almost hopelessly, confounded in surgical and anatomical literature, and are often spoken of as identical. As far as possible, we shall try to consider them separately, without doing violence to the text of the authorities. The valves of the rectum (we use the word simply as expressing the folds of mucous membrane) were first described by Houston at about the same time that Nélaton described the superior sphincter; and it is worth remembering that the two authors were writing about two entirely different things, and two things which stood in no nec- essary relation to each other, so far as we may judge from their descriptions. Houston's method of preparation was by filling and distending the gut with spirit before its removal from the body, and then laying it open longitudinally. He states that the folds disappear if the bowel is first removed from its natural position and then distended, but that they may be seen in the natural condition of the parts soon after death, before the tonic 28 DISEASES OF THE RECTUM AND AN contraction has disappeared; and that they are then found to overlap each other so effectually as to require considerable manceuvring in order to pass a bougie or the finger along the bowel. It is also remarked that this is just the arrangement. necessary to prevent the feeces from urging their way toward the anus, where their presence would excite a constant sensa- tion demanding their discharge. According to this first and clearest of all the descriptions— for the whole article is written with a force and clearness of style which have perhaps had an undue weight in disarming criticism as to the facts—the valves exist in all persons, but vary much in different individuals as to location and number. Three is the average number, though sometimes four, and again only two, are well marked. The largest and most constant is. about three inches from the anus, opposite the base of the blad- der ; the next most constant is at the upper end of the rectum ; the third is about midway between these ; and the fourth, or the one most rarely present, is attached to the side of the gut about an inch above the anus. The first one generally projects from the right wall; the one next above, from the left ; the uppermost, from the right; and the one nearest the anus, when present, from the left and posterior wall; the arrangement being such, in spite of variations, as to form a spiral tract down the gut. The folds are described as semilunar in form, with the convex border attached to the side of the bowel, and occupying from one-third to one-half of its circumference. The surfaces are sometimes horizontal, but more often oblique, with the sharp, concave, floating margin generally directed a little upward. In breadth they vary from one-half to three-quarters of an inch or more in the distended state of the gut; and they are said to be composed of a duplicature of mucous membrane enclosing some: cellular tissue and a few of the circular muscular fibres. The palpably weak points in Houston’s article were very soon pointed out by O’Beirne, in a work of marked and almost amus- ing originality. The views were indeed ‘‘new,’” but they are to-day accepted in many points by those whose judgment is worthy of the most confidence in these matters. O’Beirne seems. rather to regret that he is unable to accept Houston's statements as to an anatomical condition which would account so fully and so easily for the physiological emptiness of the rectum and ful- ness of the sigmoid flexure on which his own views depend ; but nevertheless he sets himself to the task of demolishing them with great vigor and considerable success. Although he believes POINTS IN ANATOMY AND PHYSIOLOG 29 the rectum to be normally empty, except just at the time of de- fecation, he believes that condition to depend upon the anatomi- cal arrangement of the sigmoid flexure, joined with the narrow- ing of the upper end of the rectum, which is entirely independent of any folds of mucous membrane. He not only denies the existence of any such folds, but states flatly that Houston is al- together incorrect in his statement that Cloquet or any other anatomist before his time makes even the slightest allusion to them.' He believes the folds to have been produced by the method of making the preparations—distending and hardening all the parts with spirit before making the incision—and asserts that this method is anything but natural, and nothing more or Jess than an attempt to exhibit natural appearances by placing the parts in an unnatural situation—such a situation, indeed. as is not known to be necessary for the exhibition of the valvule conniventes or any other valves of the body. He meets the statement, that by the ordinary procedure of distending the rec- tum after removal from the body the valves are made to disap- pear, by the question, why, if such valves really exist, and if muscular fibres enter into their structure. they should not be discoverable at any time after death, or in any state of the in- testine—a question very difficult of solution. Four years later the voice of a New York surgeon was raised against these folds, and in almost the same language as O'Beirne’s, though from an entirely independent standpoint. Bushe declares that he has never, in the living body, been able to detect any valve of such firmness, and capable of exerting any such influence upon the descent of the feeces, as Houston describes, though he has frequently met with accidental folds produced by the partial contraction of the bowel ; and the proof that they are accidental is that, in the same subject. he has on different days found them to occupy different situations, but they were always unresisting and easily displaced by the ‘Regarding this question of fact, it may be well to quote Cloquet’s description from Bushe, op cit., p. 60: “The inner surface of the rectur in its upper half, but in the lower there are observed some parallel longitudinal wrin- kles, which are thicker near the anus, and are ble in length. ‘These wrinkles, whose number varies from four to ten or twelve, aud which are called the columns of the rectum, are formed by the mucous membrane and the la: cellular tissue. Between these columns there are almost always to be found mem- Dranous semilunar folds, more or less numerous, oblique or transverse, of which the floating edge is directed from below upward toward the cavity of the int ‘These folds form a kind of lacuns, of which the bottom is narrow downward.” It scems evident that the sinuses of Morgagni are here refe1 s commonly smooth er of the subjacent 30 DISEASES OF THE RECTUM AND ANUS. extremity of the finger. He points out that, by the method of hardening the rectum after distending it with spirit, these acci- dental folds are rendered permanent by the induration resulting from the action of the alcohol; and that, by the method of inflation and drying, the projections resembling valves are produced by the angles formed by the setting of the intestine during the process of desiccation. Kohlrausch describes and figures one important fold, the plica. transversalis recti. which he locates at the same point as Hous- ton’s most constant one, projecting well into the lumen of the bowel from the right side. It forms rather more than a semi- circle, and runs further on the anterior than on the posterior wall. Here also we meet the direct statement that this fold is now known as the sphincter ani tertius, though Kohlrausch does not consider such a title justified by the anatomical condi- tion, inasmuch as the circular muscular fibres do not enter into its texture, and are not more developed here than elsewhere. For, though both these things may happen, as a rule neither is the case. Sappey says he has found in the empty state various folds of the mucous membrane, but that these have no determinate direc- tion, and are generally only slightly marked. Three times only, in thirty recta which he examined, has he met with anything which at all answered to Kohlrausc! plica transversalis or to Houston's chief valve. There is nothing to prove that they per- sist when the rectum is full; on the contrary, it is probable that they are effaced by the simple fact of distention of the latter, at least in great part. The name of valve is not, therefore, appli- cable to them, and, admitting even that it might be used by one of those abuses of language so frequent in anatomy, Houston would still incur the discredit of having presented as normal a fact which is only observed very exceptionally. Henle divides the valves into two varieties, the temporary and the permanent. Of the former he de: pes several, which may be present or absent in the same individual at different times or in different states of the bowel. Of the permanent variety there is only one—the plica transversalis—and this one is only present in a minority of subjects. Hyrtl describes two folds, both constant: one on the right wall lower down, and one on the opposite side. Rosswinkler also describes two folds, but locates them on opposite sides to those of Hyrtl.