Paper - Development and transition of the testis, normal and abnormal 4
|Embryology - 13 Apr 2021 Expand to Translate|
|Google Translate - select your language from the list shown below (this will open a new external page)|
العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt These external translations are automated and may not be accurate. (More? About Translations)
Lockwood CB. Development and transition of the testis, normal and abnormal. (1888) J Anat. 22(4):505-41. PMID 17231761
|Historic Disclaimer - information about historic embryology pages|
|Embryology History | Historic Embryology Papers)|
The Development and Transition of the Testis, Normal and Abnormal
By C. B. Lockwood, F.R.C.S., Hunterian Professor of Comparative Anatomy and Physiology, Royal College of Surgeons of England. (Puate II.)
(Continued from vol, xxi. p. 664.)
Lecture III - Continued
Ir the observations recorded in the earlier part (p. 464) of this Lecture be correct, the testicle has attained its position upon the brim of the pelvis, and almost in contact with the hypogastric arteries and the abdominal walls, by a gradual process of development and growth. But already, at the third month, preparations are being made for the active transition of the gland through the abdominal wall, and its final deposition in the scrotum. Amongst these preparations are comprised the further development of the mesorchium and of its ascending and descending processes, namely, the plica vascularis and the plica gubernatrix, the development of the gubernaculum itself, the development of the inguinal canal, and, finally, the development of the scrotum.
It is convenient to refer briefly to such of these as can be seen with the naked eye, and then proceed with those which require to be studied by means of histological sections.
The Mesorchium, Plica Gubernatria, and Plica Vascularis
The mesorchium has frequently been mentioned before, and is the fold of peritoneum which unites the mesonephros, and afterwards the epididymis, to the back of the abdomen; the word is not, perhaps, quite free from ambiguity, for the mesentery belongs more especially to the mesonephros, but as the name is established by custom, it is desirable to continue its use. At the third month the mesorchium is but a slender support, and is prolonged upwards from the epididymis in a small triangular fold; and, as this subsequently contains the spermatic vessels, I have, in a paper on “ Encysted and Infantile Hernia,” ! ventured to call it the plica vascularis. Without doubt the plica vascularis is the same as the fold which at an early age unites the upper end of the Wolffian body to the diaphragm, and is called by Kolliker? the diaphragmatic ligament of the mesonephros (Zwerchfellsband der Urniere). However, in the later stages these relations of this fold are quite subordinate ; whilst, as will be seen, its relations to the spermatic vessels are of practical and pathological importance. The mesorchium is shown in the accompanying drawing, made from a human embryo of the third month, and in this specimen the testicle and kidney are a little way apart, the separation being caused, I believe, by the growth of the lumbar spine and pelvis, including the sacrum in the pelvis. The plica vascularis does not reach quite as far as the kidney, but is, nevertheless, an obvious feature (Pl. XVII. fig. 48). The lower part of the mesorchium is, on either side, continued along the night and left genital strings, to become continuous with a cord which passes down to the outer side of the hypogastric arteries, and ends in the abdominal wall. This cord is an early stage of the gubernaculum testis, and the downward prolongation of the mesorchium® is the plica gubernatrix. It is hardly requisite, perhaps, to trace minutely the gradual growth of the mesorchium. It does not, perhaps, develop luxuriantly in every foetus, but at about the end of the seventh month it usually has the appearance seen in the accompanying sketch (fig. 49). The base of the mesorchium was loosely fastened along the psoas muscle, and its free edge ended upon the epididymis and testicle; its lower fold contains the gubernaculum, and the upper the spermatic vessels. However, at this age (seventh month) the chief interest of the upper process centres in its relation, on the right side, to the cecum, vermiform appendix, ilium, and mesentery, to which it is now (towards the end of intrauterine life) adherent; and later it will be seen that this may have an important bearing upon the pathology of congenital ccecocele; on the left side it passes upwards to the sigmoid flexure. The plica gubernatrix, moreover, disappears below in a peritoneal pouch, which is the beginning of the processus vaginalis. The formation of this protrusion may be considered after the development of the scrotum and inguinal canal.
- 1 “The Morbid Anatomy and Pathology of Encysted and Infantile Hernia,” by C. B. Lockwood, Med. Chir. Trans., vol. lxix., 1886.
- 2 Kolliker, Eniwicklungsgeschichte, p. 959.
- 3 The mesorchium is sometimes called ‘‘ Seiler’s fold.”
Fig. 49 — Drawing made from a seven or eight months’ foetus to show the fold (plica vascularis) which connects the testis with the cecum. T, testicles ; E, epididymis; P, psoas; V, vas deferens; G, plica gubernatrix, disappearing into processus vaginalis; P.V, plica vascularis ; C, cecum ; S,"spermatic artery ; I, ilium.
The Development of the Scrotum and Inguinal Canal, includung the Ascending and Descending Cremaster
It is proposed as far as possible to pursue this branch of the subject by means of histological sections. As far as can be ascertained, most of our knowledge of it has been learnt by dissection ;? yet, although a great deal of information has been gained in this manner, nevertheless, the embryonic tissues are so delicate and hard to manipulate that there seems to be still room for further inquiry. This refers more particularly to the histology of the earlier stages, and I now propose to describe them as briefly as possible, using for the purpose human embryos, which may be supposed to have attained the seventh, tenth, twelfth, and twentieth weeks of intrauterine life.
- 1 I am indebted to the Council of the Royal Medico-Chirurgical Society for permission to use this and another block.
- 2 F. Bramann, in his ‘‘ Beitrag zur Lehre von dem Descensus testiculorum und dem Gubernaculum Hunteri des Menschen,” Archiv fur Anat. und Entwick., 1884, p. 310 e¢ seg., gives an exhaustive account of the literature of the subject, and his investigations will be mentioned again.
At the seventh week the structure of the abdominal wall is very rudimentary, and it contains but a trace of muscle in its substance. Its exterior is covered with a layer of epiblast, whilst it is lined within by a clearly defined but tenuous membrane, which is the beginning of the peritoneum. Where the peritoneum lines the front abdominal wall there is no trace of subperitoneal areolar tissue, but towards the back and lower part of the abdomen that tissue is abundant, even at this early age. The main bulk of the abdominal wall is composed of ordinary mesoblastic tissue of considerable density, but towards the middle line a quantity of fine deeply stained fibres betoken the advent of the rectus abdominis. The appearances in this embryo seem to indicate that, so far as concerns the muscles of the trunk, the degree of their development is determined by their size more than by other considerations; and, in consequence, such muscles as the gluteus maximus, erector spine, and ilio-psoas are the furthest advanced. In this embryo, also, the pubic cartilages were still some distance apart, and the mesoblast of the abdominal wall continued over their surface into the perineum, making a decided bulge on either side below the pubes, in the situation of the future scrotum or labia majora, as the case may be; for it has been repeatedly said that the genital mass of this embryo is in the indifferent stage. The scrotal mesoblast is exactly the same as that which forms the abdominal wall, with the exception that it cannot be said with any degree of confidence that there is any indication of the conversion of any part of it into muscle.
Before leaving this embryo, I may mention that the bladder and hypogastric arteries are of some size, and are closely related to the lower third of the wall of the abdomen, behind the developing rectus abdominis; their width, taken together, is considerable, and they make the middle part of the lower front wall of the abdomen look very solid and impervious.
In the human embryo of the tenth week of intrauterine life (fig. 40, Lect. II.) the development of the abdominal walls has made further progress. Not only the rectus abdominis, but also the external oblique and transversalis, are clearly marked. The fibres of the various muscles are imbedded m embryonic connective tissue, which 1s most abundant beneath the cutaneous surface and almost absent where the peritoneum limes the transversalis and rectus muscles. The sections which divide the abdominal wall near the site of the future internal abdominal ring show that preparations have commenced which may be supposed to be capable of facilitating the transition of the testicle into the scrotum. Before proceeding to detail them, it may be desirable to indicate the point at which they are seen. As regards the cartilaginous skeleton, it is situated almost vertically above the outer margin of the thyroid foramen, and consequently just internal to the head of the femur. In the next place they are immediately above the inner side of the external iliac vem, which is very large, and external to the hypogastric arteries. As in the younger embryo, these vessels, together with the bladder, occupy a large part of the lower middle part of the abdominal wall. Therefore I am about to describe the abdominal wall at the point at which the internal abdominal ring afterwards appears. The abdominal wall has the following layers:—externally, of course, a cutaneous covering, which has beneath it a thick layer of undifferentiated mesoblastic tissue; next comes a thin and deeply staining lamella which merges above in muscular fibres, and, I take it, represents the external oblique; a third muscular layer forms the next stratum, and upon its inner surface the peritoneum is closely applied, except at a point which will be mentioned directly; the last muscular layer constitutes without doubt the internal oblique and transversalis. Of these various strata, the cutaneous one may be dismissed without further comment. The subcutaneous mesoblastic tissue, as In the younger embryo, extends over the pubes and is continuous with the scrotal eminence. Towards the inner side of the iliac vein, and in the position of the internal abdominal ring, the external oblique layer makes a decided bend into the subcutaneous mesoblastic tissue and towards the scrotum. The concavity of this projection, which, I believe, is an early stage of the external spermatic fascia, is thinly lined with a layer of muscular fibres derived from the succeeding layer; these represent the beginning of the descending portion of the cremaster muscle, and their hollow is filled with embryonic ‘connective tissue. Presently, ascending cremasteric fibres will be mentioned, which are derived from the muscular fibres of the abdominal wall which are nearest to the peritoneum and which ascend with the gubernaculum testis.
In this embryo, moreover, the inguinal canal has begun. The muscular layer of the lower abdominal wall («e., of the internal oblique and transversalis) may be said to have below three portions, namely, the descending cremasteric fibres, the ascending cremasteric fibres, and a middle set which descend no further than the point at which the previous two are given off. In consequence, an interval is left in the situation of the inguinal canal which has the ascending and descending cremaster for its front and back boundaries, and the middle fibres for its roof. The contents of this rudimentary inguinal canal are a quantity of embryonic connective tissue, and some gubernacular fibres which will be mentioned directly.
The peritoneum has been said to be closely united to the inner surface of the transversalis muscle, and I have now to add that it has nothing which corresponds to the bulging of the external spermatic fascia and cremaster. Its surface is quite even, with the exception of a short process which runs upwards from the abdominal wall to either genital string, and which is the beginning of the plica gubernatrix. There is a leash of fibres within the plica like those of areolar tissue, and these fibres pass upwards to the genital string and to the peritoneum; below they spread out and pass beneath the edge of the muscular layer of the abdominal wall (internal oblique and transversalis), and mingle with the walls of the projection formed by the external spermatic fascia and cremaster. The muscular fibres of the abdominal wall, which are nearest the peritoneum, instead of terminating, as the others did, to form an inguinal -canal, are, as I have already said, continued into the base of the plica gubernatrix, and will be mentioned again in speaking of the structure of the gubernaculum testis.
Finally, the testicle itself lies upon the ilium, and a very little way from the front abdominal wall. The peritoneum in the neighbourhood of the testicles and of the back wall of the abdomen has beneath it an abundance of loose embryonic connective tissue.
Assuming that these observations and inferences are correct, it is clear that the scrotum, and some of its layers, is formed long before the transition of the testicle, and quite independently of that event, There is nothing new or novel in this, but it 1s interesting to record the earliest stages of the process. Carus’s theory, that the testicle, in its descent, carried down its own investments from the abdominal wall, has been so abundantly falsified that it is quite unnecessary to argue that the foregoing is also antagonistic to the views of that authority.! This is a convenient point to mention that the hypogastric arteries seem to have an influence in determining the point in the abdominal wall at which the processus vaginalis begins to appear. It has been stated in an earlier part of this lecture that those vessels, together with the bladder, render the lower median part of the abdominal wall exceedingly thick and impervious; whilst the lower and external part is comparatively weak and unprotected. From this it follows that after the testicle and vas deferens have passed into the scrotum the ostium of the processus has the hypogastric artery upon its inner side, and it is only after that vessel has dwindled that the epigastric artery takes its place, and becomes the inner boundary of the ostium. Moreover, at first the vas deferens in its course to the migrated testicle turns round the hypogastric artery, and receives a small branch from it—the deferential artery.
The next embryo, that of the twelfth week, was, of course, much larger and better developed than that which has just been described. It was cut into a series of transverse sections, which confirmed the inferences drawn from the previous embryo, which, it may be remembered, was cut longitudinally. The testicle of this twelve-weeks’ embryo has already been figured (fig. 33, Lect. IT.), and lay upon the brim of the pelvis and very close to the abdominal wall and hypogastric arteries. The genital strings, right and left, were united to the lower part of the abdominal wall by the plica gubernatrix. This fold was narrower at either end than in its middle part, where it bulged somewhat. Its substance consisted of round and spindle-shaped cells; the latter had a decided likeness to unstriped-muscle cells, and were continued into the substance of the abdominal wall, in the situation of the inguinal canal. Moreover, the muscular fibres, which have been called the ascending cremaster, entered the base of the plica gubernatrix, and were, without question, continued upwards beneath the peritoneum, which formed the plica, as far as the genital string, or, as 1t might now be called, the vas deferens. At the point at which the plica gubernatrix was continuous with the peritoneum of the abdominal wall there was no irregularity or trace of the processus vaginalis. Both the external spermatic fascia and the descending cremaster bulge towards the scrotum, which consisted of embryonic connective tissue, whose stellate cells were very clear and unmistakable, and without any admixture of muscular fibres except those which have just been mentioned. The two halves of the scrotum had almost united, although in the perinzum there was still a wide opening beween the urethra and the exterior.
- 1 Sappey, Zraité d’ Anatomie Descriptive, vol. iv. p. 581, 1874, adduces several cogent reasons against Carus’s theory.
The main difference, therefore, between this embryo of the twelfth week and that of the tenth, assuming that their ages have been rightly calculated, seems to consist in a greater development of the muscular constituents of the gubernaculum testis, and of a further fusion of the halves of the scrotum.
It has been said that the testicle of this twelve weeks’ embryo was upon the brim of the pelvis and quite close to the abdominal wall, and this position, it will be perceived, is the same as that which the Wolffian body and genital mass or testicle occupied in embryos of the seventh and tenth weeks ; moreover, it may be added that, allowing for the growth of surroundings, its position in relation to the acetabular portion of the pelvis is practically the same.
The next stage, in which the development of the scrotum, and of the coverings of the testicle, and of the inguinal canal were investigated by means of histological sections, was probably the fifth month. In this case the processus vaginalis and gubernaculum testis had, as will be presently described, definitely appeared ; but, before mentioning them, the scrotum and inguinal canal may be referred to. Perhaps it is to be regretted that there is such an interval between this and the previous embryos, but as development proceeds it becomes more and more difficult to obtain a reliable series of histological sections, and practically it will be found that the hiatus is not likely to lead to erroneous conclusions.
The foetus from which the following conclusions were drawn was in all respects well formed, and had probably attained the fifth month of intrauterine life; its fingers and toes had fairly well-developed nails. Of course the sex was quite unmistakable, and the penis and scrotum were, so far as regards their nakedeye characters, clearly and definitely established. A series of longitudinal sections of the pelvic region, and of the abdomen below the umbilical cord, were prepared by the paraffin method, after the bones had been decalcified. In this, as in nearly all the other specimens, the stain used was picro-carmine.
The testicles lay in contact with the abdominal wall, just external to the hypogastric arteries, and apparently in front of the acetabular portion of the pelvis. But at this stage it is harder to determine this point, because, owing to the growth of the muscles and other tissues, the gland is separated some distance from any bony landmark. Moreover, the testicle has grown so little in comparison with its surroundings, that it has become quite subordinate.
As may have been inferred, the testicle is separated from the kidney by an interval of more than a quarter of an inch. It would be easy to imagine that this separation might be due to an actual locomotion of the testicle itself, but the foregoing observations show, I think, that the gland and its epididymis have still the same relation to the pelvis as their precursors, the Wolffian body and genital mass, had. The various parts of the pelvis, ilium, ischium, pubes, and sacrum have grown enormously, and also the lumbar spine. Indeed the latter has grown so much that the spinal medulla only reaches as far as a point which may be judged to be the junction of the sacrum with the lumbar spine.
However, in this foetus the preparations for the actual transition of the testicle through the abdominal wall have made considerable progress, and, as we shall see, the processus vaginalis and gubernaculum testis are definitely established. But before these are described, the structure of the scrotum may be mentioned.
The surface of the scrotum was covered with a layer of epithelium exceedingly like that which covers the cornea, and this likeness was heightened by the absence of papilla. In other regions the deeper layers of the epidermis were decidedly irregular, and rudimentary papille could be discerned. Beneath the epidermis there was a dense layer of spindle-shaped nucleated cells, the unstriped muscle fibre cells of the dartos. The bulk of the scrotum consisted of ordinary embryonic connective tissue, but its irregular cells looked more fibrillar than in the embryo of twelve weeks. Imbedded in this tissue was a denser layer of fibres, prolonged downwards from the external oblique muscle ; these looped towards the perineum, where they became gradually fainter, and finally disappeared. This layer, it may be assumed, was a further stage of the external spermatic fascia. The superficial part of the muscular layer of the abdominal wall also sent numerous fibres into the scrotum, where they spread out, and seemed to terminate; these are the fibres which have been called the descending cremaster. In the vicinity of the pubic cartilage the muscular fibres made smaller loops, and are attached to that part of the skeleton.
It may be mentioned that as yet the fibres of the various skeletal muscles, although well developed, had no appearance of striation ; except perhaps in the case of the gluteus maximus and other large muscles, in which it was in places faintly indicated, but of course the mode of preparation may have made the striations indistinct. The internal spermatic fascia is a covering of the testicle which has not been mentioned. But it is questionable whether the transversalis fascia, of which the tunic in question is a part, is itself definitely formed. As in the case of the younger embryos, the peritoneum is closely applied to the transversalis muscle, although there is, even in this position, a small quantity of tissue suitable for conversion into a fascial layer. However, even this can hardly be discerned in the neighbourhood of the processus vaginalis.
There is a striking difference in the amount of subperitoneal tissue at the front and back of the abdomen. As I have just said, there is hardly any in front, whilst behind it is exceedingly abundant, and loose in texture.
It is hardly necessary to point out that in almost every particular the histology of this five months’ embryo confirms and extends the conclusions drawn from those of the tenth and twelfth weeks. Nor is it necessary to add that the external spermatic fascia and the descending cremaster seem to have reached the scrotum by some process of growth and development, and not by any manner of traction.
It is so well known that a peritoneal pouch precedes the testicle into the scrotum, that without further premise, we may proceed to discuss the manner of its formation. Presently it will be seen that the processus vaginalis has attained a fair degree of development in the five months’ foetus which has just been described, and without doubt it appears a little earlier in intrauterine life. Care has been taken to point out that there was no trace of it in the series of sections made from either the ten weeks’ embryo or that of twelve. Unfortunately, I have been unsuccessful in preparing histological specimens from embryos of between the twelfth and twentieth weeks of intrauterine life. But in dissected specimens of embryos of an intermediate size and development, and which might be assumed to have reached the sixteenth week of intrauterine life, there was a dimple in the peritoneum at the lower end of the plica gubernatrix, and this doubtless was the early stage of the processus. This accords with Bramann’s! observations, but Kolliker? says the processus begins at the third month, and Weil? at the end of the second.
- 1 Ibid., p. 320.
- 2 Entwicklungsgeschichte, p. 994.
- 3 Weil, ‘‘ Ueber den descensus testiculorum,” &c., Zeitschrift fir Heilkunde, Bd. V., Prag. 1884, p. 226 et seg. See also footnote, p. 524.
Reverting to the foetus of the fifth month, I would direct attention, first of all, to the processus vaginalis at its opening into the abdomen. The first section which has been drawn (Pl. XVII. fig. 50) shows very clearly the lumen of the processus vaginalis and its relation to the abdominal wall. In front of it are fibres of the internal oblique and transversalis and of the external oblique muscles. The abdominal opening has not been divided at its widest part, and in sections a little further from the middle line the projecting lips seen in the drawing are absent, and the aperture involves not less than half the circumference of the canal. The plica gubernatrix projects from the floor of the processus and half fills its lumen; traced upwards it passes through the os tincse and unites with the epididymis, but before doing so receives muscular fibres, the ascending cremaster, from . the innermost layer of the abdominal muscles. The testicle lies quite close to the exterior of the processus vaginalis, and is at least twice the size of that aperture. If next the lumen the processus vaginalis be traced in its course through the abdominal walls it is found to diminish gradually (fig. 51), and end in the midst of the muscular fibres of the internal oblique and transversalis, The plica gubernatrix also dwindles in its downward course, and ceases to project into the lumen of the canal. From these appearances it may be inferred that at the fifth month the processus vaginalis is a funnel-shaped canal, wide above and pointed below; moreover, they do not favour the supposition that it has been produced by a force acting from within the abdomen, but rather by traction applied to its pointed extremity.
Fig. 50. —
Fig. 51. — Processus vaginalis in transverse section. T, testicle; J.A, iliac vessel ; P.G., plica gubernatrix and gubernaculum ; P.V., processus vaginalis; Jnt. O and 7, internal oblique and transversalis; 2.0, external oblique.
- 1 I am indebted to the managers of the British Medical Journal for the use of this and other blocks.
In older foetuses, such as those of the sixth, seventh, and eighth months of intrauterine life, the gradual progression of the processus vaginalis into the scrotum can be traced by dissection, and the mechanism of the process has been fully described by numerous distinguished observers. It is sufficient for the present to say that it always precedes the testicle towards the scrotum, and it must be admitted that, as it nears its completion, it ceases to possess a pointed extremity, and even becomes more eapacious towards its lower part. As we proceed arguments will be advanced to show that, after its muscular structure has become definitely established, the gubernaculum is capable of exerting a certain degree of traction upon the structures to which it is attached. The processus vaginalis is one of these structures, and the weight of evidence seems to favour the theory which attributes its production to the action of the gubernaculum. Perhaps it is unnecessary in the beginning to imagine an active contractive effort, and it may be urged that, at the time the processus vaginalis appears, the gubernaculum is structurally incapable of contraction. It 1s difficult to say at what moment tissues become capable of contraction. The heart beats before its walls show traces of conversion into muscle, and therefore the above is at least a doubtful argument. But when the phenomena of the infantile hernia and of congenital czecocele are considered, it will, I think, be evident that the gubernaculum has great capabilities of moving the peritoneum, and can also produce from it hernial sacs—sacs In every way analogous to the processus vaginalis, This question, together with an account of the relations which the processus vaginalis ultimately acquires to the testicle, the vas deferens, the spermatic vessels, and also to the gubernaculum and cremaster, may be conveniently deferred for a while.
The Transition of Sub-peritoneal Fat and Lipoma of the Spermatic Cord
It is of interest to remark that the processus vaginalis is accompanied towards the scrotum by a quantity of sub-peritoneal tissue and fat. In two full-grown fcetuses which I have examined, the fatty prolongation was very obvious, and in one caused a slight projection at the external abdominal ring. -The sub-peritoneal fat of the foetus is quite unmistakable, and disposed in small greyish lobules, quite unlike the fine granular fat of other regions. The import of this observation is that there is every reason to believe that the fat which migrates into the scrotum is the source of lipomata of the spermatic cord. Specimens of this rather common affection! which I have dissected are in the museum of St Bartholomew's Hospital,? and they show that the tumour is in intimate relation with the spermatic vessels, and therefore in the position which sub-peritoneal fat might be expected to occupy. In these cases the lobes of fat were not continuous with that inside the abdomen, but, as Mr Hutchinson shows, this circumstance has been observed in cases of the same description,
The Gubernaculum Testis
This structure has already been mentioned several times, and the first trace of it was noted in the histological sections of the human embryo of the tenth week of intrauterine life; and at the twelfth week it could easily be seen with the naked eye. Few things have given rise to so much controversy, and those who are interested in the matter will find the views of the various authorities, both ancient and modern, summarized in the memoirs of Cleland,’ Godard,t Bramann,’ in the joint memoir of Debierre and Pravaz,° and elsewhere.’
- 1 For cases of the same sort see Curling, On the Testicle, p, 556; also Path. Trans., vol. xxxvii., 1886, shown by Mr C. Stonham; also a paper by Mr J. Hutchinson, jun., p. 451 of the same volume, in which the subject is fully discussed.
- 2 Sp. 2812a.
- 3 Mechanism af Gubernaculum Testis, 1856.
- 4 M. E. Godard, ‘ Etudes sur la Menorchidie et la Cryptorchidie chez ’homme,”’ Comptes Rendus de la Soc. de Biologie, Paris, 1857, p. 315 et seq.
- 5 Bramann, Archiv fiir Anat, wnd Phys., 1884, p. 310 ef seq.
- 6 Ch. Debierre et J. Pravaz, Contribution a étude du Muscle Cremaster, du Gubernaculum Testis et de la Migration Testiculaire, Lyon Médical, 1886, p. 101 et seq.
- 7 Tourneaux et Herrmann, Dictionnaire Ency. des Sciences Médicales, 1886, p. 525 e¢ seg.; and Weil, quoted before.
It would not, I think, serve any useful purpose to recapitulate the literary researches of these authors, and in what follows it is proposed to lay stress upon points which seem more particularly worthy of notice, and which have not had the attention they may be thought to deserve.
At the third month a distinction can hardly be drawn between the plica gubernatrix and its contents, the gubernaculum. The two together are a delicate band about 75th inch long, continuous below with the abdominal wall, a little external to the hypogastric arteries, and attached above to the genital string (Pl. XVII. fig. 48), right or left, as the case may be. A proper appreciation of the early upper attachment of the gubernaculum is of some importance, because, as Bramann! says, authors are not very explicit in their statements concerning it.? For instance, if, as some would have us to suppose, it were thought that the gubernaculum was, from the beginning, inserted into the lower end of the Wolffian body or testicle, a difficulty would arise aS soon as an attempt was made to trace corresponding parts in the male or female. Every one would admit that the round ligament of the uterus is analogous to the gubernaculum testis, and yet the round ligament does not accord with current descriptions of the gubernaculum, inasmuch as it is attached neither to the parovarium nor to the ovary itself, but to the uterus. The cause of the dilemma and its explanation are alike obvious, if the earliest insertion of the gubernaculum into the genital string be recognised; later, it will be seen that in the male the gubernaculum acquires, during the 3rd, 4th, 5th, and 6th months, attachments to the epididymis, to the testicle, and to the peritoneum of the back of the abdomen. As it acquires these new attachments it comes to lie behind the vas deferens, which, as Bramann points out, crosses over its uppermost part.
- 1 Ibid., p. 320. 2 Quain’s Anatomy, 9th ed., vol. ii. p. 898; also fig. 805; also Henle, Handbuch der Hingeweidelhere des Menschen, 1886, p. 340, fig. 255.
A correct appreciation of the way in which the gubernaculum attaches itself first to the vas, then to the vas and epididymis, and afterwards to the testicle as well, explains several anomalies. For instance, it occasionally happens that whilst the testicle and epididymis is retained within the abdomen by adhesions or other causes, nothing but the vas deferens, together with a processus vaginalis, reach the scrotum. Or, as Cloquet,? Curling, Follin, and Godard have shown, the vas and epididymis .may proceed towards the scrotum, whilst the body of the testicle remains within the abdomen. <A specimen in Guy’s Hospital Museum ? illustrates this fairly well. My note of the specimen says, that on the right side the testicle is within the scrotum, but that the tunica vaginalis is patent, forming the sac of a congenital hernia. On the left side the testicle is undescended, and just’ within the internal ring. The epididymis is apparently pulled away from the testis, and lies within the neck of a process of peritoneum which occupies the inguinal canal. The peritoneum in the vicinity of the testicle is drawn into folds and pleats as if by dragging. The account which has been given of the superior attachments of the gubernaculum would explain these anomalies if two assumptions be allowed: first, that the upper attachments of the gubernaculum sometimes fail to develop properly ; and, secondly, that the gubernaculum is capable of dragging the testicle through the abdominal wall, and finally depositing it in the scrotum, or elsewhere. With regard to the first point, I think it will be allowed that if it can be shown that the upper end of the gubernaculum may have no attachment at all, either to the vas deferens, the epididymis, or to the testicle, 1t will be admitted that they may be sometimes deficient in a less degree. In a very large and full-term anencephalic monster, the scrotum had exactly the appearance which it presents in cryptorchids, very small and curiously pinched together. When the abdomen was opened there was only a trace of a processus vaginalis on either side, but the gubernaculum was large and well developed. On the left side, however, the gubernaculum, instead of having its ordinary connections, spread out in a thin and wide leash of fibres, contained within a fold of peritoneum (fig. 52). On the right side of the body the attachments of the gubernaculum seemed to be normal! It is also not without interest to note the condition of the scrotum; it looks as though the testicles had sent word to say they were not coming, and, in consequence, it had not developed. Perhaps I may mention here an embryo between the 3rd and 4th months,’ in which, had it arrived at maturity,
- 1 There is a specimen which illustrates this in the museum of University College, Sp. 1137.
- 2 Cloquet, Recherches Anatomiques sur les Hernics de Abdomen, Paris, 1817, p. 238 et seq.
- 3 Sp. 2339°,
Fig. 52. T, testicle; EHy., epididymis; S4 and V, spermatic artery and vein ; V.d., vas deferens ; G.T., gubernaculum testis.
- 1 This specimen is in the museum of St Bartholomew’s Hospital, No. 3607a.
- 2 Also in the museum of St Bartholomew’s Hospital, Sp. 36708.
the state of affairs would have been exactly the reverse. In this specimen the testicles and gubernacula seemed as well developed as they usually are at that age, but no trace of a penis or scrotum or anus could be found, although there were one or two indistinct pores in the perineum. Obviously, in this case, the testicles could never have accomplished their transition. The second assumption, that the gubernaculum is capable of traction, has been maintained by some authors and denied by others. Up to this point the present inquiry has favoured the views of Cleland, Sappey,? and Kolliker? who seem to believe that in the transition of the testicle the gubernaculum is passive, but that, whilst the testes themselves do not move, their surroundings grow, and, at the same time, the gubernaculum shortens but does not retract—a process analogous to those which produce the relations of the spine and its contents. However, these hypotheses fail to account for certain interesting phenomena which sometimes attend the transition of the testes. The muscular structure of the gubernaculum is, I think, unquestionable, and it seems irrational to deny its tissues the exercise of their function, namely, that of contraction. Moreover, in a moment we shall see that the lower muscular fibres of the gubernaculum are found to be attached—in addition to the pubes, root of penis, and scrotum—in the perineum and in Scarpa’s triangle. Is it not significant that the testicle sometimes migrates into either of the last-named regions ? Sometimes it lies close to the anus; in case mentioned in the Lancet* it was two centimetres from that orifice and immovably fixed, and presently other instances will be forthcoming. Now it seems hard to conceive how the testicle could have arrived in this position by any process of growth and development. Moreover, during the last stages of the transition, the pyriform portion of the gubernaculum shortens. In a foetus, 12 inches long, from crown to sole of foot (the legs outstretched), and which had a mesorchium and gubernaculum the same as that figured in an earlier part of this ‘lecture (fig. 49), the plica gubernatrix and the portion of the gubernaculum between its layers measured 2 inch long; whilst in a fully-developed foetus, 154 inches long, and in which the testicle was descended and the processus vaginalis capacious, on looking within that pouch there was no plica gubernatrix or trace of the part of the gubernaculum which lies within that fold of serous membrane. Perhaps these foetuses place the matter in too favourable a light, and therefore a few more measurements ought to be tabulated. It seems as though the pyriform portion of the gubernaculum does not bear a very constant proportion to the size of the foetus. It was always measured from within the peritoneum and as it lay in the plica gubernatrix; the extra-peritoneal portion, that which spreads out to the pubes, scrotum, and perinzeum, could not always, for obvious reasons, be measured. For the present, instead of pursuing this line of argument any further, the lower attachments of the gubernaculum may be mentioned. This branch of the subject has been rendered clear and familiar by the writings of Curling,’ and therefore a brief description will suffice. Since, however, that author based his observations mainly upon dissected specimens, it is proposed, where necessary, to mention the appearances seen in histological sections, prepared as usual by the paraffin method.
- 1 Cleland, Mechanism of the Gubernaculum Testis, Edinburgh, 1856.
- 2 Sappey, Traité d’ Anatomie Descriptive, vol. iv. p. 581.
- 3 Kolliker, Entwicklungsgeschichte, p. 997.
- 4 Baudry, Lancet, Sept. 1882, p. 454.
No. Size of Footus. Position of Testis. Length of: Gubernaculum.
1 7 in. Within abdomen. Pyriform #,in.; leash 34 in.
2 84 in. Within abdomen. Pyriform 43, in.
3 84 in. Within. abdomen. Pyriform , in.; leash. 33, ends on tuber ischii.
4 12 in. Within abdomen. Pyriform 8; in.
5 154 in. Fully descended. None.
6 16 in. On crest of pubes; pro- | Pyriform , incessus 2; in. further.
7 174% in. Bottom of scrotum. Barely 32, in. 8 19 in. Bottom of scrotum. #5 in.
At the third month of intrauterine life, the lower end of the gubernaculum looks to the naked eye as if it ended at the peritoneum; but, as we have seen, its tissues can be followed in the histological sections into the substance of the abdominal wall. Here they enter the hollow of. the descending cremaster and external spermatic fascia, interlacing and interpenetrating the fibres. At this age, moreover, the gubernaculum consists of two sorts of tissues. Its main bulk is made up of round and spindle-shaped cells, each with a deeply-stained, round or oval nucleus. Many of the elongated cells seem to run from the abdominal wall towards the genital string, and they have a decided likeness to unstriped muscular tissue, and, as that substance is afterwards found in abundance in the place they occupy, it is probable that they are of that nature. The other tissue of which the gubernaculum is composed is that which I have previously spoken of as the ascending cremaster. This consists of a few of the innermost muscular fibres of the abdominal wall, which runs a short distance along the gubernaculum, lying immediately beneath its peritoneal investment, At the third month their presence can just be recognised, at the fifth they are no longer doubtful, and at the seventh or eighth are abundant and distinctly striated. These ascending fibres have been recognised from the time of John Hunter, and since then most authors have acknowledged their existence.! They are better marked in some animals than in man; for instance, in the hedgehog they are very easily seen, and Hunter seems to have derived his ideas from that animal. Their presence is also clearly shown in various series of histological sections of rabbits’ embryos, ranging from the 15th to the 17th day after impregnation.”
- 1 T, B. Curling, 4A Practical Treatise on the Diseases of the Testicles, 4th ed., 1878, p. 17 e¢ seq.
The gubernaculum grows rapidly after the third month, and the part of it immediately below the testicle assumes a bulbous shape, and, when quite fresh, looks dense and greyish-white. Below this bulbous part its lower end spreads out in a leash of unstriped muscle fibres, which seem both to blend with and pierce the abdominal wall, and which can be seen quite plainly by dissection.
- 1 Observations on Certain Parts of the Animal Oeconomy, by John Hunter, 1786.
- 2 Quite recently (Jan. 1888), Dr Klein has kindly sent me a memoir by Professor Weil ("Ueber den Descensus Testiculorum nebst Bemerkungen ueber die Entwickelung der Scheidenheute und des Scrotums," Zeitschrift fir Heilkunde, Bd. v., 1884, p. 225 et seg.). In this memoir a full historical reswmé is given of the gubernaculum and processus vaginalis. Moreover, thé subject is studied by means of histological sections, and it is not without interest to compare the results with those which I have from an independent standpoint given. This author (p. 248) describes and depicts the gubernaculum and processus as being clearly established at the end of the second month. As regards the processus this seems too early, and, judging from his sketch, the embryo in which the appearances were seen was as old, or even older than, those which I have considered to have been of the third month. However, the determination of the age of embryos is always a doubtful point. Weil recognises in the gubernaculum both spindle-shaped cells and striped fibres, together with some blood-vessels, which arise from the spermatic and epigastric arteries (p. 254).
At about the fifth month these fibres spread out fan-like in their main directions, namely, into Scarpa’s triangle, upon the pubes and root of penis, and towards the scrotum (Pl. XVII. fig. 53). By the sixth month, in a foetus which measured 84 inches long with its legs extended, a thick fasciculus passed onwards into the perineum, where it ended in the tissues about the anus and over the tuber ischii. In larger foetuses the perineal band of the gubernaculum is oftentimes better developed. In speaking of either the perineal prolongation of the gubernaculum or that into Scarpa’s triangle, which from its position and direction may be called its saphenous prolongation, it 1s necessary to use guarded language, for although they are both met with very frequently, yet their presence cannot always be affirmed. However, it is difficult to trace fibres of this description amongst foetal tissues, and at some period before the end of fcetal life the perineal band would probably exist. It is otherwise with the saphenous band, for although I have found it in most foetuses which had reached the fifth or sixth month, yet in those which were older it was unrecognisable, and therefore it may be concluded that it is transitory. The fact that it does exist helps to explain that variety of malposition of the testicle which is called crural inclusion. Medical literature contains the records of a great many cases of this, and I have to thank Mr Page of Newcastle for having sent me a portrait of a typical example.)
In a series of sections of the scrotum and perineum of a mature foetus, and in which the testes were fully descended (Pl. XVII. fig. 54), these perineal fibres were present, and also others, which united the processus vaginalis to the bottom of the scrotum. There are other circumstances which would render the existence of these perineal fibres highly probable, even if the foregoing evidence was wanting. A little while ago it was remarked that the testicle occasionally lay in the perineum, and I have before me a sketch, which Mr J. H. Morgan kindly sent me, of a case of a child in which the right half of the scrotum was smaller than the other, and the corresponding testis in the perineum. But the most significant point in the case was the presence of a band of fibres which held the right testis in the perineum near the anus. This band, as Mr Morgan’s note says, was attached near the anus, and caused the skin to pucker when the testicle was pushed forwards. It seems as though it were a common thing in these cases for the testicle to be held in the perineum by some sort of a band. Mr Treves has also informed me of a similar case, and in which, when the band had been divided with a tenotomy knife, the testicle was replaced in the scrotum. Mr M‘Carthy mentions a case, and Cloquet, in another, actually had an opportunity of dissecting out the band. The perineal attachments of this band may be either the tuberosity of the ischium, the external sphincter, or the skin. In Cloquet’s case it was attached to the tuber ischii. Perhaps it may not be out of place to mention that great caution is requisite in dealing with these cases. There is reason to think that the processus vaginalis may accompany the testicle in its abnormal excursion, and remain in communication with the general peritoneal sac. The consequences which may ensue, if, in the course of operations for the replacement of the testicle, the processus vaginalis was opened without special precautions, are familiar to every surgeon. Mr M‘Carthy in his article mentions two deaths from peritonitis after operations upon cases of this kind.
- 1 Kocher, Die Ki rankheiten der Mannlichen Geschlechtsorgane, 1887, p. 570. et seq., collates a number of cases of malposition.
A last reference to the scrotal fibres of the gubernaculum may be permitted, more especially as doubt has been cast upon their existence. Their presence is usually affirmed, because an attempt to draw the newly-descended testis upwards out of the scrotum causes the end of that sac to invert, and, moreover, because they can be seen by dissection. Both of these statements are, I think, correct; and, in addition, the presence of scrotal fibres is shown in the series of sections of a fully developed scrotum (Pl. XVII. fig. 54). Nevertheless, those who have attempted to trace smooth muscle fibres with the scalpel will readily understand why opinions vary.
- 1 Quain’s Dic. of Medicine, 1882, p. 1606.
- 2 Recherches sur les Causes et 0 Anatomie des Hernies Abdominales, Paris, 1819, pp. 24, 25.
- 3 Bramann, 7bid., p. 334. Curling, Diseases of the Testis, 4th ed., 1878, p. 17 et seq.
It may be advantageous to enumerate the attachments of the gubernaculum in the order in which they seem to develop, viz., (1) abdominal ; (2) pubic and saphenous; (8) perineal and scrotal. Placing the saphenous upon one side as being, perhaps, inconstant, the functions attributed to the abdominal, pubic, and scrotal are as follows:—The testicle is brought by the abdominal into the ostium of the processus vaginalis, through the canal by pubic, and deposited in its resting place by the scrotal. With regard to the first of these actions, it may be said that the process is not quite so simple as at first glance it seems to be, If we compare the position of the testicle of a five months’ foetus (figs. 51 and 57) with its position in one of the seventh month (fig, 49), it is evident that in the younger embryo the gland lies close to the ostium of the processus vaginalis, whilst in the older embryo it seems to have re-ascended a little way into the abdomen.! This re-ascent, which seems a constant occurrence, hag been permitted by a luxuriant growth of the mesorchium and by an elongation of the intra-abdominal portion of the gubernaculum. The occurrence is unexpected, and seems to indicate a peculiarity in the action of the gubernaculum, and, in a sense, to detract from the importance given to its abdominal attachment. By its abdominal attachment the gubernaculum can only for a time hold the vas deferens, and afterwards the epididymis and testicle near ostium of the processus vaginalis. The actual passage of the testicle through the inguinal canal begins during the seventh month, and by that time the vaginalis is ready for its reception, and the gubernaculum has acquired other attachments to the pubes, which may be supposed to afford it a fixed point from which to act and draw the gland, first into the ostium, and afterwards into the canal. The scrotal band, however, seems deficient in firm attachments and unfitted for the duty it is supposed to perform. Various circumstances indicate that, in bringing the testicle through the abdominal wall, the gubernaculum must exert a certain amount of force. For instance, if a foetus be chosen in which the testicle is about to pass through the abdominal wall, and traction be made upon the gubernaculum, it is clear that as the testicle travels towards the scrotum, not only the mesorchium and its contents and the processus vaginalis, but also the peritoneum of the back of the abdomen, moves with it.
- 1 Bramann, p. 620.
In consequence of this locomotion of the serous membrane, the cecum and ilium on the right side, and the sigmoid flexure upon the left, become lower in the abdomen, a circumstance upon which both Scarpa and Wrisberg have commented,) and as I proceed other reasons for this belief will be forthcoming. Now, it is obvious that the scrotal attachments of the gubernaculum are ill fitted to afford resistance to the action of the muscle, and I conceive that it is by means of its well-attached perinzal fibres that the gubernaculum is enabled to effect its purpose, the scrotal band merely influencing the final position of the gland. In attributing the final passage of the testicle through the abdominal wall into the scrotum to the traction of the gubernaculum, I have not thought it necessary to parade the various theories which have been offered as an explanation of the phenomenon. The weight of the organ has been invoked, also certain suppositious respiratory efforts, and, finally, a sort of hernial protrusion.2, The first of these theories has been demolished by Sappey, who remarks that during the period of transition the fcetus usually lies in the uterus with its head downwards. The second theory calls for no comment, for there is nothing to show that the foetus breathes before birth; rather the contrary. The last theory is more plausible, and has recently been revived,? but seems to rest upon an obvious ambiguity. The term hernia is used in two different senses. Sometimes it implies merely an anatomical condition, namely, the escape of organs from their containing cavities; at other times the word hernia is used to connote a pathological change ; but, used in its pathological and not in its anatomical sense, it is clear that the word hernia ought not to be used in explaining the transition of the testicle, for the simple reason that the pathology of hernia is quite undecided. The question still remains to be settled whether inguinal hernia is due to (a) a defect in the abdominal walls; (6) an elongation of the mesentery ; or (c) a general defect of the peritoneum. However this may be, I hope presently to adduce evidence to show that the gubernaculum testis may have something to do with the pathology of congenital czecocele and of infantile hernia.
- 1 See paper by author, Roy. Med. Chir. Trans., vol. 1xix. p. 505.
- 2 Sappey, Zraité d’ Anatomie Descriptive, vol. iv. p. 606.
- 3 J, Bland Sutton, An Introduction to Gencral Pathology, 1886.
The anatomy of the cremaster is well known, and does not call for lengthy notice. Where its fibres are attached to Poupart’s ligament, they are also continuous with the internal oblique muscle. Its inner tendinous attachment is into the pubes, close to the insertion of the internal oblique muscle.’ Its loops descend in front of the spermatic cord, and become larger and longer as they descend, and some of them may invest the testicle. Upon these points there is perhaps no dispute, but a variety of opinions prevail as to the parentage of the muscle. It would not be inaccurate to say that there are two main views upon this question. Some think that the cremaster is created out of those striped muscular fibres which ascend the gubernaculum from the abdominal wall, and which I have called the ascending cremaster. Others believe that it is derived from the lower fibres of the internal oblique, and which have accompanied the testis in its transition.? The first of these opinions originated with Hunter, who saw that the fibres of the ascending cremaster of the ram became inverted when the gubernaculum was pulled downwards beyond the abdominal wall? Judging from its characters in the human embryos which have been described above, it is probable that this same thing would happen to them. I have assumed in the foregoing that the chief labour of transition falls upon the smooth muscular elements of the cremaster. It cannot be denied, however, that the striped fibres may also assist and help to draw the testicle as far as their own lower attachments, but obviously not beyond, as some have supposed. The ascending cremaster of the human embryo is so trivial, that perhaps it ought to be looked upon as a mere survival of a muscle which, in some of the lower animals, is more active and better developed.
- 1 Quain, 9th ed., 1882, vol. i. p. 32.
- 2 Ibid., pp. 7, 8.
- 3 A very clear and correct account of the cremaster is given by Debierre and Pravaz (Lyon Médicale, 1886), so far as the muscle can be studied by dissection. They also give an excellent epitome of the views of the various authors,
We now come to the second theory, that the cremaster is an appendage of the internal oblique muscle, displaced towards the scrotum by the testicle in its transition. From what has gone before it will be seen that this proposition is only true in a very limited sense, namely, so far as it may be taken to imply that the descending cremaster is developed in connection with the oblique muscle. The histological specimens which have been described in the earlier part of this lecture seemed to show that the muscular fibres, which were called the ascending cremaster, developed in close connection with the internal oblique; perhaps it would not be incorrect to say that they developed as an outgrowth of that muscle. But it must not be ignored that, at first, no distinction can be drawn between the internal oblique and transversalis muscles, so that the latter might claim a share in the process. However, the part of the proposition which attributes the origin of the cremaster to the transition of the testicle is not borne out by the specimens. They show that the external cremaster develops long before that event, and indeed before the processus vaginalis has appeared. Towards the end of the seventh month of intrauterine life the processus vaginalis is so far ahead of the testicle that it must have anticipated the testicle in any action that organ might have had in carrying down the cremaster. It would be more rational to attribute the formation of the muscle to the gradual advance of the peritoneal pouch, rather than to that of the sexual gland. In the later stages, towards the eighth month of intrauterine life, the processus vaginalis is so voluminous that it would be rash to deny it a part in at least modifying the cremaster; but it is so difficult, perhaps impossible, to dissect the muscle in the foetus, that I have been unable to obtain definite information upon this point.
The Superior Attachments of the Gubernaculum, the Mesorchium, and Placa Vascularis
The superior attachments of the gubernaculum have already been described, with the exception of the peritoneal prolongation. It may be remembered that they varied according to the stage of development, the gubernaculum being attached first to the genital cord, then to the cord and epididymis, and finally to both of those structures, and also to the body of the testicle. The prolongation which the gubernaculum sends upwards behind the testicle to the peritoneum is chiefly confined to the plica vascularis, but it has sometimes a wider distribution. It was well marked in a foetus 84 inches long (legs extended), and presumably of about the sixth month; and in others, 12 inches long, and presumably towards the end of the seventh month, the plica vascularis contained its fibres in great abundance, and they probably reached the organs with which the fold is at various times connected, namely, on the right side with the cecum, vermiform appendix, or the ilium and mesentery, and on the left side with the sigmoid flexure. Without doubt, the main portion passes to the mesentery, which, at the eighth month, is common to the czecum and ilium, or to the mesentery of the sigmoid flexure. Both the plica vascularis and its contents, especially the muscular fibres, are of physiological and pathological importance. When the lower end of the right gubernaculum of the fetus of the seventh or eighth month, whose mesorchium has been figured in an earlier part of this lecture (fig. 49), was pulled downwards, the processus vaginalis, vas deferens, epididymis, testicle, mesorchium, with its plica gubernatrix and plica vascularis, the cecum and vermiform appendix, the ilium and mesentery, and peritoneum of the back of the abdomen, all glided downwards towards the inguinal canal and scrotum, and traction on the left gubernaculum had the same effect upon the sigmoid flexure. The attachment of the gubernaculum to the various parts of the sexual apparatus is sufficient to account for their displacement, and the other viscera follow, because they are connected with the epididymis by the plica vascularis. Doubtless, the serous membrane of that fold may be sufficiently inelastic to bear whatever strain there may be, but presently it will be seen that due regard must be paid to the upward prolongation of the gubernaculum. These muscular fibres have an extensive connection with the peritoneum, which lines the back of the abdomen, and doubtless bring about the locomotion of that membrane, which is seen in the transition of the testicle, and in many cases of hernia. That the serous membrane of the back wall of the abdomen is much looser than the rest has been repeatedly pointed out in the earlier part of this lecture; it is underlaid by abundant loose areolar tissue and fat, and is easily displaced and thrown in folds. The peritoneum, which lines the front wall of the abdomen, is, except near the epigastric and hypogastric arteries, intimately bound to the abdominal wall. In adult subjects the union of transversalis muscle, transversalis fascia, and peritoneum is so close, that sometimes it would hardly be incorrect to say that the muscular fibres of the transversalis were inserted into the peritoneum. For these reasons the peritoneum of the front wall of the abdomen is incapable of much displacement, and probably takes but a small share in the formation of large hernial sacs.
Before discussing the other attributes of the muscular fibres, the history of the plica vascularis, considered as a serous fold, may be mentioned. When the testicle glides down the processus vaginalis—which has preceded it—into the scrotum, it retains in a greater or less degree its peritoneal folds. For instance, at its lower end may still be seen in most foetuses the plica gubernatrix, and from the head of the epididymis another fold, the plica vascularis, runs upwards upon the back of the processus vaginalis towards the abdomen. Owing to its connection with the globus major the plica vascularis is easy to recognise, and it not uncommonly persists throughout life. For instance, Camper, in his Icones Herniarum, gives excellent representations of it; Sir Astley Cooper also depicts it;? and Sappey ® says that the visceral layer of the tunica vaginalis forms a sort of small mesentery, which contains the testicular vessels; but none of these authors seem to have recognised the developmental significance of this fold. The plica vascularis is usually distinct in a foetus in which the testicles have just reached the scrotum, and it extends upwards along the back of the processus vaginalis into the abdomen (fig. 45); or, if that passage has been obliterated, a fold, which occupies its position, extends from the internal abdominal ring towards the mesentery either of the cecum and ilium, or of the sigmoid flexure. The main interest of the plica vascularis depends upon its relation to undescended testis and various forms of congenital hernia.
- 1 Camper, Jcones Herniarum, ed. by 8. J. Semmerring, 1801, Tab. ITI. figs. 3 and 4,
- 2 Cooper, Anatomy and Surgical Treatment of Abdominal Hernia, pl. v. fig. 6, and elsewhere.
- 3 Traité @ Anatomie Descriptive, vol. iv. p. 602.
That the transition of the testis may have an influence upon the last stages of the migration of the cecum I have elsewhere endeavoured to show,! and have published cases in which, when the testicle was undescended and lay within the abdomen, the cecum remained at or near the liver. On the other hand, I have met with a case in which the right testicle was fully descended, although the cecum was firmly adherent to the liver? This abnormality occurred in an anencephalic monster, and I am accustomed always to examine these creatures with care, because they seem particularly liable to intrauterine peritonitis and other complaints,and therefore afford most interesting material. The foregoing case has been mentioned, because it~ tends to place the matter in a light not very favourable to my hypothesis, but not, however, in an absolutely unfavourable light. In the first place, it has merely been claimed that the testicle in its transition wnfluenced the last stages of the migration of the cecum, and in the case which has been mentioned the cecum must have become adherent to the liver at such an early age, that it could neither have been influenced by the movements of the testicle, nor by its own adherence have impeded that organ. Continuing the pathological bearings of the plica vascularis, there is reason to believe that that fold may in another way be a factor in the pathology of undescended testicle. In reading of cases of abdominal inclusion of the testicle, it is impossible not to be struck by the repeated references to the presence of adhesions. Without doubt some of these are simply inflammatory,’ due to intrauterine peritonitis;* but in others it seems safe to infer that the so-called adhesion was in reality the -plica vascularis which had persisted in an unusual degree. Such a case as the following is not without significance :—Cloquet found in an aged man the left testicle an inch inside the ring, and fastened to the sigmoid flexure by a band—fibrous, white, round, and very strong} Curling mentions another case of imperfect transition, in which the testicle was adherent to the gut, but his observation is based upon clinical evidence,? and I am unable to ascertain that he clearly appreciated that the so-called adhesion was of the nature of the plica vascularis. However, he agrees with Cloquet in believing that congenital bands, which seem to possess the characters of the plica vascularis, may impede the transition of the testicle.
- 1 “ Abnorinalities of the Ceecum and Colon, with Reference to Development,” British Medical Journal, September 1882, p. 575.
- 2 The specimen is described in Path. Soc. Trans., vol. xxxvii. p. 250, and is in the museum of St Bartholomew’s Hospital.
- 3 Testicle retained in the abdomen by adhesion to the sigmoid flexure of the colon. John Wood, "Adhesions due to Inflammation from Mesenteric Disease in Foetal Life," Path. Trans., vol. viii., 1856, p. 265.
- Simpson, Ed. Med. Jowrn., vol. lii. p. 17 et seg. We have also to note the possibility that the retained testicle may in some rare cases set up inflammation in its vicinity.
The plica vascularis seems at times to play a different part. It occasionally happens that the cecum, vermiform appendix, iltum, or sigmoid flexure may accompany the testicle into the scrotum, and give rise to various forms of congenital hernia. In cases of this sort a peritoneal band is very often found passing upward from the head of the epididymis to the herniated gut. The spermatic vessels usually lie in this fold, and it has the characters of the plica vascularis. Wrisberg Lobstein, Sandifort,> and others® have mentioned this circumstance, and the first and last named authors seemed to appreciate clearly the meaning of the connection between the gut and the testicle. They assumed that, owing to persistence of the plica, the gut had been dragged down by the testicle in its transition. However, although there is an element of truth in this assumption, there is reason to doubt whether it is the whole truth. I have mentioned elsewhere’ a congenital czcocele, which I was so fortunate as to find in an infant, and in which there was no fold extending from the testicle to the gut, but in its place a quantity of unstriped muscular fibres, which turned upwards from the perineum and back of the testicle towards the cecum and peritoneum of the back of the abdomen. These muscular fibres are clearly the upward prolongation of the gubernaculum, which has already been mentioned, and which has been claimed to aid in the locomotion of the peritoneum of the back of the abdomen which accompanies the transition of the testicle. In this respect they seem to have had a share in causing the ceecocele. In another cecocele sent to me by my friend, Mr Maud, the muscular band was also present; and Professor Cunningham has very kindly written to inform me of a case in which there was a band of fibres so strong “that it does not fall far short of the platysma,” and which he considers “as having been the active agent in producing the hernia (of the cecum), and as having become hypertrophied in the process.” In this case there was also a second isolated peritoneal pouch, which I will mention again in speaking of infantile hernia.
- 1 Recherches sur les Causes et ? Anatomie des Hernies Abdominales, Paris, 1819, p. 23.
- 2 Ibid., p. 24.
- 3 Wrisberg, ‘‘Observationes Anatomice de Testiculorum ex Abdomine in Scrotum descensu,” &c., Comment. Soc. Reg. Scient., Gotting., 1800, p. 173 et seq.
- 4 Quoted by Wrisberg.
- 5 Sandifort, Icones Hernie Inguinales Congenite, 1781, p. 12 et seq.
- 6 Scarpa, On Hernia, Wishart, Edinburgh, 1814, p. 194, art. on the ‘ Natural Fleshy Adhesion”; also F. Treves, ‘‘ Hernia of the Cecum,” Brit. Med. Jour., Feb. 19, 1887, p. 385.
- 7 Med. Chir. Trans., vol. lxix. p. 505.
The upward prolongation of the gubernaculum is also met with under other circumstances. Normally it persists as the muscular fibres which Henle and Cruveilhier call the internal cremaster ;1 and presently it will be seen to have an important bearing upon the pathology of infantile hernia. But before mentioning this, perhaps I may point out that the plica vascularis is found very commonly in congenital and funicular hernize, and is an important guide to the position of the spermatic vessels. It is unnecessary to point out what serious results ensue when these vessels are injured in the performance of operations.
The peritoneal prolongation of the gubernaculum is, I think, an important factor in producing certain sorts of hernial sacs, especially the sacs of infantile hernia. This opinion is based upon evidence derived from such specimens as the following :— There is a specimen in the museum of St Bartholomew’s Hospital,? which I have had the opportunity of dissecting, in which the processus vaginalis is represented by a long tube,
- 1 Since my paper upon Ehcysted and Infantile Hernia, and in which this view was put forth, a similar observation has been made quite independently by Debierre and Pravaz (ibid., p. 143), but without reference to hernia.
- 2 Sp. 21408.
which extends from the internal abdominal ring to just above the epididymis. This tube communicates with the general cavity of the peritoneum by a small aperture, a quarter of an inch in diameter, which occupies the usual position of the internal abdominal ring external to the epigastric artery. A probe introduced into this opening showed that the processus vaginalis was occluded an inch from the upper end, but in the remainder of its extent its cavity was almost half an inch in diameter above and one and a half below. Behind the superior part of this serous tube a hernial sac protruded from the peritoneum in such a way that the anterior wall bulged slightly into the cavity of the processus vaginalis, Attached to the lower extremity of this protrusion and to its posterior wall were strong bands of unstriped muscle fibre intimately related to the spermatic vessels. The end of the sac to which these were attached was conical and sharply-pomted. This specimen I have described elsewhere, and considered it to have been a variety of infantile hernia.! It is perhaps unnecessary to argue that the origin of the pomted hernial sac was due to the action of the muscular fibres, and, further, that these fibres were a part of the peritoneal prolongation of the gubernaculum. The isolated peritoneal pouch seen in Professor Cunningham’s ‘specimen lay towards the outer side of the true sac of the congenital cecocele; and although it had no connection with the abdominal peritoneum, “was drawn out above into a fine point Lene and has doubtless been dragged down by some stray fibres” (of the gubernaculum). In other cases of infantile hernia the band is also clearly marked, and it may perhaps suffice to mention a single well-marked instance. By an infantile hernia is meant a variety of congenital hernia, in which the processus vaginalis is not obliterated, but remains in the condition in which it is found in congenital hernia, except that it may be occluded to a greater or less degree near the internal abdominal ring. However, ocelusion is probably the exception, and when it does take place the manner of its occurrence can be traced. In addition to this non-obliteration of the processns vaginalis there 1s, in infantile hernia, a second pouch of peritoneum, which descends behind the other and bulges into it.
- 1 Med. Chir. Trans., vol. 1xix. p. 513.
Sometimes the projection is slight, but at others is so great that the true hernial sac—7.e., that which contains the herniated viscus—almost seems to hang from near the ostium of the processus vaginalis, like a sac pendent from the ring. It may render this brief description clearer if I add that, to gain an entrance into the true hernial sac from in front, it would be necessary, first of all, to cut the front and back walls of the non-obliterated processus vaginalis, and then the wall of the true hernial sac, as Hey’ calls it. There is reason, however, to believe that the pathology of infantile hernia is in some way connected with the plica vascularis, because in some specimens the remains of that fold can be seen extending from the epididymis to the lower end of the true hemial sac.2 In other cases, in which the serous membrane has probably been dissected away, instead of the plica a strong band of smooth muscle fibres unites the back of the epididymis to the extremity of the true hernial sac (see fig. 55). This band represents the peritoneal prolongation of the gubernaculum, and, besides being intimately related to the spermatic vessels, runs upwards along the back of the true hernial sac towards the abdomen. When we recall the influence which the gubernaculum has in forming the processus vaginalis itself, or, as Cloquet has maintained, hernial sacs of various sorts, it seems reasonable to argue that it is an important factor in the pathology of infantile hernia.
Fig. 55. — Infantile Hernia. A, upward prolongation of gubernaculum with spermatic artery in its midst ; B, true spinal sac with double walls; C, body of testicle.
- 1 It is interesting to note that in Hey’s case of infantile hernia the sac con tained the cecum.
- 2 E.g., Sp. R. 24, St Thomas’s Hist. Museum, Med. Chir. Trans., fig. 4, p. 493.
Relation of the Vas Deferens and Spermatic Vessels to Processus Vaginalis
The Recurrent Branches of the Spermatic Artery.
It is unnecessary to premise, that as the testicles migrate down the processus vaginalis, the spermatic vessels and vas deferens accompany them, and acquire certain definite relations which it is important to recognise. If a foetus be chosen in which the testicles have completed their migration, but in which the processus vaginalis is capacious and still in communication with the peritoneum, the relations of the vas deferens and spermatic vessels are usually as follows:—The artery and vein run from the upper part of the abdomen to the outer side of the ostium of the processus vaginalis, and then along the back of that sac, lying in the plica vascularis, as far as the epididymis, where they divide into their two main divisions, one going to the body of the testicle and the other to epididymis ; the vein usually les to the mner side of the artery. The vas deferens, on the other hand, runs upwards from the neck of the bladder round the hypogastric arteries towards the inner and lower part of the ostium of the processus vaginalis, and thence along the posterior wall of that sac, to reach the globus minor. In the last part of its course the vas deferens lies internal to the vessels, and sometimes quite apart from them (fig. 55). These relations are interesting, because they help to explain the separation of the vas deferens from spermatic vessels seen in many cases of hernia. The London museums contain so many examples of this condition, and it seems such a common and well-known occurrence, that it is perhaps unnecessary to adduce instances; but in nearly all of them the vas deferens lies well to the inner side of the vein and artery. Lawrence! mentions numerous instances of this occurrence, and attributes the separation to the distensile force of the hernia. Later, he says the same condition may be found in a small hernial tumour,? and the specimens in museums fully bear out this statement; and they further suggest that mere distension could not have been the sole cause of the separation of the vas from the vessels, but that the predisposing developmental factor which has just been mentioned must also be taken into consideration; indeed, in some instances of congenital hernia, it seems as if the structures in question can never have been together. I hope to deal with this question more fully at another time, and will therefore not endeavour at present to discuss other varieties of the condition.
In endeavouring to ascertain whether the spermatic artery accompanies the transition of the testicle pari passu with the peritoneum and processus vaginalis, or whether it was drawn in a greater degree towards the scrotum, several interesting circumstances came to light. Text-books on anatomy usually state that the spermatic artery gives branches to the peritoneum, and on the left side others are frequently supplied to the sigmoid flexure. It suggests itself that these branches may afford information bearing upon the question of the relative movements of the artery and of the peritoneum; and in numerous dissections I have found the spermatic arteries give off recurrent branches to the peritoneum. The largest of these begin near the internal abdominal ring, and run 4 or 5 inches upwards, giving off branches and gradually dwindling (Pl. XVII. fig. 56).
- 1 Lawrence, On Hernia, p. 212.
- 2 Tbid., p. 213.
- 3 See more particularly Turner on the existence of an anastomosing system of arteries between the visceral and parietal branches of the abdominal aorta, Brit. and For, Med. Chir. Review, July 1863.
The inference to be drawn from their presence seems obvious, namely, that the spermatic artery is displaced more than the peritoneum. But, in addition, the recurrent branches of the spermatic artery seem to have a pathological bearing, and it is not improbable that they have something to do with the formation of these secondary pouches, which are found upon the hinder wall of the sacs of some congenital hernia. That these recurrent branches may be also found at the back of the processus vaginalis is shown by various specimens. For instance, there is a dried hydrocele in St Bartholomew’s Hospital Museum whose vessels have been injected, and in which the recurrent branches are quite clear;! also, there is in the Dupuytren Museum a hernial sac, which has been treated in the same way, and which has the same recurrent arteries upon its hinder wall.2 Now, the principle seems established that vessels which are related as these recurrent branches are to the peritoneum may throw that membrane into folds? and it is not without significance to note that I have found a large obliterated vessel running in the fold of serous membrane, which formed a supplementary sac upon the back wall of a funicular hernia.*
The Closure of the Processus Vaginalis
A number of foetuses have been examined to see how the processus vaginalis becomes occluded after it has transmitted the testicle. There seems to be, as others have remarked, a strong tendency for it to close in two places, which are some distance apart, namely, just above the testicle and near the internal abdominal ring. This statement is founded upon ordinary anatomical evidence, the processus having been merely slit open with scissors. In some foetuses the serous canal was so attenuated that it was hard to discern, and it would have been rash to make any positive statement as to its patency or occlusion. But there was no evidence in any case to show that the processus vaginalis closed by adhesion. Its interior was always smooth and shining, like the rest of the peritoneum. Importance attaches to this point, because it has been thought that the processus vaginalis sometimes became closed by adhesions which afterwards became stretched into the sac of an encysted hernia. I have elsewhere endeavoured to combat this view upon various grounds, amongst which, perhaps, the most cogent are, first, that such adhesions have never been seen; and second, that the specimens which have been called encysted herniz belong to the infantile variety.
- 1 2753. 2 Sp. 295.
- 3 Treves, The Anatomy of the Intestinal Canal and Peritoneum in Man, London, 1885.
- 4 This specimen, and another which is of exactly the same nature, are in the museum of St Bartholomew’s Hospital, Nos. 2090 and 2140e.
In bringing these lectures to a close, I wish to thank Mr D’Arcy Power and numerous other friends for the valuable material they have placed at my disposal. And I am especially indebted to Dr Vincent D. Harris for many acts of kindness, and for his assistance and advice.
Page 53, line 28, for fourteenth read fourth. » 97, ,, 23, for 32 read 31. » ¢4, ,, 10, for 23 read 33. » ¢4, 4, 15, for 23 read 33.
Cite this page: Hill, M.A. (2021, April 13) Embryology Paper - Development and transition of the testis, normal and abnormal 4. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Paper_-_Development_and_transition_of_the_testis,_normal_and_abnormal_4
- © Dr Mark Hill 2021, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G