TESTICLE (NORMAL ANATOMY). 



977 



cated by an albuminous fluid, having the 

 ordinary properties of the secretions of the 

 other serous membranes. The office of this 

 membrane is to facilitate the movements of 

 the gland, so as to enable it to elude pressure 

 and escape violence. 



In some adult subjects the tunica vaginalis, 

 which was originally a process from the serous 

 lining of the abdomen, still retains its con- 

 nexion with that cavity. When the com- 

 munication is free, the sac is very liable to 

 receive a protrusion of some of the contents 

 of the abdomen, and become the seat of con- 

 genital hernia. Sometimes the communica- 

 tion continues through a contracted tubular 

 canal, which, though too narrow to admit the 

 transit of any of the viscera, is open to the 

 passage of fluid. In other cases the oblitera- 

 tion is partial, one or more isolated serous sacs 

 being left along the cord. It more often 

 happens, however, that after the upper aper- 

 ture of this process has closed a considerable 

 part of it below remains unobliterated, so that 

 the tunica vaginalis extends for some distance 

 upwards in front of the cord. Frequently, 

 also, although the obliteration is complete, 

 remains of the prolongation may still be found 

 in the form of a slender whitish filament, or 

 fibrous process, which is lost in the areolar 

 tissue in the anterior part of the cord, but 

 may sometimes be traced as far as the tunica 

 vaginalis. 



A small body of an irregular shape and 

 variable size, and of a pale red or pinkish hue, 

 is commonly found attached, often by a thin 

 pedicle, either to the upper extremity of the 

 testicle, or at the angle where the tunica 

 vaginalis passes from the body of the gland to 

 the epididymis. It is composed of a dupli- 

 cature of this membrane, containing some fine 

 areolar tissue and a number of small vessels. 

 It occasionally contains a little fat. I have 

 seen this little body in the testicle of the 

 fcetus whilst in the abdomen, and, in early 

 life, it is often of proportionally larger size, 

 and of a deeper red colour than in the adult. 

 It is quite distinct from the pedunculated 

 cysts often found attached to the head of the 

 epididymis. This little appendage to the 

 tunica vaginalis seems to correspond with, 

 and to be a type of, the remarkable omental 

 process attached to the superior part of the 

 testicle in the Rodentia and other animals. 

 That it is an unimportant structure in the 

 adult, is shown by its being frequently want- 

 ing. It may be of use, however, by slightly 

 increasing the secernent serous surface. 



The tunica Albuginea, or Tunica Propria, is 

 a dense, tough, inelastic membrane, composed 

 almost solely of white fibrous tissue, analogous 

 to the sclerotic coat of the eye. It completely 

 invests the body of the testicle, but not the 

 epididymis. Its external surface is covered 

 by the tunica vaginalis reflexa, to which it 

 intimately adheres. This tunic is divisible 

 into two layers, which can be separated only 

 by a tedious dissection, but which in certain 

 animals may be detached without difficulty. 

 The branches of the spermatic artery and 



VOL. IV. 



veins ramify in the substance of the tunica 

 albuginea, in canals bearing in their arrange- 

 ment some analogy to the sinuses of the dura 

 mater, which membrane the outer layer is 

 supposed to resemble. The smaller vessels 

 are chiefly distributed on the inner layer, 

 Avhich owing to its vascularity has been com- 

 pared to the pia mater investing the brain. 

 At the postero-superior border of the testicle, 

 and a little to its outer side, the tunica albu- 

 ginea forms an internal projecting body or 

 process, which lodges the blood-vessels and a 

 portion of the glandular structure of the tes- 

 ticle, called the rete testis. This body is 

 named, after the anatomist who first'described 

 it, the Corpus Hig/nnori. It has since, how- 

 ever, been called by Sir A. Cooper the medi- 

 astinum testis, and he describes it as being 

 formed by the tunica albuginea, which at that 

 part is divisible into three layers. The first 

 layer turns upon the spermatic cord, and 

 unites with the sheath which covers the ves- 

 sels. The second layer unites with a similar 

 layer on the opposite side, and forms a thick 

 substance, between the fibres of which inter- 

 stices are left for blood-vessels and absorbents, 

 whilst the internal layer, uniting with that on 

 the opposite side, as well as with the preced- 

 ing layer of the tunica albuginea, forms the 

 process called mediastinum, which projects 

 into the testicle between the tubuli, and it is 

 in this substance that the seminal canals of 

 the rete are placed. The mediastinum is 

 therefore composed of two bodies ; the upper 

 placed towards the spermatic cord, the lower 

 towards the centre of the testicle : in the 

 upper are placed the blood-vessels ; in the 

 lower, the canals of the rete. Its length 

 varies from six to eleven lines. 



II. Glandular or Secreting Structure. The 

 glandular part of the testicle is very simple, 

 and its tissue is more easily demonstrated 

 than the structure of most other glands. It 

 consists of numerous seminiferous vessels or 

 tubes, supplied with blood-vessels, lymphatics, 

 and nerves. Its colour is a greyish yellow or 

 brown, more or less tinged with blood, and is 

 paler in infants and old men than in adults. 

 The tubes are collected into numerous lobes 

 or lobules, invested by a fine areolar tissue, 

 which, detached from the interior of the tunica 

 albuginea, penetrates the gland, and sends out 

 lateral processes forming septa, which separate 

 and sustain the lobules. These septa at their 

 origin partake of the fibrous character of the 

 tunica albuginea, but as they converge towards 

 the superior border of the testicle, occupied 

 by the corpus Highmori, they become finer, 

 and are gradually resolved into a delicate 

 areolar tissue. The septa are traversed by 

 numerous blood-vessels, which minutely divide 

 in them before being distributed on the semi- 

 niferous tubes. Sir A. Cooper states, that 

 the inverted portion of the tunica albuginea, 

 forming the mediastinum testis, sends forth 

 numerous ligamentous cords, some of which 

 pass to the anterior edge of the testis ; whilst 

 others form shorter processes to support and 

 invest the lobes, being met by similar liga- 



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