THE TESTIS 1387 



back of the epididymis to the subcutaneous inguinal ring the spermatic cord can 

 be felt. The bulk of the cord is made up of its coverings, of which the cremaster 

 muscle is the most considerable, and of the pampiniform plexus of veins. On roll- 

 ing the cord between the finger and thumb the ductus deferens can be felt like 

 a piece of whipcord in the posterior part. 



The ductus (vas) deferens is thickened and nodular in tuberculous epididymitis. In vari- 

 cocele the dihated and elongated veins of the pampiniform plexus feel on palpation like a bag 

 of worms in the scrotum. It is important that the student, before studying diseased con- 

 ditions, should make himself familiar with the feel of the normal parts as mentioned above and 

 be able to identify them. 



Underneath the visceral layer of the tunica vaginalis, the body of the testis is covered by 

 a dense fibrous layer, the tunica albuginca, which accounts for the small extent of swelling in 

 orchitis as compared with epididymitis. The lymphatics of the testis run up in the spermatic 

 cord through the inguinal canal, and accompanying the spermatic vessels end in the lumbar 

 lymph nodes, below the level of the renal arteries. These nodes may be reached and removed 

 along with the vessels by making an incision in the loin above the inguinal (Poupart's) 

 ligament, and stripping the peritoneum off the posterior abdominal wall. 



On the right side of the perineum (left side of this figure) CoUes's fascia has been turned back 

 to show the superficial vessels. On the left side the superficial vessels have been cut away with 

 the anterior layer of the uro-genital trigone to show the deep vessels. 



The epididymis is the convoluted first part of the duct of the testis, about 6 m. (20 feet) 

 in length. Its three portions are in differing connection with the testis. Thus the cauda is 

 held in place by connective tissue, the body by the same medium; the caput by the vasa efferentia. 

 Thus, when tubercular disease begins here, the testis itself is more likely to be early involved. 



Ductus deferens. — The two extremities and the course of this involve several practical 

 points. About 4.5 cm. (18 in.) long, it begins, convoluted at first and with a distinct bend 

 upward, in the cauda epididymidis. It thence passes almost vertically upward at the back of 

 the testis and cord to the tubercle of the pubes. Entering the canal, it lies on the grooved upper 

 aspect of the inguinal (Poupart's) ligament, and then under the arching fibres of the internal 

 oblique and transversus, upon the transversalis fascia. Its position, characteristic feel, and 

 yellowish aspect are well-known guides in operations for varicocele and hernia, while it is alwaj-s 

 to be isolated and palpated when tubercular di-sease below is suspected. Leaving the canal 

 by the abdominal inguinal ring, it hooks round the inferior epigastric artery and then descends 

 into the pelvis over the external iliac vessels. Continuing its course downward and backward 

 over the side of the pelvis, it arches backward over the side of the bladder, superficial to the 

 obliterated hypogastric artery, and then deep to the ureter. The two ducts now help to form 

 the lateral boundaries of the external trigone, between the base of the bladder and the rectum. 

 They here become dilated and sacculated and then contract again to empty into the ejaculatory 

 ducts. 



The vesiculae seminales are diverticula growing out from the lower end of the deferential 

 ducts at an acute angle, one on each side. They lie below and lateral to the deferential ducts 

 and are related in front to the base of the bladder and posterior surface of the prostate, behind 

 to the rectum, and above to the recto-vesical pouch of peritoneum, which also descends to cover 

 the upper part of their posterior aspect. The normal vesicute seminales can scarcely be dis- 

 tinguished from the base of the bladder on rectal palpation, but when diseased, as in tuberculous 

 or gonorrhoeal vesiculitis, are enlarged and indurated and can be detected readily. 



The ejaculatory ducts, formed by the union of the vesicular and deferential duct of each 

 side, are 2-2.5 cm. in length. The first few millimeters of their course is extra-prostatic, and 

 then entering the posterior surface of the prostate they run side by side downward and forward 

 through the gland, close to the middle line, to open into the urethra on the coUiculus seminalis 

 at either side of the opening of the prostatic sinus. It is by these little ducts that infection 

 travels from the urethra to the vesiculae and epididymis in gonorrhoea. 



Descent of the testis. — The testis is developed between the tenth and twelfth thoracic 

 segments of the embryo, and subsequentlj^ moves downward. By the third month of intra- 

 uterine life it descends into the iliac fossa; from the fourth to the seventh month it hes at the 

 abdominal inguinal ring; during the seventh month it passes obliquely through the abdominal 

 wall by the inguinal canal; by the eighth month it lies at the subcutaneous inguinal ring, and it 

 reaches the fundus of the scrotum about the time of birth. The left testis is slightly earlier 

 than the right in all these stages. The descent referred to is due in part to the common descent 

 of organs, associated with the descent of the diaphragm, but mainly to the gubernaculum. This 

 is a mass of fibro-muscular tissue that forms under the inguinal fold (or plica gubernatrix) of 

 peritoneum below the testis as it lies in the iliac fossa, and in the mesorchium. It grows down 

 obliquely through the abdominal wall from a point lateral to the inferior epigastric artery, and 

 tunnels out a passage for the testis. As it travels down into the scrotum it carries in front of 

 it three layers of investing fascia derived from the abdominal wall, viz., external spermatic 

 fascia from the external oblique, cremasteric from internal oblique and transversus muscles, 

 and infundibuliform fascia from the transversalis fascia. The gubernaculum is attached above 

 to the peritoneum and the posterior aspect of the testis, and by its subsequent contraction it 

 draws down into the scrotum first a diverticulum of peritoneum, the processus vaginalis, and 

 secondly the testis, which projects into the processus from behind just as it did into the 

 coelom. 



Shortly after birth, obliteration of the processus vaginalis should occur, commencing at 

 the deep abdominal ring and immediately above the testis. The part of the processus between 

 these two points disappears completely. The lowest part, surrounding the testis, persists as 

 the tunica vaginalis. Failure of obliteration, if complete, leaves a congenital hernial sac; if 



