674 ^ MANUAL OF ANATOMY 



paring this path for the testis, its gubernaculum takes with it the parietal 

 peritoneum forming the peritoneal depressioh, just alluded to, which accord- 

 ingly constitutes a peritoneal process, called the processus vaginalis. This 

 process may be likened to the finger of a glove, being open towards the peri- 

 toneal or abdominal cavity, but closed at its distal end. The principal part 

 of the gubernaculum lies behind the processus vaginalis, which latter aids the 

 stout gubernaculum in the formation of the inguinal canal. 



As the processus vaginalis penetrates the inguinal portion of the abdominal 

 wall, it elongates before it the several elements which compose the wall, in the 

 following order from within outwards : 



1. Subperitoneal areolar tissue. 



2. Fascia trans versalis. 



3. Lowermost Poupart fibres of internal oblique muscle (cremaster). 



4. External oblique aponeurosis. 



5. Scarpa's and Camper's fasciae (tunica dartos). 



6. Skin of scrotum. 



In the foregoing manner the internal abdominal ring, inguinal canal, and 

 external abdominal ring are formed by the gubernaculum testis and pro- 

 cessus vaginalis. Beyond the external abdominal ring these two structures 

 enter the corresponding scrotal chamber, the lower part of the processus 

 vaginalis forming a serous lining for it. The lower part of the gubernaculum 

 extends lower down than the lower end at the processus vaginalis, and this 

 portion is attached to the fundus of the scrotal chamber. 



The intraparietal stage in the migration of the testis consists in the passage 

 of the organ through the inguinal canal. This stage commences about the 

 seventh month of intra-uterine life, and the testis follows the lead of the 

 middle or principal bundle of the gubernaculum testis, gliding along the 

 posterior wall of the processus vaginalis, and being post-vaginal in position. 



The scrotal stage consists in the entrance of the testis into the corresponding 

 scrotal chamber, which usually takes place about the end of the eighth 

 month of intra-uterine life. The organ still lies behind the lower part of the 

 processus vaginalis, which it invaginates from behind, to form the tunica 

 vaginalis. The middle or principal bundle of the gubernaculum testis has 

 now become very short, and is ultimately represented by an indefinite fibrous 

 bundle, spoken of as the remnant of the gubsinaculum, which connects the 

 lower parts of the epididymis and testis to the fundus of the scrotal chamber. 



As the testis descends into the scrotum, the outer or Poupart and inner 

 or pubic bundles of the gubernaculum testis, according to the view that there 

 is a conus inguinalis, are drawn downwards on the sides of the spermatic 

 cord. 



There are two theories regarding the migration of the testis, which may be 

 called developmental and muscular. According to the developmental theory 

 the migration is not an active process, due to muscular contraction, but is 

 brought about by developmental changes, of the nature of disproportionate 

 or unequal growth, which take place in the lumbar, iliac, and inguinal regions 

 of the trunk. According to the muscular theory, maintained by those who 

 favour the existence of a conus inguinalis, the migration is brought about by 

 muscular contraction, as follows: All three bundles of the muscular inguinal 

 cone would draw the testis down to the inguino-pubic region, and thereafter 

 the middle bundle would draw it down into the scrotal chamber, the outer 

 and inner bundles being elongated downwards. The non-striated muscular 

 fibres in the core of the gubernaculum may also take part in the descent, 

 and the descent may be aided by the ' retraction ' of the connective tissue 

 of the gubernacular core. 



Metamorphoses of the foregoing Peritoneal Folds — Male. — The plica guber- 

 natrix or plica inguinalis in the male contains the gubernaculum testis. The 

 inferior testicular fold forms part of the plica gubernatrix. The superior 

 testicular fold or plica vascularis contains the elements of the- spermatic cord. 

 The mesorchium, derived from the greatly reduced urogenital nleL^cnte^y, 

 connects the testis and epididymis. 



