DESCENT OF THE TESTIS. a i 
Vessels and Nerves of the Vas and Vesicula Seminalis.—The vas receives its arterial 
supply from the superior or inferior vesical arteries. The artery to the vas accompanies that 
structure, supplying it as far as the testis, where it ends by anastomosine with branches of the 
spermatic artery. The vesicula seminalis is supplied by the inferior vesical artery The nerves 
of the vas and vesicula seminalis are derived from the hypogastric plexus. A oa 
DESCENT OF THE TESTIS. 
The peculiar course pursued by the vas deferens in the adult, and the manner in which 
it is related to the anterior abdominal wall, are rendered clear by a study of the arrange- 
ment of the parts that obtains in the foetus. The testes until nearly the end of intra- 
uterine life are placed in the abdominal cavity. Lying at first on the posterior wall 
of the abdomen, in the neighbourhood of the kidney, the testis is held in place by 
a fold of peritoneum, which forms for it a mesentery called the mesorchium. As srowth 
goes on the testis is found to occupy a lower level in the abdominal cavity, and in 
the seventh month it lies near the internal abdominal ring. Meanwhile a blind pouch 
or diverticulum of the peritoneal membrane, termed the processus vaginalis, has grown 
downwards and inwards 7 
through the anterior Bee eee ey, 
abdominal wall towards the Seiad cine : : 
scrotum, deriving as it goes 
a covering from each of the 
layers of the abdominal wall 
through which it passes. 
The testis with its mesor- j by 
chium enters the diverti- Fa /) peau S777 fll] 
culum of the abdominal deferens \ hwy an / ee Tipe 07 +~Mesorchium 
cavity, and in this manner i Vie pi 
reaches the scrotum. Ata 
later stage, the connexion Xe Yip Sa NZ Td] See 
between the part of the . | if / ms 
processus vaginalis that les 
in the scrotum and the 
peritoneal lining of the 
abdomen becomes lost by waa Aare b 
: aie I . ‘iG. 757.—VIEW LOOKING FROM ABOVE INTO THE ELVIS AND LOWER 
the:obliteration of the led ae Part OF THE ABDOMINAL CAVITY IN A F@TUS OF ABOUT THE 
part of the pouch. Thus SevenTH MoNtTH. 
the part of the PYOcessUS On the left side, which represents a slightly more advanced condition than 
vaginalis that persists in the right, the testis has entered the inguinal canal; on the right side 
the scrotum becomes the the testis is still within the abdominal cavity. 
parietal portion of the 
tunica vaginalis ; while the visceral part of that membrane is the primitive peritoneal 
covering of the testis and epididymis (Figs. 757 and 758). 
Often 2a small fibrous band-—the ligamentum vaginale—may be found in the adult 
passing through the inguinal canal and joining the peritoneum superiorly in the region of 
the internal abdominal ring. Sometimes 
the ligament is connected below with the 
tunica vaginalis, but more often it does 
not reach so far downwards. 
When present it represents the obliter- 
ated portion of the processus vaginalis 
(rudimentum processus vaginalis). In 
other rare cases the processus vaginalis 
may persist after birth as a channel freely 
Fic. 758. —Dracram to illustrate the descent of the OP? to the abdominal cavity above, or 
testis and the manner in which the tunica vaginalis the passage, becoming closed at intervals, 
Epididymis 
Gubernaculum 
ape 
‘ af ~~ , 
Gf ~Vas deferens 
Psoas 
Rectum 
is derived. may give rise to one or more cysts within 
a.c. Abdominal cavity. s. Scrotum. the coverings of the spermatic cord. 
p.v. Processus vaginalis. t.v. Tunica vaginalis. Sears 
me leche: - z, Ligamentum vaginale. It sometimes happens that the descent 
of the testis is arrested, and then, either 
failing to enter the processus vaginalis, the testis remains within the abdominal cavity ; 
or entering the processus vaginalis, it fails to reach the scrotum, and lies in the inguinal 
canal. The term cryptorchism is frequently applied to such cases. 
In connexion with the descent of the testis a remarkable cord-like structure—the 
