THE VAS DEFERENS. 1107 
where it breaks up into branches which enter the mediastinum testis, and are distributed alone 
the septa and on the deep surface of the tunica albuginea. The veins issuing from the po sterior 
border of the testis form a dense plexus, called the plexus pampiniformis, which finally pours its 
blood through the spermatic vein, on the right side, into the inferior vena cava: on the left side 
into the left renal vein. The nerves for the testis accompany the spermatic artery and are derived 
from the aortic and renal plexuses. The arteries and nerves of the testis commannneane with 
those on the lower part of the vas deferens, namely, with the artery of the vas and with twigs 
from the hypogastric plexus. The lymphatic vessels of the testis pass upwards in the spermatic 
cord, and end in the lumbar lymphatic glands. 
THE VAS -DEFERENS. 
The vas deferens (ductus deferens) is the direct continuation of the eanal of the 
epididymis. Beginning at the lower extremity of the epididymis, it ends, after a 
course of nearly 18 inches, by opening as the common ejaculatory duct into the 
prostatic or first part of the urethra. The duct in parts of its course is somewhat 
convoluted, and the actual distance traversed by it is not more than 12 inches. 
Placed in the first instance outside the abdominal cavity, the vas deferens ascends 
within the scrotum towards the lower part of the anterior abdominal wall, which it 
reaches not far from the middle line. During this part of its course the duct, 
together with the vessels and nerves of the testis, is surrounded by a number of 
loose coverings derived from certain layers of the abdominal wall, and the cord-like 
structure so formed is termed the spermatic cord. The vas deferens, together with 
the accompanying vessels and nerves, now passes through the abdominal wall in an 
oblique passage, to which the name inguinal canal is applied. Within the abdomen 
the vas hes immediately beneath the peritoneum, and soon crossing over the pelvic 
brim, it enters the pelvis, on the side wall of which it proceeds backwards towards 
the base of the bladder. Here, near the middle line, the vas deferens is joined by 
the duct of the corresponding vesicula seminalis, and the common ejaculatory duct, 
thus formed, having traversed the prostate, opens into the urethra. 
At first the vas deferens, like the canal from which it takes its origin, is very 
tortuous, but soon increasing in thickness, the duct becomes less twisted, and passes 
upwards along the inner side of the epididymis and behind the testis to enter the 
spermatic cord (Fig. 752). Its course is now almost vertically upwards towards 
the spine of the pubis, near which, crossing the inner part of Poupart’s ligament, 
the vas enters the inguinal canal by the external abdominal ring. Of the structures 
composing the spermatic cord the vas is the most posterior, and it can be readily 
distinguished, even in the undissected subject, by its hard firm feel when it is taken 
between the finger and thumb. In the inguinal canal the vas is directed outwards, 
upwards, and a little backwards to the internal abdominal ring, where, at a point 
half-an-inch above Poupart’s igament, and midway between the symphysis pubis 
and the anterior superior iliac spine, it enters the abdomen. The distance between 
the point where the cord enters the inguinal canal to the point where it leaves it 
to enter the abdomen is about one and a half inches. While passing from the 
external to the internal abdominal ring the vas deferens, together with the other 
structures of the spermatic cord, rests upon the upper grooved surface of Poupart’s 
ligament, and is placed behind the aponeurosis of the external oblique and some of 
the lower fibres of the internal oblique muscle. From before backwards the vas 
rests, in the first instance, upon the conjoimed tendon of the internal oblique and 
transversalis muscles, and further outwards upon the transversalis fascia. Above the 
cord are some arching fibres of the internal oblique muscle, which enter the conjoined 
tendon. As the vas deferens leaves the inguinal canal by the internal abdominal 
ring, it turns round the deep epigastric artery on its outer and posterior aspect. 
Completely changing the direction of its course, the duct now runs for a short 
distance backwards, inwards, and upwards, beneath the peritoneum to a point one and 
a half to two inches from the spine of the pubis, where it crosses the ilio-pectineal 
line and enters the pelvis. In this part of its course the duct usually at first hes in 
front of the external iliac vessels, and then in the floor of a little triangular fossa 
between the vessels and the pelvic brim. On the side wall of the pelvis the vas is 
continued backwards, and a little downwards and inwards, in the direction of the 
ischial spine, and lies immediately beneath the peritoneum, through which it ean 
