The vas deferens are two muscular tubes that transport sperm from the epididymis to the ejaculatory duct. Each vas deferens begins at the testis and ascends behind the testis and epididymis into the spermatic cord. It then passes through the inguinal canal into the abdomen and loops around blood vessels in the pelvis before joining the seminal vesicle duct to form the ejaculatory duct. A vasectomy involves cutting and sealing a short segment of each vas deferens to prevent sperm from being ejaculated and cause male sterilization.

1. VASA DEFERENTIA
(DEFERENT DUCTS)
By Dr. Vibhash kumar Vaidya

2. VASA DEFERENTIA (DEFERENT DUCTS)
 These are two in number (right and left).
 Each vas deferens is a thick-walled muscular tube
which transports spermatozoa from the epididymis
to the ejaculatory duct.
 The vas deferens is about 18 inches (45 cm) long
and has a narrow lumen except in the terminal part
which is sacculated—the ampulla of vas deferens.

4. COURSE AND RELATIONS
External Course of Vas Deferens-
 It begins at the inferior pole of the testis as direct
continuation of the duct of epididymis and ascends upward
behind the testis and medial to the epididymis.
 It enters the spermatic cord, where it lies in its posterior
part, which is the usual site of vasectomy.
 It passes through inguinal canal and enters the abdominal
cavity by passing through the deep inguinal ring located
lateral to the inferior epigastric artery.

5. Internal Course of Vas Deferens-
 It hooks around the lateral side of the inferior epigastric artery and passes backward and
medially across the external iliac vessels and enters the lesser pelvis.
 In the lesser pelvis, it runs downward and backward on the lateral pelvic wall crossing
successively obliterated umbilical artery, obturator nerve, and vessels.
 Then it crosses above and medial to the terminal part of the ureter and makes an angular bend
downward and medially.
 Thereafter, it passes behind the base of the bladder in front of the rectal ampulla and on the
medial side of the seminal vesicle.
 This part of the vas deferens is enlarged and sacculated to form an ampulla which probably
stores the semen.
 Finally it reach the base of prostate where it joins the duct of the seminal vesicle to form the
ejaculatory duct.

6. ARTERIAL SUPPLY-
1. Artery to vas deferens, a branch of superior vesical artery.
2. Artery to vas deferens, a branch of inferior vesical artery.
3. Artery to vas deferens, a branch of middle rectal artery.
VENOUS DRAINAGE-
The veins from vas deferens join the vesical venous plexus which in turn drains into the
internal iliac veins.
NERVE SUPPLY-
It is primarily by the parasympathetic fibres from the pelvic splanchnic nerves.

7. Clinical correlation
Vasectomy:
 This is a common method of male
sterilization.
 It is a minor operation done under local
anesthesia.
 In this procedure, a short segment of
each vas is cut.
 The cut ends are crushed and ligated.
 As a result, seminal fluid ejaculated a
week after vasectomy, will not contain
sperms and hence pregnancy cannot
occur.