Vas deferens

Function

The vas deferens is the sperm's muscular highway — a 45 cm tube whose thick smooth-muscle wall whips sperm forward in peristaltic pulses during ejaculation. From the epididymal tail it climbs the spermatic cord, passes through the inguinal canal, hooks around the inferior epigastric artery at the deep ring, crosses over the ureter to the bladder's base and joins the seminal vesicle's duct to form the ejaculatory duct entering the prostate.

Its deliberate division — vasectomy — is one of the most reliable forms of contraception, sometimes reversible by microsurgical reanastomosis.

Blood supply

Artery to the vas (from the inferior vesical).

Nerve supply

Sympathetic L1–L2 — ejaculation's rhythmic contraction.

Clinical relevance

Vasectomy

Division of the vas — 15-minute surgery, lifelong effect; post-vasectomy pain syndrome is its rare, stubborn complication.

Congenital absence

CFTR gene mutations can cause congenital absence of the vas — men present with obstructive azoospermia.

Related conditions

• Male infertility