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Magill’s Medical Guide, 9th Edition

Vas deferens

by Roger Smith, , PhD

Category: Anatomy

Also known as: Ductus deferens

Anatomy or system affected: Genitals, reproductive system

Specialties and related fields: Urology

Definition: The tube that conveys sperm from the epididymis to the urethra in the male reproductive system.

STRUCTURE AND FUNCTIONS

In the male reproductive system, the testes make sperm, which is then stored in an adjacent structure, the epididymis. The epididymis is connected to the urethra via the vas deferens (plural, vasa deferentia), a smooth tube about 18 inches (45 centimeters) in length with thick, muscular walls that forms part of the spermatic cord along with various nerves, muscles, and blood vessels.

A male has two vasa deferentia. From the epididymis, located to the rear of each testis, a vas deferens leads up into the abdominal cavity through the inguinal canal (a passageway through the abdominal wall). It curves around behind the bladder and, via an enlargement called the ampulla, merges with the seminal vesicle near the base of the bladder. From there it passes through the prostate gland into the urethra.

During sexual intercourse, the walls of the vas deferens contract to move sperm out of the epididymis. The sperm mixes with seminal fluids from the seminal vesicle, prostate gland, and bulbourethral glands (Cowper’s glands). The ampulla and duct of the seminal vesicle together are the ejaculatory duct through which sperm is propelled into the urethra for ejaculation from the penis.

DISORDERS AND DISEASES

Congenital defects of the male reproductive system that cause infertility include malformation or absence of one or both of the vasa deferentia. The exact mechanisms behind the defects are unknown, although there is a correlation with the genetic markers for cystic fibrosis. Obstructions in the vas deferens also occur, or an inguinal hernia may pinch it.

A principal means of contraception by sterilizing men involves the vas deferens. This is the vasectomy (also, deferentectomy), in which the vasa deferentia are either cut and sealed, clipped, or injected with a material to block them. Urologists perform the procedure, usually during an office visit, and it takes about twenty minutes. Possible complications include reduced sexual desire, bleeding, inflammation, sperm leakage, and spontaneous reopening. Postvasectomy pain syndrome is a condition of chronic pain in some men because of pressure, inflammation, or physical changes in the vas deferens. In some cases, a vasectomy can be reversed surgically so that the man is again fertile.

See also Conception; Contraception; Erectile dysfunction; Genital disorders, male; Glands; Infertility, male; Masturbation; Men’s health; Orchitis; Penile implant surgery; Prostate cancer; Prostate enlargement; Prostate gland; Prostate gland removal; Puberty and adolescence; Reproductive system; Semen; Sexual dysfunction; Sexuality; Sexually transmitted diseases (STDs); Sterilization; Testicles, undescended; Testicular cancer; Testicular surgery; Testicular torsion; Vasectomy.

For Further Information:

1 

Beers, Mark H., ed. The Merck Manual of Medical Information. 2d ed. Whitehouse Station, N.J.: Merck Research Laboratories, 2003.

2 

Denniston, George C. Vasectomy. Victoria, BC: Trafford, 2002.

3 

Parker, Steve. The Human Body Book. New York: DK Adult, 2001.

4 

Thibodeau, Gary A., and Kevin T. Patton. Structure and Function of the Body. 14th ed. St. Louis: Mosby/Elsevier, 2012.

5 

“Vasectomy.” Urology Care Foundation, January 2011.

Citation Types

Type
Format
MLA 9th
Smith, Roger. "Vas Deferens." Magill’s Medical Guide, 9th Edition, edited by Anubhav Agarwal,, Salem Press, 2022. Salem Online, online.salempress.com/articleDetails.do?articleName=MMG2022_1436.
APA 7th
Smith, R. (2022). Vas deferens. In A. Agarwal, (Ed.), Magill’s Medical Guide, 9th Edition. Salem Press. online.salempress.com.
CMOS 17th
Smith, Roger. "Vas Deferens." Edited by Anubhav Agarwal,. Magill’s Medical Guide, 9th Edition. Hackensack: Salem Press, 2022. Accessed October 22, 2025. online.salempress.com.