Veterinary Andrology and Reproductive Techniques

SCROTUM

Scrotum

• The scrotum is a bi-lobed sac or pouch (derived from the skin and fascia) and is the external part of male reproductive system which encloses the testis.
• It is located between the thighs except in case of boar and tom cat.
• In boar and tom cat, it is located caudal to the thighs, caudal and ventral to the ischiatic arch.
• Scrotum externally composed of skin which is relatively devoid of hair except in ram (male sheep) and buck (male goat) and tom cat (male cat).

• Beneath the skin is the dartos muscle, which consists of fibroelastic tissue and unstripped muscle.
• Dartos muscle divides the scrotum in to two halves.
• It is closely attached with the tunica vaginalis and scrotal ligament which is a remnant of gubernaculum. Scrotal ligament is absent in bulls.
• Testis and epididymis are fixed in scrotum by means of scrotal ligament which is attached near the tail of the epididymis and mesorchium. (Click here to view animation)

TOP

LOCATION OF SCROTUM IN DIFFERENT SPECIES
Scrotum in bull located between thighs	Scrotum in stallion located between thighs
Scrotum in buck located between thighs	Scrotum in ram located between thighs
Scrotum in dog located between thighs	Scrotum in boar is located caudal to the thighs, caudal and ventral to the ischiatic arch
Scrotum in tom cat is located caudal to the thighs, caudal and ventral to the ischiatic arch

TOP

Scrotum has the following 8 layers from externally

Epidermis – outermost layer Dermis Dartos muscle Connective tissue Parietal layer of vaginal process (PVP) Cavity of vaginal process (CV) Visceral layer of vaginal process (VVP) Tunica albuginea

• Tunica albuginea penetrate the testicular parenchyma to join at mediastinum.
• These fibrous septa divide the testicular parenchyma into lobules.
• The lobules are having the highly coiled seminiferous tubules.
• About 75% of the testicular mass is composed of seminiferous tubules.

Scrotum, cremaster muscle and pampiniform plexus maintains the testicular temperature

TOP

Functions

• It encloses the male gonad
• It provides suspensory attachment of testes with remaining animal body.
• It protects the testes from adverse stress conditions.
• It serves as a thermic chest of male gonad.
• It maintains gonadal temperature through thermo regulatory mechanism for optimum spermatogenesis.

The scrotum becomes flaccid and elongated due to relaxation of the dartos and cremaster muscle, under hot climate. It becomes contracted and wrinkled during cold climate

Blood supply

• External pudental artery and also Internal pudental artery in boar and cat

Nerve supply

• Genital nerve which is a branch of genito-femoral nerve arising from second to fourth lumbar nerve and perineal nerve.
• Smooth muscle of the scrotum is supplied by the spermatic plexus from pelvic plexus.

TOP