Perineum - LO 12

12. Diagram the branches of the internal pudendal artery.

The internal pudendal a. is one of the terminal branches of the anterior division of the internal iliac a. It exits the pelvis through the greater sciatic foramen, and then enters the ischio-anal fossa via the lesser sciatic foramen and pudendal canal. 

The internal pudendal a. is the primary source of blood to the skin, muscles, and erectile bodies of the perineum. The external pudendal a., a branch of the femoral a., also supplies portions of the anterior perineum.

Branches of the internal pudendal a. include:

• • Inferior rectal (anal) aa.

    • • Branching point: proximal portion of pudendal (Alcock's) canal

      • Supplies: external anal sphincter

  • Perineal aa.

    • • Branching point: distal portion of pudendal (Alcock's) canal

      • Supplies: ischiocavernosus mm., bulbocavernosus mm., skin and subcutaneous layer of the perineum (and labia majora in females/ scrotum in males)

      • Branches:

        • • Posterior labial/posterior scrotal aa.: supply to labia majora and minora/posterior scrotum

          • Artery of vestibule/bulb of penis: supply to corpus spongiosum (bulb of vestibule and penis; greater vestibular gland (female); bulbo-urethral gland (male)

  • Deep aa. of clitoris/penis: 

    • • Branching point: a terminal branch of internal pudendal a.; through perineal membrane and tunica albuginea

      • Supplies: corpora cavernosa through helicine and straight artery branches

  • Dorsal aa. of clitoris/penis: 

    • • Branching point: a terminal branch of internal pudendal a. that is located on posterior portion of clitoris/penis 

      • Supplies: superficial tissues of the clitoris/penis; deep perineal pouch

The internal pudendal vv. receive blood from the deep vv. of the clitoris / penis, dorsal vv. of the clitoris / penis, v. of the bulb, perineal v., and inferior rectal v. Typically, the pudendal vv. are venae comitantes of the internal pudendal a. that coalesce as a single internal pudendal v. that travels through the pudendal (Alcock's) canal to join the internal iliac v.