Lecture Notes - Perineum & External Genitalia

Perineum - inferior to pelvic diaphragm

• Anal Triangle
  • ischioanal fossae - lateral to anal canal
    • obturator internus muscle is lateral wall
  • pudendal canal - fascia of obturator internus muscle
    • contains internal pudendal vessels & pudendal nerve
  • anal canal - review anal canal - internal structures and sphincter muscles
• Urogenital Triangle
  • Perineal Membrane - bands of connective tissue between midline viscera and ischiopubic rami; erectile tissues attached to caudal surface

Female	Male
2 corpora cavernosa shaft of clitoris diverge as 2 crura along ischiopubic rami crura covered by ischiocavernosus muscle	2 corpora cavernosa shaft of penis diverges as 2 crura crura covered by ischiocavernosus m.
2 bulbs of the vestibule glans of clitoris covered by bulbospongiosus m. greater vestibular glands	1 corpus spongiosus glans of penis spongy urethra bulb covered by bulbospongiosus m.
perineal body muscle fibers from: bulbospongiosus, external anal sphincter & superficial transverse perineal	central tendinous point mm. fibers from: bulbospongiosus, ext. anal sphincter & superficial transverse perineal
sphincter urethrae (urethrovaginal sphincter & compressor urethrae)	sphincter urethrae bulbourethral glands

Pudendal Nerve

• motor to all perineal muscles and sensory to most perineal structures
• 3 branches
  • inferior rectal - external anal sphincter and skin around anus
  • perineal - posterior labial/scrotal branches
  • dorsal nerve of clitoris/penis - remainder of pudendal; within connective tissue of perineal membrane; pierces membrane at anterior border and runs with dorsal aa. and v.

Internal Pudendal Artery

• 3 branches
  • inferior rectal - anastomoses with which vessels?
  • perineal - superficial; terminates as posterior labial/scrotal
  • internal pudendal - runs deep with dorsal n. of clitoris/penis
    • 2 terminal branches
      • deep artery of clitoris/penis - within corpora cavernosa
      • dorsal artery of clitoris/penis - with nerves and vein