Perineum

Question 1

Describe the course of the internal pudendal artery and pudendal nerve in the pelvis and
perineum

Answer 1

• Internal pudendal a. from Internal Iliac a. Anterior division
• Pudendal n. from S2, S3, S3
• Both leaves Pelvic cavity through Greater Sciatic foramen and then immediately enters perineum inferiorly to pelvic floor by passing through Lesser Sciatic foramen.
  
  • Enters pudendal canal at lesser sciatic notch
  • Supplies perineum
  • Levator ani
  • Scrotum (Post. Scrotal n., branches of Perineal Branch of Pudendal n.)
  • Vagina & Uterus (Deep perineal n.)
  • External anal sphincter (I. Anal n.)
  • Bulbospongiosus & Ischiocavernous (Muscular deep branch of perineal n.)
  • Deep Transverse Perineal (Muscular deep branch of perineal n.)
  • External Urethral Sphincter (Muscular deep branch of perineal n.)
  • Vulva (central part by pudendal n.)

Question 2

Bony landmarks used for determinnig position of pudendal n for transvaginal pudendal n. block and list the areas anaesthetized

Answer 2

Pudendal nerve block important aneaesthesia in childbirth & pelvic surgery

• pudendal n. crosses lateral sacrospinous ligament
• Also need to block Ilioinguinal n. for anterior to abolish pain from anterior perineum
• Palpate Ischial spine with fingers in vagina
• Stay medial to ischial spine with needle to avoid Sciatic n.

Question 3

List boundaries of the Superficial Perineal Pouch

Answer 3

• Area b/w
  
  • Perineal membrane
  • Superficial Perineal Fascia
• Deep Perineal Fascia covers the Superficial Perineal m.

Question 4

Contents of Superficial Perineal Pouch

Answer 4

Male

• Bulb of penis
• Crus of penis
• Ischiocavernous m.
• Bulbospongiosus m.
• Superficial transverse perineal m.
• Perineal branches of pudendal n.
• Internal pudendal vessels

Female

• Crura of clitoris
• Bulb of vestibule
• Urethra
• Vagina
• Greater vestibular glands
• Bulbospongiosus m.
• Ischiocavernous m.
• Superficial transverse perineal m.
• Perineal branches of pudendal n.
• Perineal branches of internal pudendal vessels

Question 5

Compare & contrast the areas into which urine can extravasate following an Intrapelvic vs. Extrapelvic Rupture of Urethra

Answer 5

• IntraPelvic: junction b/w prostatic and membranous parts of urethra - usually caused by pelvic fracture and resulting in extravasation of urine into pelvis and disruption of the prostate if the puboprostatic ligaments are damaged
• ExtraPelvic aka Straddle Injury: Bulbous portion of penile part of urethra
  
  • usually caused when structures of perineum are caught b/w a hard object and inferior pubic arch

Question 6

Explain why extravasated urine will not pass into things or the Ischioanal Fossa

Answer 6

• Extravasated urine in body of penis only and contained within Buck’s fascia
• Will not pass into:
  
  • thigh
  • ischioanal fossa
• This means that fluids or infectious material that accumulate in Superficial Perineal Pouch can track out of perineum and into ant. ab wall but not to the anal triangle or the legs because the Superficial Fascia of the Perineum fuses with the deep tissues at the border with these regions.