Perineum

Question 1

What does the labia major contain?

What is the clinical significance?

Answer 1

• Terminal end of round ligament - can give rise to leiomyomas
• Terminal end of processes vaginalis (canal of nuck) - if remains patent can give rise to indirect inguinal hernia

Question 2

What are the borders of the anterior triangle?

Answer 2

Pubic rami

Ischial tuberosity

superficial and deep transverse perineal muscles

Perineal body

Question 3

What are the borders of the posterior triangle?

Answer 3

superficial and deep transverse perineal muscles

Perineal body

Ischial tuberosities

Inferior border gluteus maximus

Coccyx

Question 4

What is in the superficial perineal pouch/compartment of anterior triangle?

Answer 4

Superficial to perineal membrane

• Bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles
• Glans and crura of clitoris
• vestibular bulbs

Question 5

What is the innervation of the perineum?

Answer 5

• S2-4
• Pudendal nerve
  
  • dorsal nerve of clitorus
  • perineal nerve
  • inferior rectal nerve

Question 6

What is the course of the pudendal nerve?

Answer 6

• S2-4 sacral plexus
• exits pelvis through greater sciatic foramen, courses around sacrosponous ligament and enters deep perineal pouch through lesser sciatic foramen, where it passes over obturator internus muscle contained in the pudendal (alcocks) canal
• It splits to give rise to inferior rectal nerve (to external anal sphincter), perineal nerve (perineum), dorsal nerve of clitorus (courses anteriorly adjacent to ischiopubic rams in deep perineal such, then perforates perineal membrane to enter superficial perineal pouch and then courses on deep surface ischiocavernosus and crus of clitoris)

Question 7

What is the role of pudendal nerve?

Answer 7

Innervates superficial perineal muscles

Sensation of perineam

Innervates striated parts of external urethral and anal sphincters

Question 8

What are the muscles of the pelvic diaphragm?

Answer 8

Levator ani:

• Pubococcygeus
• Ichiococcygeus
• (iliococcygeus) coccygeus

Puborectalis

Question 9

What are the attachments of levator ani?

Answer 9

origins

• pubic rami
• tendinous arch of levator ani / white line

insertions

• lateral vagina
• perineal body
• external anal sphincter
• coccyx
• ano-coccygeal raphe