Pelvis (sem 4)

Question 1

what nerves run down the sacral hiatus/canal

Answer 1

coccygeal nerve

4th sacral nerve

Question 2

what level does the spinal cord / dura mater terminate

Answer 2

spinal cord ends at L2/3

then continues as cauda equina (lumbar puncture from here)

dura mater ends at S2 (as it protects cauda equina)

Question 3

what nerve and artery wind around the ischial spine

Answer 3

pudendal nerve

internal pudendal artery

Question 4

2 structures that exit greater foramen ABOVE piriformis

Answer 4

superior gluteal vessels (artery + vein)

superior gluteal nerve

Question 5

6 nerves and 2 arteries that leave the greater foramen BELOW piriformis

Answer 5

nerves

• sciatic (deep to piriformis)
• pudendal
• inferior gluteal nerve
• nerve to posterior femoral cutaneous
• nerve to obturator internis
• nerve to quadrates femoris

arteries

• inferior gluteal
• internal pudendal

Question 6

Alcock’s canal (pudendal canal) + structures that enter

Answer 6

canal within the obturator fascia = medial surface of obturator internus

• internal pudendal artery/vein
• nerve to obturator internus
• pudendal nerve

Question 7

the one structure that leaves the pelvis via LESSER sciatic notch

Answer 7

obturator internus muscle (inserts into greater trochanter - above where the externus inserts)

Question 8

levator ani muscles + innervation (+ what if this is damaged)

Answer 8

inferior rectal branch of pudendal nerve S2-4
+ Branches direct from the ventral ramus of S4

(damage to nerve = incontinence + organ prolapse)

• puborectalis
• pubococcygeus
• iliococcygeus

Question 9

commonest cause that damages the pelvic floor

Answer 9

vaginal child birth

Question 10

6 structures that contribute to the perineal body

Answer 10

• Levator ani
• External anal sphincter
• External urethral sphincter
• Deep transverse muscle
• Superficial transverse muscle
• Bulbospongious muscle

Question 11

6 structures that contribute to the perineal body

Answer 11

• Levator ani
• External anal sphincter
• urethrovaginalis sphincter (female)
• Deep transverse muscle
• Superficial transverse perineal muscles
• Bulbospongious muscle

Question 12

sacrum:

• ala
• promontory

Answer 12

ala = inward protruding large triangular surface either side of sacral base

promontory= anterior part of the body of the first sacral vertebra

Question 13

How do you differentiate between a male and a female pelvis?

Answer 13

pelvic inlet

women = circular "gynaecoid" (due to less distinct promontory and broader ala)
men = heart shaped "anthropoid"

pubic angle is wider in women

Question 14

How is the pelvis orientated in the anatomical position?

Answer 14

pubic tubercle and ASIS are in the same vertical line

Question 15

4 types of pelvis (shape)

Answer 15

gynaecoid
anthropoid
android
platypelloid

Question 16

pudendal nerve roots

Answer 16

S2,3,4

Question 17

pudendal nerve course

Answer 17

S2,3,4
out of greater foramen inferior to piriformis
around the sacrospinous ligament
enters the anal triangle of perineum by passing medially through the lesser foramen
through the lateral wall of ischiocanal via the pudendal canal

Question 18

coccygeus muscle

Answer 18

origin = sacrospinous ligament + ischial spine

insertion = lateral margin of coccyx

action = pulls coccyx forwards after defecation

Question 19

perineum

Answer 19

a diamond shaped space forming the outlet of the pelvis

(coccyx, pubic symphysis, ischial tuberosities)

divided by the ischial tuberosities into

• urogenital triangle
• anal triangle

Question 20

perineal membrane

Answer 20

covers the anterior U shape space (urogenital hiatus)

separates the deep perineal pouch from the superficial

Question 21

contents of the deep perineal pouch

Answer 21

female

• external urethral sphincter
• compressor urethrae
• sphincter urethrovaginalis
• deep transverse perineal muscles
• skenes glands

male

• external urethral sphincter
• deep transverse perineal muscles
• bulbourethral glands

Question 22

structures in the superficial perineal pouch

Answer 22

male

• crus of penis (attached to corpus cavernosum)
• bulb of penis
• ischiocavernous muscle
• bulbospongiosus muscle
• perineal body
• superficial transverse perineal muscle

female

• crus of clitoris (attached part of corpus cavernosum)
• bulb of vestibule
• greater vestibular gland(bartholin’s)
• ischiocavernous muscle
• bulbospongiosus muscle
• perineal body
• superficial transverse perineal muscle