Pelvis (sem 4) Flashcards
what nerves run down the sacral hiatus/canal
coccygeal nerve
4th sacral nerve
what level does the spinal cord / dura mater terminate
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)
what nerve and artery wind around the ischial spine
pudendal nerve
internal pudendal artery
2 structures that exit greater foramen ABOVE piriformis
superior gluteal vessels (artery + vein)
superior gluteal nerve
6 nerves and 2 arteries that leave the greater foramen BELOW piriformis
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
Alcock’s canal (pudendal canal) + structures that enter
canal within the obturator fascia = medial surface of obturator internus
- internal pudendal artery/vein
- nerve to obturator internus
- pudendal nerve
the one structure that leaves the pelvis via LESSER sciatic notch
obturator internus muscle (inserts into greater trochanter - above where the externus inserts)
levator ani muscles + innervation (+ what if this is damaged)
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
commonest cause that damages the pelvic floor
vaginal child birth
6 structures that contribute to the perineal body
- Levator ani
- External anal sphincter
- External urethral sphincter
- Deep transverse muscle
- Superficial transverse muscle
- Bulbospongious muscle
6 structures that contribute to the perineal body
- Levator ani
- External anal sphincter
- urethrovaginalis sphincter (female)
- Deep transverse muscle
- Superficial transverse perineal muscles
- Bulbospongious muscle
sacrum:
- ala
- promontory
ala = inward protruding large triangular surface either side of sacral base
promontory= anterior part of the body of the first sacral vertebra
How do you differentiate between a male and a female pelvis?
pelvic inlet
women = circular "gynaecoid" (due to less distinct promontory and broader ala) men = heart shaped "anthropoid"
pubic angle is wider in women
How is the pelvis orientated in the anatomical position?
pubic tubercle and ASIS are in the same vertical line
4 types of pelvis (shape)
gynaecoid
anthropoid
android
platypelloid