Pelvis Flashcards
Inferior hypogastric plexus
Recieves pre-ganglionic parasympathetic fibres from
S2 - S4
Inferior hypogastric plexus form on posterior abdominal wall as extensions of abdominal pre-vertebral plexus
Post-ganglionic fibres penetrate pelvic floor –>
Innervate erectile tissue in males and females
Sacrum
Five sacral vertebrae fused
Has 4 anterior sacral foramina
Has 4 posterior sacral foramina
Sacral canal posteriorly which is a continuation of vertebral canal
Zygapophysial joints
Joints between adjacent inferior and superior articular processes of L5 and S1
Ligaments of the sacro-iliac joints
Anterior sacro-iliac ligaments
-thickening of the fibrous memrbane of the joint capsule
Interosseous sacro-iliac ligament
- largest, strongest
- posteriosuperior to joint and attach on roughended areas on ilium and sacrum
Posterior sacro-iliac ligament
-covers the interossesous sacro-iliac ligament
Ligaments between L5 –> ilium/sacrum
Lumbosacral ligament
-Transverse process L5 –> sacrum
Ileolumbar ligament
-Iliac crest –> transverse process of L5
Ligaments of pubic symphysis joint
Superior pubic ligament
-located above the joint
Inferior pubic ligament
-located below joint
Female vs male pelvis
Female pelvis
- circular inlet
- pubic arch 80-85
- ischial spines don’t project
Male pelvis
- heart-shaped inley
- pubic arch 50-60
- pojecting ischial spines + prominent sacral promonotory
Sacrospinous ligament
Smaller of the two ligaments
Triangular, apex attached to ischial spine
Base attached to margins of sacrum and coccyx
More anterior vs sacrotuberous ligament
Sacrotuberous ligament
Larger of the two, sits posterior to sacrospinous
Triangular
Base has broad attachment that extends from posterior superior iliac spine –> coccyx
Attaches to medial margin of ischial tuberosity
Innervation of obturator internus
Innervated by nerve to obturator internus
L5 S1
O: deep surface of obturator membrane and surrounding bone
I: Medial surface of greater trochanter of femur
-tendon leaves pelvic cavity through lesser sciatic foramen, makes a 90 bend around ischium –> posterior to hip –> greater trochanter
F: Lateral rotation of extended hip
Abduction of flexed hip
Innervation of piriformis
Innervated by branches from (L5) S1 + S2
O: Anterior surface of sacrum between the four anterior sacral foramina
I: Medial side of superior border of greater trochanter of femur
F: Lateral rotation of extended hip
Abduction of flexed hip
Obturator canal
Supeior defect in obturator membrane
Borders:
- Superior pubic ramus
- Obturator internus, externus, and membrane
Contants
- Obturator nerve
- Obturator vessels
Greater sciatic foramen
Borders:
- greater sciatic notch
- sacrspinous ligament (posterior)
- sacrotuberous ligament (inferior)
- spine of ischium
Piriformis divides into two compartments
Superior to piriformis
- Superior gluteal nerve
- Superior gluteal vessels
Inferior to piriformis
- Inferior gluteal nerve
- Inferior gluteal vessels
- Internal pudendal vessels
- posterior femoral cutaenous nerve
- nevre to obturator internus
- nerve to quadrate femoris
Innervation of levator ani
Innervated by:
- inferior rectal branch of internal pudendal nerve
- direct branches from ventral ramus of S4
O: line around pelvic wall
- ischial spine
- tendinous arch
- obturator internus
- pubic bone
I:
- anterior: superior surface of perineal mambrane
- posterior: meets partner on perineal body, around anal canal and along anococcygeal ligament
F: reinforces pelvic floor, reinforces sphincters
Innervation of coccyges
Innervated by direct branches from ventral rami of S3 and S4
O: ischial spine and pelvic surface of sacrospinous ligament
I: lateral margin of coccyx and related border of sacrum
F: contributes to formation of pelvic floor which support viscera and pulls coccyx forward after defecation
