University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

46

Pages:

6
Author:

Mariam A. A.

Muscles of the pelvic wall Muscles Origin and Insertion Piriformis Origin: Anterior surface of sacrum between the sacral foramina Course and other important information • goes through a foramen called the greater sciatic foramen • flat pyramidal muscle • passes laterally to exist the body pelvis through the greater sciatic foramen attaching to the gluteal surface of the ilium close to the posterior iliac spine • divides the greater sciatic foramen into two foramina Insertion: greater trochanter - suprapiriform & infrapiriform - The superior gluteal artery and nerve (L4-S1) leave the pelvis through the suprapiriform foramen. - The sciatic nerve, inferior gluteal nerve (L5-S2) and artery, posterior femoral cutaneous nerve (S1-S3) and the nerve to quadratus femoris (L4-S1) leave the pelvis through the infrapiriform foramen The pudendal nerve (S2-4) also leaves the pelvis through the infrapiriform foramen, wraps around the sacrospinous ligament, and re-enters the pelvis by passing back into the lesser sciatic foramen. After re-entering the pelvis, it is joined by the internal pudendal artery and vein. Innervation and blood supply Action Innervation: Superior gluteal nerve Hip joint: Thigh external rotation, Thigh abduction (from flexed hip); Stabilizes head of femur in acetabulum Blood Supply: Superior gluteal artery, inferior gluteal artery, gemellar branches of the internal pudendal Obturator Origin: Posterior internus surface of the obturator membrane; bony boundaries of the obturator foramen Insertion: greater trochanter • bilateral triangular-shaped muscle situated deep within both the pelvic and gluteal regions • occupies true pelvis • medial surface of obturator muscle covered by obturator - central thickening provides attachment point of levator ani (pelvic diaphragm) - fascia is medially related to the obturator artery and nerve as they run anteroinferiorly from the anterior trunk on the lateral pelvic wall to the upper part of the obturator foramen Innervation: Nerve to obturator internus (L5 and S1) Blood Supply: Obturator artery; internal pudendal artery External rotation of extended thigh. Abduction of flexed thigh. Stabilization of hip joint