Bony Pelvis And Pelvic Viscera

Question 1

Levator ani

Answer 1

Origin: body of pubis, tendinous arch of levator ani, ischial spine
Insertion: perineal body, coccyx, anococygeal ligament, walls of prostate or vagina, rectum, canal
Action: helps support pelvic viscera, resists increases in intraabdominal pressure
Innervation: nerve to levator ani (branches of S4), inferior anal nerve, coccygeal plexus

Question 2

Coccygeus

Answer 2

Origin: ishcial spine
Insertion: inferior end of sacrum and coccyx
Action: forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx
Innervation: branches of S4 and S5 nerves

Question 3

Obturator internus

Answer 3

Origin: pelvic surface of ilium and ischium, obturator membrane
Insertion: greater trochanter of femur
Action: laterally rotates hip joint, assists in holding head of femur in acetabulum
Innervation: nerve to obturator internus (L5, S1, S2)

Question 4

Piriformis

Answer 4

Origin: pelvic surface of 2nd-4th sacral segments, superior margin of greater sciatic notch and sacrotuberous ligament
Insertion: greater trochanter of femur
Action: laterally rotates hip joint, abducts hip joint, assists in holding head of femur in acetabulum
Innervation: anterior rami of S1 and S2

Question 5

Tendinous arch

Answer 5

Continuous bilateral band running from pubis to sacrum along pelvic floor adjacent to viscera