Muscles of Pelvic Wall and Floor

Question 0

Coccygeus (ishiococcygeus)

Answer 0

Origin: Ischial spine

Insertion: Inferior end of sacrum

Insertion: branches of S4 and S5

Question 1

Levator Ani (pubo/ilio)

Answer 1

Origin: Body of pubis, tendinous arch of levator ani, ischial spine

Insertion: Perineal body, coccyx, anococcygeal ligament, walls of prostate or vagina, rectum, anal canal

Innervation: Nerve to levator ani (branches of S4), inferior anal (rectal nerve) coccygeal plexus

Question 2

Obturator Internus

Answer 2

Origin: Pelvic surface of ilium and ischium, obturator membrane

Insertion: Greater trochanter of femur

Innervation: Nerve to Obturator internus (L5-S2)

Question 3

Piriformis

Answer 3

Origin: Pelvic surface of 2nd-4th sacral segments; superior margin of greater sciatic notch and sacrotuberous ligament

Insertion: Greater trochanter of femur

Innervation: Anterior rami of S1,2