Pelvic Wall & Floor

Obturator internus origin

Ilium, ischium, obturator membrane

Obturator internus insertion

Greater trochanter of femur

Obturator internus action

Externally rotates hip joint, holds head of femur in acetabulum

Obturator internus innervation

Nerve to obturator internus (L5-S2)

Piriformis origin

S2-S4, greater sciatic notch, sacrotuberous ligament

Piriformis insertion

Greater trochanter of femur

Piriformis action

Externally rotates and abducts hip joint, holds head of femur in acetabulum

Piriformis innervation

Anterior rami S1, S2

Coccygeus origin

Ischial spine

Coccygeus insertion

Inferior end of sacrum/coccyx

Coccygeus action

Flex coccyx, forms part of pelvic floor

Coccygeus innervation

Branches of S4 and S5

Levator ani origin

Body of pubis, ischial spine

Levator ani insertion

Coccyx, anococcygeal ligament, prostate OR vagina, rectum, anal canal

Levator ani action

Forms most of pelvic floor, resists increases in intra-abdominal pressure

Levator ani innervation

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

Describe the orientation of the puborectalis/puborectal sling

Attaches to the internal surfaces of both pubic rami and wraps around the rectum, like a sling