Pelvic floor muscles

Question 1

Puborectalis

Answer 1

Origin: Posterior surface of bodies of pubic bones

Insertion: None (forms ‘puborectal sling’ posterior to rectum)

Innervation: Nerve to levator ani (S4)

Blood supply:
Inferior gluteal, inferior vesical and pudendal arteries

Function:
Stability and support of the abdominal and pelvic organs, resistance against increased intra-abdominal pressure, opening and closing of the levator hiatus

Question 2

Pubococcygeus

Answer 2

Origin:
Posterior surface of bodies of pubic bones (lateral to puborectalis)

Insertion:
Anococcygeal ligament, Coccyx, Perineal body and musculature of prostate/vagina

Innervation:
Nerve to levator ani (S4); branches via inferior rectal/perineal branches of the pudendal nerve (S2-S4)

Blood supply:
Inferior gluteal, inferior vesical and pudendal arteries

Function:
Stability and support of the abdominal and pelvic organs, resistance against increased intra-abdominal pressure, opening and closing of the levator hiatus

Question 3

Iliococcygeus

Answer 3

Origin:
Tendinous arch of the internal obturator fascia, Ischial spine

Insertion:
Anococcygeal ligament, Coccyx

Innervation:
Nerve to levator ani (S4)

Blood supply:
Inferior gluteal, inferior vesical and pudendal arteries

Function:
Stability and support of the abdominal and pelvic organs, resistance against increased intra-abdominal pressure, opening and closing of the levator hiatus

Question 4

Coccygeus

Answer 4

Origin:
Ischial spine

Insertion:
Inferior end of sacrum, Coccyx

Innervation:
Anterior rami of spinal nerves S4-S5

Blood supply:
Three branches of the internal iliac artery; inferior vesical, inferior gluteal and internal pudendal arteries

Function:
Assisting levator ani to support the pelvic viscera