Anatomy - MOINA of the Pelvic Wall and Floor Muscles (Snell and Braddom)

origin of piriformis

Snell: front of lateral mass of the sacrum

Braddom: anterior sacrum

insertion of piriformis

Snell: greater trochanter of femur

Braddom: posterior surface of greater trochanter

innervation of piriformis

Snell: sacral plexus

Braddom: S1-S2 via nerve to piriformis

action of piriformis

Snell: lateral rotator of femur at hip joint

Braddom:

• lateral rotation, abduction of thigh

• retroversion of pelvis

origin of obturator internus

Snell: obturator membrane and adjoining part of the hip bone

Braddom: pelvic surface of ilium, ischium, and obturator membrane

insertion of obturator internus

Snell: greater trochanter of femur

Braddom: posterior surface of greater trochanter

innervation of obturator internus

Snell: nerve to obturator internus from sacral plexus

Braddom: L5, S1-S2 via nerve to obturator internus

action of obturator internus

Snell: lateral rotator of femur at hip joint

Braddom: lateral rotator of thigh

origin of coccygeus

Snell: spine of the ischium

Braddom: ischial spine

insertion of coccygeus

Snell:

• lower end of sacrum

• coccyx

Braddom: lower sacral and upper coccygeal bones

innervation of coccygeus

Snell: 4th and 5th sacral nerve

Braddom: S3-S5, direct innervation from sacral nerve roots

action of coccygeus

Snell:

• assists levator ani to support the pelvic visceral

• flexes coccyx

Braddom: supports fetal head

origin of levator ani (Snell)

body of pubis, fascia of obturator internus, and spine of ischium

insertion of levator ani (Snell)

• perineal body

• anococcygeal body

• walls of prostate, vagina, rectum, and anal canal

innervation of levator ani (Snell)

• 4th sacral nerve

• pudendal nerve

action of levator ani (Snell)

• supports pelvic visceral

• sphincter to anorectal junction and vagina

origin of puborectalis (Braddom)

pubic symphysis

insertion of puborectalis (Braddom)

pubic symphysis

innervation of puborectalis (Braddom)

S3-S5, direct innervation from sacral nerve roots

action of puborectalis (Braddom)

raises pelvic floor

origin of pubococcygeus (Braddom)

posterior pubic bone and arcus tendineus

insertion of pubococcygeus (Braddom)

anococcygeus ligament and coccyx

innervation of pubococcygeus (Braddom)

S3-S5, direct innervation from sacral nerve roots

action of pubococcygeus (Braddom)

maintains floor tone in upright position

origin of iliococcygeus (Braddom)

ischial spine and arcus tendineus

insertion of iliococcygeus (Braddom)

anococcygeal raphe and coccyx

insertion of iliococcygeus (Braddom)

anococcygeal raphe and coccyx

action of iliococcygeus (Braddom)

voluntary control of urination