Posterior Abdominal Wall Muscles

Quadratus Lumborum

psoas major

psoas minor

Iliacus

Quadratus Lumborum

psoas major

psoas minor

iliacus

Iliopsoas

Psoas major proximal attachment

Bodies of T12 - L5 and adjoining discs

TPs of L1-L5, along their anterior and lower borders

Psoas major distal attachment

lesser trochanter of femur (with iliacus)

Psoas major action (open chain)

flexes the hip

psoas major action (closed chain)

powerful vertebral flexor

posts major innervation

Branches from ventral rami of L1 - L3

Psoas minor proximal attachment

Vertebral bodies of T12 and L1 and adjoining discs

Psoas minor distal attachment

superior ramus of pubis at the iliopectineal line

Psoas minor action

weak trunk flexor

psoas minor innervation

Branch from L1 spinal nerve

quadratus lumborum proximal attachment

12th rib, along the inferior border

Transverse processes of L1-L4, along the tip

quadratus lumborum distal attachment

iliac crest, posteromedially

quadratus lumborum action (open chain)

lateral flexion of the trunk

what does the quadratus lumborum stabilize during inspiration?

12th rib

quadratus lumborum innervation

branches from ventral rami T12-L3

illiacus proximal attachment

Superior 2/3 of iliac fossa

Ala of sacrum

Inner lip of iliac crest

Anterior SI ligament and iliolumbar ligament

iliacus distal attachment

lesser trochanter of femur (with psoas major)

iliacus action

flexes the hip

iliacus innervation

Femoral nerve (L2, L3)