1. PAW.pdf

 Posterior abdominal wall Quadratus Lumborum  Origin: iliac crest & ilio-lumbar Ligament  Insertion: Transverse process of upper 4 lumbar vertebrae & Last rib.  Nerve supply: subcostal & upper 3 or 4 lumbar nerves  Action: Unilateral acti...

 Posterior abdominal wall Quadratus Lumborum  Origin: iliac crest & ilio-lumbar Ligament  Insertion: Transverse process of upper 4 lumbar vertebrae & Last rib.  Nerve supply: subcostal & upper 3 or 4 lumbar nerves  Action: Unilateral action: lateral flexion of trunk Bilateral action: Extension of trunk Iliacus  Origin: iliac fossa & ala of sacrum  Insertion: Lesser trochanter of femur.  Nerve supply: femoral nerve  Action: Flexion of thigh Anatomist “Posterior abdominal wall” Posas major  Origin: Body of T12 & all lumbar vertebrae & inter-vertebral disc between  Insertion: Lesser trochanter of femur.  Nerve supply: upper 3 lumbar nerves  Action:  With iliacus: Flexion of thigh  Unilateral action: lateral flexion of trunk.  Bilateral action: Flexion of trunk Posas minor “may be absent”  Origin: Body of T12 & L1  Insertion: Ilio-pubic eminence.  Nerve supply: L1  Action: weak flexion N.B: TB infection of vertebral column may cause formation of abscess in psoas sheath called psoas abscess. The pus of psoas abscess may spread down to the thigh through psoas sheath Anatomist “Posterior abdominal wall”  Lumbar plexus Site: Inside psoas major Formation: Ventral rami of upper 4 lumbar nerves Arrangement & branches:  L1: gives iliohypogastric , ilioinguinal  L1,2 forms genito-femoral nerve  L2,3 form LCN of thigh  L2,3,4 divide into anterior & posterior division to form:  Obturator nerve "from anterior division"  Femoral nerve "from posterior division  L3,4 form obturator accessory Relation to posas major: Lateral to psoas major:  Iliohypogastric  Ilioinguinal  LCN of thigh  Femoral nerve Anterior to psoas major: Genitofemoral nerve Medial to psoas major:  Obturator nerve  Obturator accessory nerve Anatomist “Posterior abdominal wall”