Posterior Abdominal Wall Muscles PDF

The Posterior Abdominal Wall Muscles of the posterior abdominal wall Psoas major Psoas minor Quadratus lumborum Iliacus Origin 1. Transverse process 1. From the 1. The posterior...

The Posterior Abdominal Wall Muscles of the posterior abdominal wall Psoas major Psoas minor Quadratus lumborum Iliacus Origin 1. Transverse process 1. From the 1. The posterior 5 cm of 1. From the of all lumbar sides of the inner lip of the upper 2/3 of vertebrae. the bodies iliac crest. iliac fossa. 2. Bodies of (T12-L5) & of (T12- 2. The iliolumbar intervertebral discs L1) and ligament. in between by five the disc in tendinous arches between. (which bridge over (present in the lumbar 60% of vessels). subjects) Insertion ❖ lesser trochanter of ❖ Iliopubic 1. The medial half of ❖ With the the femur eminence last rib. psoas major (Iliopsoas tendon). of the hip 2. The tips of transverse into the lesser bone. processes of (L1- L4). trochanter of the femur. Nerve ❖ L1, 2 & 3. ❖ L1. ❖ Subcostal nerve ❖ From the supply (T12). femoral nerve ❖ L1, 2, 3. (in the abdomen). Action 1. Flexion and lateral ❖ Weak A. On one side: lateral ❖ Assists the rotation of the thigh. flexor of flexion pf the trunk. psoas major If acting from below: the trunk B. On both sides: muscle in 2. On both sides: 1. Extend the lumbar flexion of the flexion of the trunk. part of vertebral thigh. 3. On one side: lateral column. flexion of the trunk. 2. Acts as a muscle of respiration. Clinical importance of psoas major:  TB infection of the vertebral column may spread through the blood to the vertebrae (hematogenous spread), particularly during childhood. An abscess resulting from tuberculosis in the lumbar region tends to spread from the vertebrae into the psoas sheath, where it produces a psoas abscess.  Pus from the psoas abscess passes inferiorly along the psoas muscle deep to the inguinal ligament to the superior part of the thigh.  Psoas Major & Iliacus muscles All 4 muscles of the posterior Psoas Minor muscle Abdominal wall  Lumbar plexus ❖ Location: Inside the psoas major ❖ Formation: Ventral rami of upper 4 lumbar nerves. ❖ Branches: Muscular: Named branches: 1. Psoas minor: L1. 1. Iliohypogastric: L1 2. Psoas major: L2, 3, 4. 2. Ilioinguinal: L1 3. Quadratus lumborum: L 1, 2, 3 3. Genitofemoral: L1, 2 4. Lateral cutaneous nerve of the thigh: L2, 3 5. Femoral nerve: L2, 3, 4 (posterior division) 6. Obturator nerve: L2, 3, 4 (anterior division) 7. Accessory obturator nerve: L2, L3 (anterior division) ❖ Relation of the psoas major to branches of the lumbar plexus: From its anterior surface: Genitofemoral nerve From its lateral border: Iliohypogastric nerve Ilioinguinal nerve Lateral cutaneous nerve of the thigh Femoral nerve From its medial border: Obturator nerve Lumbosacral trunk Relation of lumbar plexus nerves to psoas major muscle