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ANATOMY
Medicine Made Simple
, POSTERIOR ABDOMINAL WALL
Made up of 3 bony & 4 muscular structures
Bones- Bodies of lumbar vertebrae
Sacrum
Wings of ilium
(11th & 12th ribs)
Muscles - Diaphragm
Quadratus lumborum
Psoas major & minor
Iliacus
Psoas major
Origin - transverse process of all lumbar vertebrae
Side of the bodies (T12-L5 )
Intervening discs (T12-L5 )
Insertion - lesser trochanter of femur
Action – flexion of the hip joint
Roots of lumbar plexus lie within the substance of the muscle.
Genitofemoral nerve - front of psoas
Femoral, Iliohypogastric, ilioinguinal, lateral femoral cutaneous
nerves, femoral nerve - lateral border
Obturator & lumbosacral trunk - medial border
Nerve supply - first 3 lumbar nerves
Psoas fascia - invests the surface of psoas major
- Attached to vertebral bodies, fibrous arches & transverse processes
- Thickening, curving from body of L1
(or L2) to transverse process of L2 - medial arcuate ligament
Clinical
Psoas abscess
enclosed in sheath
pus from tubercular infection may tract down through the sheath in to the thigh
soft swelling in the femoral triangle
Iliacus
Origin - Upper 2/3 of iliac fossa, anterior sacroiliac and iliolumbar ligament.
Insertion - lesser trochanter of femur along with the psoas tendon
Nerve supply - femoral nerve (L2-L4)
Iliac fascia - covers iliacus muscle
Attached to the margins of the muscle & to the inguinal ligament
Quadratus lumborum
Origin - transverse process of vertebra LV, the iliolumbar ligament, and the adjoining
part of the iliac crest
Insertion - attach superiorly to the transverse processes of the first four lumbar
vertebrae and the medial half of the inferior border of rib XII.
Nerve supply - anterior rami of T12 and L1 to L4 spinal nerves.
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ANATOMY
Medicine Made Simple
, POSTERIOR ABDOMINAL WALL
Made up of 3 bony & 4 muscular structures
Bones- Bodies of lumbar vertebrae
Sacrum
Wings of ilium
(11th & 12th ribs)
Muscles - Diaphragm
Quadratus lumborum
Psoas major & minor
Iliacus
Psoas major
Origin - transverse process of all lumbar vertebrae
Side of the bodies (T12-L5 )
Intervening discs (T12-L5 )
Insertion - lesser trochanter of femur
Action – flexion of the hip joint
Roots of lumbar plexus lie within the substance of the muscle.
Genitofemoral nerve - front of psoas
Femoral, Iliohypogastric, ilioinguinal, lateral femoral cutaneous
nerves, femoral nerve - lateral border
Obturator & lumbosacral trunk - medial border
Nerve supply - first 3 lumbar nerves
Psoas fascia - invests the surface of psoas major
- Attached to vertebral bodies, fibrous arches & transverse processes
- Thickening, curving from body of L1
(or L2) to transverse process of L2 - medial arcuate ligament
Clinical
Psoas abscess
enclosed in sheath
pus from tubercular infection may tract down through the sheath in to the thigh
soft swelling in the femoral triangle
Iliacus
Origin - Upper 2/3 of iliac fossa, anterior sacroiliac and iliolumbar ligament.
Insertion - lesser trochanter of femur along with the psoas tendon
Nerve supply - femoral nerve (L2-L4)
Iliac fascia - covers iliacus muscle
Attached to the margins of the muscle & to the inguinal ligament
Quadratus lumborum
Origin - transverse process of vertebra LV, the iliolumbar ligament, and the adjoining
part of the iliac crest
Insertion - attach superiorly to the transverse processes of the first four lumbar
vertebrae and the medial half of the inferior border of rib XII.
Nerve supply - anterior rami of T12 and L1 to L4 spinal nerves.
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