posterior abdominal wall

Question 1

psoas major - deep layer

Answer 1

O: L1-L5 (costal processes)
I: Femur (lesser trochanter);
joint insertion as iliopsoas muscle
N: direct branches from lumbar plexus (L2-L4)
A: ~hip joint- flexion & external rotation
~lumbar spine (with femur fixed):
Unilateral: contraction bends trunk laterally
Bilateral: contraction raises trunk from supine position

Question 2

psoas minor

Answer 2

O: T12, L1 vertebrae and IV disk (lateral surfaces)
I: pectin pubis;
iliopubic ramus;
iliac fascia;
lowermost fibers may reach inguinal ligament
N: direct branches from lumbar plexus (L2-L4)
A: weak flexor of the trunk

Question 3

iliacus

Answer 3

O: iliac fossa
I: lesser trochanter of femur ???
N: femoral nerve (L2-L4)
A: ??

Question 4

quadratus lumborum

Answer 4

O: iliac crest
iliolumbar ligament 
I: 12th rib;
L1-L4 vertebrae (transverse processes)
N: T12, L1-L4 spinal nerves 
A: unilateral- bends trunk to same side
bilateral- bearing down and expiration;
stabilizes 12th rib

Question 5

psoas major - superficial layer

Answer 5

O: T12-L4 vertebral bodies and associated IV disks (lateral surfaces)
I: Femur (lesser trochanter);
joint insertion as iliopsoas muscle
N: direct branches from lumbar plexus (L2-L4)
A: ~hip joint- flexion & external rotation
~lumbar spine (with femur fixed):
Unilateral: contraction bends trunk laterally
Bilateral: contraction raises trunk from supine position