Muscles

Question 1

psoas major

Answer 1

transverse processes of lumbar vertebrae, sides of bodies of T12-S1 vertebrae and intervening IV discs

lesser trochanter of femur

lumbar plexus via ant branches of nerves L2-4

acting inferiorly with iliacus flexing thigh, acting superiorly flexes vertebral column laterally to balance trunk, when sitting, acts inferiorly with iliacus to flex trunk

Question 2

iliacus

Answer 2

sup 2/3 of iliac fossa, ala of sacrum, and ant sacro-iliac ligaments

lesser trochanter of femur and psoas major tendon

femoral nerve (L2-4)

flexes thigh and stabilises hip joint
acts with psoas major (iliopsoas)

Question 3

quadratus lumborum

Answer 3

medial half of inf border of 12th rib and tips of lumbar transverse processes

iliolumbar ligament and internal lip of iliac crest

ant branches of T12 and L1-L4 nerves

extends and laterally flexes vertebral column
fixes 12th rib during inspiration