Psoas Major
Hip & Pelvis
A deep hip flexor connecting the lumbar spine directly to the femur — chronic shortening from prolonged sitting is a major contributor to lower back pain and anterior pelvic tilt.
Function
Flexes thigh and trunk; stabilizes lumbar spine
Origin
Bodies/discs T12-L5 and transverse processes L1-L5
Insertion
Lesser trochanter of femur
Innervation
Anterior rami L1-L3