Psoas Major

Musculus psoas major

Core CoreHip FlexorsAnterior ChainLegs

The psoas major is the deepest and most powerful hip flexor, spanning from the lumbar spine to the femur and joining iliacus as the iliopsoas. It drives the leg-raising and knee-drive of sprinting, climbing, and loaded carries, and it links spinal posture to hip mechanics. Chronically shortened psoas (from prolonged sitting) can drive anterior pelvic tilt, so lifters often pair hip-flexor strength with mobility.

Actions

Hip flexion, Hip external rotation (weak), Lumbar spine flexion / lateral flexion, Anterior pelvic tilt

Origin

Transverse processes of L1-L5, lateral bodies of T12-L5 vertebrae and the intervening intervertebral discs

Insertion

Lesser trochanter of the femur (via the iliopsoas tendon, shared with iliacus)

Innervation

Anterior rami of the lumbar plexus (L1-L3)

Blood supply

Lumbar branches of the iliolumbar artery

Wikipedia ↗

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