Also called: iliopsoas (with iliacus)
The psoas major is a long muscle on the back wall of the abdomen. It arises from the lumbar vertebrae and their discs and inserts with iliacus on the lesser trochanter of the femur. Branches from the lumbar plexus supply it, and it is the main flexor of the hip.
| Origin | Sides of the bodies and intervertebral discs of T12 to L4 and the transverse processes of L1 to L5. |
|---|---|
| Insertion | Lesser trochanter of the femur (by the common iliopsoas tendon). |
| Innervation | Anterior rami of L1-L3. |
| Blood supply | Lumbar branches, iliolumbar artery and the external iliac artery. |
| Action | Flexes the thigh at the hip; with the thigh fixed it flexes the lumbar spine. |
3D model: BodyParts3D (CC BY 4.0), adult male reference anatomy. Highlighted structure shown with nearby bones for context.
With the iliacus it forms the iliopsoas, the strongest hip flexor. The lumbar plexus lies within the muscle and the genitofemoral nerve emerges on its anterior surface.
The combined psoas major and iliacus, which share a tendon inserting on the lesser trochanter and flex the hip.
On the lesser trochanter of the femur.
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