Anatomy of the psoas (and related muscles)
- Origin: Transverse processes of T12-L5 and the lateral aspects of the discs between T12 and L5.
- Insertion: Lessor trochanter of the femur.
- Action: hip flexion (considered a primary hip flexor), lateral flexion of the lumbar spine, stabilization of the lumbar spine, stabilization of the hip, external rotation of the femur, adductor of the leg when starting in an abducted position, and controller of lumbar lordosis.
- Origin: lateral surface bodies of T12-L1 vertebrae and intervening intervetebral disc.
- Insertion: Pectineal line and iliopubic eminence.
- Action: weak trunk flexor, aids in stabilization of spine and hip joint, lateral flexor of the trunk.
- Origin: Psoas, as mentioned above originates on the transverse processes of T12-L5 and the lateral aspects of the intervening discs and the Iliacus originates on the upper two-thirds of the iliac fossa.
- Insertion: lessor trochanter of the femur.
- Action: hip flexion (primary hip flexor), flexor of the lumbar spine on the pelvis, forward/anterior tilting of the pelvis, lateral rotation of the femur, stabilization of the lumbar spine, stablization of the hip, lateral flexion of the lumbar spine.