What action does the psoas major perform at the hip?

What action does the psoas major perform at the hip?

• A. Flexion
• B. Abduction
• C. Flexion and lateral rotation of thigh at hip
• D. Extension

Answer: (C)

The psoas major is the primary hip flexor, crossing the hip joint from the lumbar spine to the femur. When it contracts, it pulls the femur upward, producing flexion at the hip. Its fibers run obliquely and attach near the lesser trochanter, so as the thigh is flexed, the psoas major also contributes to external (lateral) rotation of the thigh. It does not primarily abduct or extend the hip; those actions are handled by other muscles. So the best description is flexion of the hip with lateral (external) rotation of the thigh when the hip is flexed.

The psoas major is the primary hip flexor, crossing the hip joint from the lumbar spine to the femur. When it contracts, it pulls the femur upward, producing flexion at the hip. Its fibers run obliquely and attach near the lesser trochanter, so as the thigh is flexed, the psoas major also contributes to external (lateral) rotation of the thigh. It does not primarily abduct or extend the hip; those actions are handled by other muscles. So the best description is flexion of the hip with lateral (external) rotation of the thigh when the hip is flexed.