Which is a hip lateral rotator?

• A. Rectus femoris
• B. Tensor fasciae latae
• C. Piriformis
• D. Gluteus maximus

Answer: (C)

Turning the thigh outward at the hip is the job of external rotator muscles around the hip joint. Among the options, the piriformis is the one that functions as a lateral (external) rotator of the hip. It sits deep in the buttock, attaching from the sacrum to the greater trochanter, and its line of pull causes the femur to rotate outward when the hip is extended. It can also assist with hip abduction when the hip is flexed, but its hallmark action here is external rotation.

Rectus femoris is part of the quadriceps and primarily flexes the hip and extends the knee, so rotation isn’t its main role. Tensor fasciae latae mainly abducts and medially rotates the thigh (and helps stabilize the knee via the iliotibial tract), not outward rotation. Gluteus maximus is the major hip extensor and can contribute to external rotation, especially when the hip is extended, but piriformis is the classic external rotator emphasized in this context.