Which muscle tightens the iliotibial band to stabilize the knee?

• A. Biceps femoris
• B. Sartorius
• C. Rectus femoris
• D. Tensor fasciae latae

Answer: (D)

Tension on the iliotibial band to stabilize the knee is produced by the Tensor fasciae latae. This muscle originates on the pelvis and attaches into the iliotibial tract, so when it contracts it pulls on the IT band, tightening it along the outside of the thigh. That taut band helps keep the knee aligned during weight-bearing, especially as the leg moves through flexion and extension, providing lateral stability.

The other muscles listed don’t directly tighten the IT band. Biceps femoris acts mainly on knee flexion and hip extension; sartorius crosses the leg but isn’t involved in tensioning the IT band; rectus femoris is a hip flexor/knee extender and doesn’t pull on the IT band either.