Which muscle extends the leg at the knee?

Which muscle extends the leg at the knee?

• A. Hamstrings
• B. Latissimus dorsi
• C. Quadriceps
• D. Trapezius

Answer: (C)

Extending the knee, or straightening the leg, is done by the muscles on the front of the thigh known as the quadriceps. This group pulls on the patellar tendon, transmitting force to the tibia to straighten the knee. The hamstrings, on the back of the thigh, bend the knee rather than straighten it, so they oppose knee extension. The latissimus dorsi and trapezius are upper-body muscles involved with movements of the back, shoulders, and neck, not the knee. So the muscle that extends the leg at the knee is the quadriceps.

Extending the knee, or straightening the leg, is done by the muscles on the front of the thigh known as the quadriceps. This group pulls on the patellar tendon, transmitting force to the tibia to straighten the knee. The hamstrings, on the back of the thigh, bend the knee rather than straighten it, so they oppose knee extension. The latissimus dorsi and trapezius are upper-body muscles involved with movements of the back, shoulders, and neck, not the knee. So the muscle that extends the leg at the knee is the quadriceps.