Which muscle is located on the lateral aspect of the thigh and extends the knee?

Which muscle is located on the lateral aspect of the thigh and extends the knee?

• A. Vastus Lateralis
• B. Gracilis
• C. Sartorius
• D. Tensor Fasciae Latae

Answer: (A)

The main idea is to match a muscle’s location with its action. On the outer, or lateral, side of the thigh, a major muscle that straightens the knee is part of the quadriceps group. The vastus lateralis runs along the lateral thigh and, like the other quadriceps muscles, its fibers converge into the quadriceps tendon and then the patellar ligament to the tibia. Its primary action is knee extension, helping to straighten the leg. The other muscles listed don’t fit as well: gracilis is on the medial thigh and mostly adducts the thigh and flexes the knee; sartorius runs diagonally across the thigh and helps with hip flexion and knee flexion/rotation; tensor fasciae latae is a hip muscle that tightens the fascia lata and stabilizes the iliotibial tract, not a knee extensor.

The main idea is to match a muscle’s location with its action. On the outer, or lateral, side of the thigh, a major muscle that straightens the knee is part of the quadriceps group. The vastus lateralis runs along the lateral thigh and, like the other quadriceps muscles, its fibers converge into the quadriceps tendon and then the patellar ligament to the tibia. Its primary action is knee extension, helping to straighten the leg.

The other muscles listed don’t fit as well: gracilis is on the medial thigh and mostly adducts the thigh and flexes the knee; sartorius runs diagonally across the thigh and helps with hip flexion and knee flexion/rotation; tensor fasciae latae is a hip muscle that tightens the fascia lata and stabilizes the iliotibial tract, not a knee extensor.