Which muscle extends the knee and lies on the lateral side of the thigh?

Which muscle extends the knee and lies on the lateral side of the thigh?

• A. Vastus Lateralis
• B. Rectus Femoris
• C. Vastus Medialis
• D. Vastus Intermedius

Answer: (A)

Knee extension is produced by the quadriceps femoris group, and the muscle that lies on the outer (lateral) side of the thigh is the vastus lateralis. It originates from the femur (lateral lip of the linea aspera and nearby areas) and inserts into the quadriceps tendon, which attaches to the patella so its contraction straightens the knee. While the rectus femoris also extends the knee, it sits more centrally on the front of the thigh and crosses the hip, and the vastus medialis is on the inner side while the vastus intermedius lies deep between the other vasti. So the lateral thigh muscle that extends the knee is vastus lateralis.

Knee extension is produced by the quadriceps femoris group, and the muscle that lies on the outer (lateral) side of the thigh is the vastus lateralis. It originates from the femur (lateral lip of the linea aspera and nearby areas) and inserts into the quadriceps tendon, which attaches to the patella so its contraction straightens the knee. While the rectus femoris also extends the knee, it sits more centrally on the front of the thigh and crosses the hip, and the vastus medialis is on the inner side while the vastus intermedius lies deep between the other vasti. So the lateral thigh muscle that extends the knee is vastus lateralis.