Quadriceps femoris

Quadriceps femoris is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the great extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur.

Anatomy

The quadriceps femoris is a composite muscle, combining the forces of the vastus lateralis, vastus medialis, vastus intermedius, and the rectus femoris. Each of these muscles has its own area of origin but they all share a common insertion point at the patella via the quadriceps tendon.

Vastus Lateralis

The vastus lateralis originates from the greater trochanter, intertrochanteric line, and linea aspera of the femur. It extends the length of the thigh and inserts into the lateral base and border of the patella.

Vastus Medialis

The vastus medialis originates from the lower half of the intertrochanteric line and medial lip of the linea aspera. It extends the length of the thigh and inserts into the medial base and border of the patella.

Vastus Intermedius

The vastus intermedius originates from the upper two-thirds of the anterior and lateral surfaces of the femur. It lies between the vastus lateralis and vastus medialis on the front of the femur, and its fibers end in a superficial aponeurosis, which forms the deep part of the quadriceps tendon.

Rectus Femoris

The rectus femoris originates from the anterior inferior iliac spine and the exterior surface of the bony ridge which forms the groove on the iliac portion of the acetabulum. It extends the length of the thigh and inserts into the base of the patella.

Function

The quadriceps femoris is the most powerful muscle in the body and is responsible for extending the knee and flexing the hip. It is crucial for walking, running, jumping and squatting.

Clinical Significance

Injury or disease of the quadriceps femoris can lead to difficulty in performing basic motor tasks. Quadriceps tendonitis, quadriceps strain, and quadriceps tendon rupture are common conditions that affect this muscle group.