Human leg the femur. All four muscles unite in a common tendon inserted into the patella from where the patellar ligament extends it down to the tibial tuberosity. Fibers from the medial and lateral vasti form two retinacula that stretch past the patella on either sides down to the condyles of the tibia. The quadriceps is "the" knee extensor, but the rectus femoris additionally flexes the hip joint, and articular muscle of the knee protects the articular capsule of the knee joint from being nipped during extension. The sartorius runs superficially and obliquely down on the anterior side of the thigh, from
Biceps femoris muscle head is a weaker hip extender when the knee is flexed. When the knee is semi-flexed, the biceps femoris in consequence of its oblique direction rotates the leg slightly outward. Avulsion of the biceps femoris tendon is common in sports that require explosive bending of the knee as seen in sprinting. Biceps femoris muscle The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group. It has two heads of origin: The two muscle