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
Posterior cutaneous nerve of thigh Posterior cutaneous nerve of thigh The posterior cutaneous nerve of the thigh (also called the posterior femoral cutaneous nerve) provides innervation to the skin of the posterior surface of the thigh and leg, as well as to the skin of the perineum. The posterior cutaneous nerve of the thigh is a nerve from the sacral plexus. It arises partly from the dorsal divisions of the first and second, and from the ventral divisions of the second and third sacral nerves, and issues from the pelvis through the greater sciatic foramen below the piriformis muscle. It then descends beneath the gluteus