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
Articular capsule of the knee joint Articular capsule of the knee joint The articular capsule of the knee joint (commonly referred to as capsular ligament) is wide and lax; thin in front and at the side; and contains the patella ("knee cap"), ligaments, menisci, and bursae. The capsule consists of a synovial and a fibrous membrane separated by fatty deposits anteriorly and posteriorly. Anteriorly, the reflection of the synovial membrane lies on the femur; located at some distance from the cartilage because of the presence of the suprapatellar bursa. Above, the reflection appears lifted from the bone by underlying periosteal connective tissue. In a standing posture,