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
Limbs of the horse the body, which can then cause lameness or injuries. Poor conformation and structural defects do not always cause lameness, however, as was shown by the champion racehorse Seabiscuit, who was considered undersized and knobby-kneed for a Thoroughbred. Common defects of the forelegs include base-wide and base-narrow, where the legs are farther apart or closer together on the ground then they are when they originate in the chest; toeing-in and toeing-out, where the hooves point inwards or outwards; knee deviations to the front (buck knees), rear (calf knees), inside (knock knees) or outside (bowleg); short or long pasterns; and many problems