Ligament · Knee

Oblique popliteal ligament

Ligamentum popliteum obliquum

A broad expansion crossing the back of the knee from the inner side upward and outward, and unlike most ligaments it is not an independent structure: it is a slip of the semimembranosus tendon that turns away from the bone and spreads across the capsule to reach the femur above the outer condyle. That gives it an unusual property — a muscle can tighten it. It forms the floor of the popliteal fossa, the diamond-shaped hollow behind the knee, and the popliteal artery lies directly upon it.