Ligament · Knee

Arcuate popliteal ligament

Ligamentum popliteum arcuatum

A Y-shaped band at the back and outer corner of the knee. Its stem rises from the head of the fibula and its two arms arch over the tendon of popliteus where that muscle leaves the joint, one arm spreading into the back of the capsule and the other reaching the back edge of the intercondylar area of the tibia. It is one of the structures grouped as the posterolateral corner, and it is genuinely variable — well defined in some people and little more than a thickening of the capsule in others.