The arcuate popliteal ligament is an Y-shaped extracapsular ligament of the knee. It is formed as a thickening of the posterior fibres of the joint capsule of the knee. It has its origin at the posterior aspect of the head of the fibula. It has two insertions: the medial limb arches superficially over the tendon of the popliteus muscle to blend with the oblique popliteal ligament; the lateral limb passes to the lateral epicondyle of the femur (accompanied by the popliteus muscle tendon) to blend there with the lateral head of the gastrocnemius muscle.