The bifurcated ligament (internal calcaneocuboid, interosseous ligament or bifurcate ligament) is a strong band, attached behind to the deep hollow on the upper surface of the calcaneus and dividing in front in a Y-shaped manner into a calcaneocuboid and a calcaneonavicular part. It is commonly injured in "sprain-type" inversion injuries producing an avulsion fracture at the anterolateral process of the calcaneus.