The heel is the prominence at the posterior en of the foot. It is based on the projection of one bone, the calcaneus, behind the articulation of the bones of the lower leg. In the long-footed mammals, both the hoofed species (unguligrade) and the clawed forms which walk on the toes (digitigrade), the heel is well above the ground at the apex of the angular joint known as the hock. In plantigrade species it rests on the ground.