Coffin bone The coffin bone is completely encased in the hoof. The shape of the hoof is determined by the shape of the coffin bone. A front foot will have a rounded, flattened, and wide coffin bone, whereas a back foot will have a pointed, comparatively steep, and narrow coffin bone. The rounded toe allows the horse to break over in the center of the toe. The narrow hind hoof allows the horse to turn easily from side to side. The function of the coffin bone is to provide for the attachment of the deep digital flexor tendon and protection of blood vessels and nerves.