a condition marked by a tender swelling on the os calcis due to a thickening of the periosteum or fibrous tissue covering the back of the os calcis.
prom·i·nent heel
(prom'i-nĕnt hēl) A condition marked by a tender swelling on the calcaneus, due to a thickening of the periosteum or fibrous tissue covering the back of the calcaneus.