The heel bone is the largest bone in the foot and absorbs the most amount of shock and pressure. A heel spur develops as an abnormal growth of the heel bone. Calcium deposits form when the plantar fascia pulls away from the heel area, causing a bony protrusion, or heel spur to develop. The plantar fascia is a broad band of fibrous tissue located along the bottom surface of the foot that runs from the heel to the forefoot. Heel spurs can cause extreme pain in the rearfoot, especially while standing or walking.

Cause Heel spurs develop as an abnormal growth in the heel bone due to calcium deposits that form when the plantar fascia pulls away from the heel. This stretching of the plantar fascia is usually the result of over-pronation (flat feet), but people with unusually high arches (pes cavus) can also develop heel spurs. Women have a significantly higher incidence of heel spurs due to the types of footwear often worn on a regular basis.