A heel spur is a pointed growth of extra bone on the heel bone (calcaneus). It may form when the plantar fascia, the connective tissue extending from the bottom of the heel bone to the base of the toes (ball of the foot), pulls excessively on the heel. The spur may be painful as it develops but it may become less painful as the foot adjusts to it. Not all heel spurs cause symptoms. When heel spurs do cause symptoms, most can be treated without surgery.