Heel spurs are bony growths from the underside of the front part of the heel bone, the calcaneus . They are believed to be formed by stretching and tearing of the fibrous band supporting the arch of the foot, the plantar fascia , and tearing away of the lining of the heel bone where the fibrous band connects.
New bone can grow in the areas where the bone s lining has been torn away.
These growths of new bone are called heel spurs and are visible by x-ray. In most cases, it is not the spur that causes heel pain. Heel pain can be present with or without evidence of a heel spur on x-ray of the foot. The same stretching and tearing that can lead to the formation of a spur causes microtears and degeneration of the plantar fascia, the long fibrous band that connects the heel to the ball of the foot and supports the longitudinal arch. The resulting inflammation, called plantar fasciitis, makes the area painful after periods of rest which allow the fascia to heel in a relaxed, rather than in a flexed position.