A calcaneal spur (or heel spur) is a small osteophyte (bone spur) located on the calcaneus (heel bone). Calcaneal spurs are typically detected by a radiological examination (X-ray).
When a foot bone is exposed to constant stress, calcium deposits build up on the bottom of the heel bone. Generally, this has no effect on a person's daily life. However, repeated damage can cause these deposits to pile up on each other, causing a spur-shaped deformity, called a calcaneal (or heel) spur. Obese people, flat footed people, and women who constantly wear high-heeled shoes are most susceptible to heel spurs.