Calcaneal spur: A bony spur projecting from the back or underside of the heel bone (the calcaneus) that often makes walking painful. A calcaneal spur is also called a heel spur.

Spurs at the back of the heel are associated with inflammation of the Achilles tendon (Achilles tendinitis) and cause tenderness and pain at the back of the heel that is made worse by pushing off the ball of the foot.

Spurs under the sole (plantar area) are associated with inflammation of the plantar fascia (the "bowstring-like" tissue stretching from the heel underneath the sole) and cause localized tenderness and pain made worse by stepping down on the heel.

Not all heel spurs cause symptoms. Some are discovered on X-rays taken for other purposes.

Heel spurs and plantar fasciitis can occur alone or be related to underlying diseases which cause arthritis (inflammation of the joints) such as Reiter's disease, ankylosing spondylitis, and diffuse idiopathic skeletal hyperostosis.

Treatment is designed to decrease the inflammation and avoid reinjury. Icing reduces pain and inflammation. Antiinflammatory agents (such as ibuprofen or injections of cortisone) can help. Heel lifts reduce stress on the Achilles tendon and relieve painful spurs at the back of the heel. Donut-shaped shoe inserts take pressure off plantar spurs. Infrequently surgery is done on chronically inflamed spurs.