A calcaneal spur is a heel spur, a bony formation found on the back of the heel. It is diagnosed on an x-ray. There is often pain from the condition and it interferes with the ability to walk. Cause The location of the calcaneal spur tells you where the irritation to the bone is occurring. A spur is the body’s way of protecting itself from irritation. The spur may be found at the bottom of the back of the heel, or higher up on the heel. A calcaneal spur may also be the result of a foot condition called plantar fascitis, Achilles tendonitis, or ankylosing spondylitis. Treatment and Prevention In severe cases, a calcaneal spur may be surgically removed. Otherwise, methods to relieve the pain and irritation are recommended, which include orthotic inserts and/ or cushioned arch supports. The reason why these are helpful is that they cushion the heel and provide the support of the foot so that the bones of the foot line up. If a calcaneal spur is caused by plantar fascitis, then specific plantar fascitis heel supports, lifts or cups as well as inserts or arch supports will help.