X-Ray demonstrating a calcaneal spur
A calcaneal spur (or heel spur) is a radiological (X-ray) finding, and when it is located on the inferior aspect of the calcaneus, is often associated with plantar fasciitis and ankylosing spondylitis. A posterior calcaneal spur may also develop on the back of the heel at the insertion of the Achilles tendon.
An inferior calcaneal spur consists of a spike of calcification, which lies superior to the plantar fascia at the insertion of the intrinsic foot musculature onto the calcaneus. Until recently, an inferior calcaneal bone spur was erroneuously thought to develop at the insertion of the plantar fascia. While heel spurs are commonly associated with plantar fascitis, they are not caused by plantar fasciitis and many people who suffer from plantar fasciitis do not have heel spurs. Often times, inferior heels spurs do not have to be removed as part of the treatment for plantar fascitis. However, posterior heel spurs are often large and palpable through the skin and may need to be removed as part of the treatment of insertional Achilles tendonitis.