A calcaneal spur is a bony outgrowth from the calcaneal tuberosity (heel bone). Calcaneal spurs are typically detected by x-ray examination. It is a form of exostosis. When a foot is exposed to constant stress, calcium deposits build up on the bottom of the heel bone.A calcaneal spur, or commonly known as a heel spur, occurs when a bony outgrowth forms on the heel bone. Calcaneal spurs can be located at the back of the heel (dorsal heel spur) or under the sole (plantar heel spur). The dorsal spurs are often associated with achilles Tendinopathy, while spurs under the sole are associated with Plantar fasciitis.
The apex of the spur lies either within the origin of the planter fascia (on the medial tubercle of the calcaneus) or superior to it (in the origin of the flexor digitorum brevis muscle). The relationship between spur formation, the medial tubercle of the calcaneus and intrinsic heel musculature results in a constant pulling effect on the plantar fascia resulting in an inflammatory response. Symptomatic calcaneal spurs are often found in association with plantar fasciitis. Like plantar fasciitis, calcaneal spurs can occur alone or may be part of a systemic inflammatory condition such as rheumatoid arthritis, Reiter's syndrome, or gout. In some patients, the cause seems to be entirely mechanical, and such patients often exhibit an abnormal gait with excessive heel strike. High-impact aerobic exercise has also been implicated in the development of calcaneal spur syndrome.