what is a calcaneal exostosis
Retrocalcaneal Exostosis / Achilles Heel Spur. Pain on the back of the heel if often caused by an overgrowth of bone on the back of the heel bone (calcaneus). This is called a retrocalcaneal exostosis. Retrocalcaneal exostosis problems are often related to chronic tugging of a tight Achilles tendon on the back of the heel.