This is a side (lateral) view of the foot. This patient had a painful heel. The arrow identifies the spur on the inferior aspect of the heel bone (calcaneus).

This is a side (lateral) view of the heel bone, and demonstrates a spur on the back (posterior) surface of the heel bone (calcaneus). This was asymptomatic (without pain or other symptoms). A tight Achilles tendon can cause this to form. It may be associated with pain at the back of the heel, were the Achilles tendon inserts into the calcaneus.