Posterior heel pain, or pain felt along the back side of the heel, can be brought on by several causes. A bone spur may have developed, often as a consequence of friction between the Achilles tendon and the calcaneus, or heel bone. Tendinitis or other damage to the Achilles tendon, which crosses the back of the ankle and attaches to the heel, can bring on significant posterior heel pain, particularly if the tendon has ruptured. Additionally, bursitis can afflict this region, as the small sacs or bursa between the Achilles tendon and the calcaneus are susceptible to inflammation. As these conditions are so closely related, they tend to develop not in isolation but concurrently, and they are common in athletes and active people.
The heel is the portion of the foot that sits beneath the ankle joint at the back end of the foot. It consists of the posterior end of the calcaneus bone and is covered by several tendons, nerves, and blood vessels running beneath the skin from the back of the leg to the sole of the foot, although these vessels tend to curve around from either side of the ankle so as not to be stepped upon directly. The most significant tissue covering the posterior heel is the Achilles tendon, which arises from the muscles of the calf and attaches them to the calcaneus. When these muscles contract, the Achilles pulls upward on the posterior heel, pointing the foot downward during many common motions like jumping, running, and climbing stairs.
Over time and with a great deal of activity, wear and tear on this tendon can occur, a common cause of posterior heel pain. The Achilles can become chronically inflamed, a condition known as tendinitis. Tendinitis leads to an inflammatory response around the tendon, one of which is swelling and therefore increased friction on the heel bone. It only worsens if the activity that led to the condition is not decreased or stopped, and if untreated increases the risk of an Achilles tendon rupture, in which the tendon tears away from the muscle belly or the bone.
Conditions leading to tendinitis can also do damage to the heel bone where the Achilles attaches, causing a retrocalcaneal bone spur to develop. This is a small outgrowth of bone that comes on where the tendon meets the calcaneus. Afflicting active individuals as well as the obese, it occurs as a protective response by the body to damage to the bone, such as extra weight and excessive pulling on the bone. A retrocalcaneal bone spur is felt as acute posterior heel pain, particularly when wearing shoes that rub against the spur.
Retrocalcaneal bursitis may also cause posterior heel pain. This condition occurs when the bursa, a sac of lubricating fluid that cushions the tendon against direct friction with the bone, becomes inflamed. It then swells, creating more friction in the very space where it functions to decrease friction. Like tendinitis, retrocalcaneal bursitis tends to be caused by excessive movement at the afflicted site and can be a source of significant posterior heel pain.