The Haglund’s deformity is a bone enlargement on the back of the heel, but is notably different from a spur. The top surface of the back of the heel bone is normally a rounded but generally flat surface that has nothing attached to it, unlike the back of the heel where the Achilles tendon attaches. In some people, this surface is rounded upward. Although this can be present from an early age, some people gradually develop the bump as the bone surface becomes irritated. This irritation can be due to high arches, in which the heel bone is angled steeply upward, delivering the top of the heel closer to the Achilles tendon which produces the irritation. Shoes with a hard heel liner can also cause the irritation, hence the name ‘pump bump‘. The bone surface eventually becomes enlarged enough to irritate the soft tissue covering the back of the heel above where the Achilles tendon attaches. Within this tissue are fibers associated with the Achilles tendon, as well as a pad of tissue called a bursal sac, which serves as a sort of pillow to separate the bone from the overlying soft tissue. The bursal sac can become inflamed and cause pain. The more it is irritated against the enlarged bone, the more pain is felt with activity or with shoes that rub against the bone.