Bunion

A bunion (hallux valgus) is a deformity characterized by lateral deviation of the great toe, often erroneously described as an enlargement of bone or tissue around the joint at the head of the big toe (metatarsophalangeal joint).

Bunions are specifically caused by the long-term use of shoes, particularly tight-fitting shoes with pointed toes. Bunions occur when pressure is applied to the side of the big toe (hallux) forcing it inwards towards, and sometimes under or over, the other toes (angulation). As pressure is applied, the tissues surrounding the joint may become swollen and tender. Because bunions are, in all cases, caused by footwear, they are completely unknown in cultures that do not wear shoes.

The bump itself is partly due to the swollen bursal sac or an osseous (bony) anomaly on the mesophalangeal joint (where the first metatarsal bone and hallux meet). The larger part of the bump is a normal part of the head of the first metatarsal bone that has tilted sideways to stick out at its top.

Read more about Bunion:  Definition, Signs and Symptoms, Pathophysiology, Treatment