A bunion is a structural anomaly of the bones and the joint between the foot and big toe, and it may be painful. A bunion is an enlargement of bone or tissue around the joint at the base of the big toe (metatarsophalangeal joint).
The big toe may turn in toward the second toe (angulation), and the tissues surrounding the joint may be swollen and tender.
Today the term usually is used to refer to the pathological bump on the side of the great toe joint.
The bump is the swollen bursal sac and/or an osseous (bony) anomaly on the mesophalangeal joint (where the first metatarsal bone and hallux meet).
Signs and symptoms
The McMaster kinesiology of symptoms of bunions include irritated skin around the bunion, pain when walking, joint redness and pain, and possible shift of the big toe toward the other toes. Blisters may form more easily around the site of the bunion as well.
Having bunions can also make it harder to find shoes that fit properly; bunions may force a person to have to buy a larger size shoe to accommodate the width the bunion creates.
Wearing high heels also becomes more of a problem for those with bunions as the heel puts pressure on the toes, which may be irritating to most people in general, but even more so in those with bunions.
Bunions are mostly genetic and consist of certain tendons, ligaments, and supportive structures of the first metatarsal that are positioned differently. This bio-mechanical anomaly may be caused by a variety of conditions intrinsic to the structure of the foot – such as flat feet, excessive flexibility of ligaments, abnormal bone structure, and certain neurological conditions.
These factors are often considered genetic. Although some experts are convinced that poor fitting footwear is the main cause of bunion formation, other sources concede only that footwear exacerbates the problem caused by the original genetic structure.
Bunions are commonly associated with a deviated position of the big toe toward the second toe, and the deviation in the angle between the first and second metatarsal bones of the foot.
The small sesamoid bones found beneath the first metatarsal (which help the flexor tendon bend the big toe downwards) may also become deviated over time as the first metatarsal bone drifts away from its normal position. Arthritis of the big toe joint, diminished and/or altered range of motion, and discomfort with pressure applied to the bump or with motion of the joint, may all accompany bunion development.