A bunion is generally considered as an enlargement of the joint (a lump of bone) at the base and side of the big toe - (specifically, the first metatarsophalangeal joint). Bunions form when the toe moves out of place. As the big toe bends towards the others this lump becomes larger and the bunion can become painful - arthritis and stiffness can eventually develop. Hallux valgus or hallux abducto valgus (HAV) is the name used for the deviated position of the big toe and a bunion refers to the enlargement of the joint - most of the time the two go together and can just be referred to as 'bunions'.
The word bunion is from the Latin "bunion," meaning enlargement.
Wearing footwear that is too tight or causing the toes to be squeezed together are the most commonly blamed factor for the cause of bunions and hallux valgus and is undoubtedly the main contributing factor. This probably is the reason for the higher prevalence of bunions among women. However, studies of some indigenous populations that never wear footwear, show that they also get bunions - BUT, they are very uncommon. As they do get bunions, factors other than footwear must play a role in the cause, even though footwear is the main culprit for providing the pressure that causes the symptoms.
Bunions are most widely considered to be due to an imbalance in the forces that is exerted across the joint during walking. The resulting abnormal motion and pressure over the joint, over many years (combined with poor fitting footwear) leads to instability in the joint causing hallux valgus and bunions. Bunions are really only a symptom of faulty foot mechanics and are usually caused by a combination of the way we walk, the foot we inherit and inappropriate footwear use. Bunions are not inherited but do tend to run in families. What is inherited is the poor or faulty foot type, that mechanically can lead to the instability around the joint that will eventually lead to bunions - how soon, how quickly and how bad they are or become is assumed to be very dependant on the footwear.
A number of other factors are known to play a role in the cause of bunions and hallux valgus. Bunions can follow foot injuries and develop in those with neuromuscular problems. Those with flat feet or pronated feet appear to be more prone to the instability of the joint and have a higher incidence of bunions. Some activities (eg ballet dancing) puts added pressure on the joint and may increase the chance of bunions developing.
There are many treatment options for bunions and they will vary with the type and severity of each bunion and will also depend on what is causing the symptoms. Bunions are almost always progressive and tend to get larger and more painful with time - how fast this happens may be a function of the fit of the footwear.
The initial goal of treatment options is to relieve pressure on the bunion and any symptoms that may be present and to halt or slow the progression of the joint deformity. There is no effective may be "get rid off" a bunion without surgery.