Hallux valgus occurs with lateral deviation of the great toe and medial deviation of the first metatarsal. Commonly, the deformity is characterized by progressive subluxation of the first metatarsophalangeal joint. Occasionally, there is a static deformity due to valgus angulation of the distal articular surface of the first metatarsal or the proximal phalangeal articular surface.

Hallux valgus occurs almost exclusively in shoe-wearing societies. Coughlin and Thompson, noting the extremely high prevalence of bunions in American women in the fourth, fifth, or sixth decade of life, implicated constricting footwear as a cause of hallux valgus. This notion is supported by a study from China, where the prevalence of hallux valgus was fifteen times higher in people who wore shoes than in those who did not. Likewise, in Japan, Kato and Watanabe noted that the prevalence of hallux valgus in women increased dramatically following the introduction of high-fashion footwear after World War II.