Bunion (a word usually derived from the Ital. bugnone, a swelling, but, according to the New English Dictionary, the late and rare literary use of the word makes an Italian derivation unlikely; there is an O. Eng. word "bunny," also meaning a swelling, and an O. Fr. buigne, modern bigne, showing a probable common origin now lost, cf. also "bunch"), an inflamed swelling of the bursa mucosa, the sac containing synovial fluid on the metatarsal joint of the big toe, or, more rarely, of the little toe. This may be accompanied by corns or suppuration, leading to an ulcer or even gangrene. The cause is usually pressure; removal of this, and general palliative treatment by dressings, etc. are usually effective, but in severe and obstinate cases a surgical operation may be necessary.