Hallux valgus, also known as bunion, is a deformity of the big toe joint that causes the big toe to turn inward toward the other toes. This can create a lump on the side of the foot, which can be painful and make it difficult to wear certain types of shoes. Hallux valgus is often caused by wearing tight or narrow shoes, genetics or certain medical conditions. Treatment may include wearing wider shoes, using orthotics or, in severe cases, surgery.