A bunion is a bony bump that has formed on the joint of your big toe, at the base. This bump bulges out on the outside of your big toe, often causing redness, pain, or swelling in the area. Bunions can also develop on the joint of the little toe, in which case they are called bunionettes. Restricted movement or soreness in the area of the big toe joint can be common, and corns or calluses often develop where the first and second toes overlap, due to the big toe pushing against the next toe. Bunions usually occur when your big toe pushes against the toe next to it, which forces the big toe joint to grow bigger and stick out. Bunions can also occur due to a medical condition such as arthritis, an inherited defect of that joint, or stress on the foot. Bunions usually don't require medical attention, unless the condition is causing pain, decreased movement of the big toe, or interfering with daily activities.