Hammer toe is a deformity of the toes that causes the middle toe to bend and resemble a hammer. This condition is common among people who wear poorly fitting shoes or those who have muscle imbalance. This condition can cause pain and discomfort, and the development of calluses and corns due to constant rubbing against the top of the shoes. If left untreated, hammer toe can cause permanent damage and may require surgery to correct the deformity. Luckily, hammer toe can be prevented and treated by wearing shoes that give your feet adequate room, along with targeted exercises to stretch and strengthen the muscles.