Hammertoes are a contracture of the toes as a result of a muscle imbalance between the tendons on the top and the tendons on the bottom of the toe. They can be flexible or rigid in nature. When they are rigid, it is not possible to straighten the toe out by manipulating it. Frequently, they develop corns on the top of the toe as a result of rubbing on the shoe. They may also cause a bothersome callous on the ball of the foot. This occurs as a result of the toe pressing downward on the bone behind the toe. This area then becomes prominent and the pressure of the bone against the ground causes a callous to form. (Corns and Calluses)

They tend to slowly get worse with time and frequently flexible deformities become rigid. Treatment can be preventative, symptomatic or curative. (For information on hammertoe of the big toe see Hallux hammertoe)

Source: Kirk A. Koepsel, D.P.M.