Hammertoe is a deformity in which there is downward bending of the middle joint (proximal interphalangeal joint or PIP joint) of the toe. Although it can affect any toe, hammertoe most commonly forms in the second toe. It may be present at birth or result from wearing shoes that are too tight, which forces the toe to bend forward. Over time, you may lose flexibility of the toe and not be able to straighten it. With constant rubbing from ill-footing footwear, the top region of the toe may form a corn and the sole may form a callus. Wearing shoes and walking usually becomes painful. Hammer toe can be treated by straightening and splinting the toe, performing stretching exercises or undergoing surgery for severe cases.