runner's toe? 一般都是穿的鞋子不合适造成的.

http://en.wikipedia.org/wiki/Runner%27s_toe

Runner's toe is a common condition seen in runners caused by downward pressure or horizontal separation of nail plate from the nail bed. This repetitive traumatic injury leads to bleeding and pooling of blood underneath the nail plate. Clinically, it is characterized by red black discoloration of the toe nail