An abnormally increased ability to bend (dorsiflex) one's fifth finger. To assess this feature, the examiner requests to proband to extend the elbows,to bend the wrist back so that it forms a ninety degree angle to the forearm, and to extend the fingers. Then, the proband is requested to bend the fifth finger back as far as is possible without discomfort. If the angle of the fifth finger exceeds 90 degrees, this is considered to be abnormal. [from HPO]