Congenital radioulnar synostosis

Radioulnar synostosis is a rare condition where there is an abnormal connection between the radius and ulna bones of the forearm. This can be present at birth (congenital), when it is a result of a failure of the bones to form separately, or following an injury (post-traumatic).It typically causes restricted movement of the forearm, in particular rotation (pronation and supination), though is not usually painful unless it causes subluxation of the radial head. [Source: Wikipedia ]