S04.2Non-Billable (Header)Injury of trochlear nerveChild CodesS04.20Injury of trochlear nerve, unspecified sideS04.21Injury of trochlear nerve, right sideS04.22Injury of trochlear nerve, left sideCode Hierarchy└S04Injury of cranial nerve└S04.2Injury of trochlear nerve└S04.2Injury of trochlear nerve