The extensor apparatus of the hand is a complex system consisting of extrinsic and intrinsic muscles, which in combination enable the individual extension of the fingers. Extensor tendon injuries of the hand are frequent injuries and the operative or conservative treatment options are determined by the localization and involvement of osseus structures. For an optimal outcome of the treatment of extensor tendon injuries, correct diagnostics and a consistent hand aftercare are absolutely essential. The crucial decision making regarding the further procedure starts with the initial patient treatment, ideally on the day of trauma.