This invention relates to a medical appliance, in particular an apparatus for the extracorporeal blood treatment, with a housing including a door and with a handle mechanism arranged at the door, by means of which the door can be locked with the housing via a locking mechanism, wherein a part of the locking mechanism is formed at the handle mechanism in its part protruding into the housing and wherein a form-fit unit is provided which includes at least one form-fit means and at least one form-fit means counterpart, wherein on locking and/or closing the door the at least one form-fit means at least partly engages in the at least one form-fit means counterpart.
