A medical access device for creating an access to a body for minimally invasive intervention has a hollow body assembled from at least two parts having longitudinal extending edges. Each part has a distal body portion and at an angle to the latter a proximal body portion. A locking mechanism locks the assembled proximal hollow body portions. The locking mechanism has a hook projecting from an edge of a proximal body. A nose of the hook can enter from proximal to distal in a recess in an edge joining said edge having said hook.