Abstract: A medullary canal plug for use for example, when inserting the stem of a bone joint replacement into a bone canal. The plug comprising a substantially hemispherical center and a plurality of individual leaves radiating from the flat face of the center with the adjacent edges of the leaves angularly inclined relative to the faces to facilitate the partial overlapping of the leaves, when moved from a planar disposition to a frusto conical position during insertion into the bone canal.