Methods and apparatuses for trialing a humeral head

A system for aligning components of a prosthetic includes a mounting plate, a fastener and an adapter coupling plate. The mounting plate comprises: a first major surface; a second major surface opposing the first major surface; an adapter accommodation hole extending through the mounting plate; and sizing indicia located on the second major surface. The fastener extends from the mounting plate. The adapter coupling plate comprises: a third major surface; a fourth major surface opposing the third major surface; an adapter coupling hole extending through the adapter coupling plate and surrounded by the adapter accommodation hole; and an indicator located on the fourth major surface to point to the sizing indicia on the mounting plate. The adapter coupling plate can be slidable along a slot surrounding the fastener or a tongue and groove system connecting the adapter coupling plate and the mounting plate and locked via the fastener.