The present application concerns a shoulder prosthesis assembly. The shoulder prosthesis assembly comprises a humeral stem including a first articulating coupling means, a base portion of a substantially disc shaped geometry including a second articulating coupling means. Said first articulating coupling means and said second articulating coupling means connect the stem to the base portion. The ratio between the circumference of the disc shaped base portion and the peripheral thickness of the disc shaped base portion is at least 18:1.
