A modular humeral prosthesis suitable for implant in a humeral seating of a humerus comprises an articulation component, a distal joint element able to be inserted into said humeral seating along an insertion axis, and an adapter body provided with a support positionable in the humeral seating and that has a coupling seating to connect said articulation component and provided with a connection unit inserted into said support to connect said distal joint element to said adapter body in a releasable manner. The connection unit comprises a clamping element associated in a selectively releasable manner to the distal joint element and the support has a through coupling seating configured to receive and position said clamping element inside it, and also configured to allow the insertion and extraction of said distal joint element through said support without removing said support from the humeral seating.