An alignable coupling assembly embodiment for coupling distal and proximal prosthetic components includes a pair of parallel circular plates rotatably disposed in the circular receptacle of a support plate. The circular plates are configured such that they can be unpressed or a pressed. The unpressed condition allows rotation of the paired plates and the pressed condition prevents such rotation by way of a first friction lock. The paired circular plates further have a rectangular slot into which a longitudinal connector is slidably disposed, and which is subject to a second friction lock that prevents sliding when the connector is pulled distally. Rotational movement of the plates and sliding movement of the connector in the slot cooperate to allow its positioning at any point within an anterior-posterior/lateral medial grid centered on the longitudinal axis of the proximal prosthetic component. A distal pull on the longitudinal connector engages both first and second friction locks.