A myoelectric electrode assembly (10) for a prosthesis comprising a retention ring (12) adapted to be inserted into a correspondingly shaped aperture in the wall of the prosthesis. The assembly (10) also has a myoelectric electrode unit (30) held within the retention ring (12) by means of a gasket (40) which surrounds the electrode unit (30) and is in sealing engagement therewith. A portion (46, 48) of the gasket (40) is received in and sealingly engages with an annular recess (26) around the inside of the retention ring (12).
