A surgical retention port particularly useful as an arthroscopic port for shoulder surgery is provided. The surgical retention port has a long pointed instrument such as a trocar or obturator, an inner cannula extending around the pointed instrument, a plurality of rotatable fingers coupled to the inner cannula, and an outer cannula extending around the inner cannula. In one embodiment of the invention, the inner cannula and long pointed instrument are keyed such that rotation of the long pointed instrument can effect rotational movement of the inner cannula. Rotation of the inner cannula in turn causes the rotation of the fingers from a first position where the fingers assume a collapsed configuration to a second position where the fingers assume an extended or open configuration.