A surgical assembly (20) comprises a post (100) having a longitudinally extending axis (104), a support (56) for resisting movement of the post in a negative longitudinal direction, and a platform (70) offset from the support in a positive longitudinal direction. The platform includes an opening (82) through which the post projects. The opening includes a throat (86). The post has a first dimension which renders the post incapable of passing through the throat and a second dimension which renders the post capable of passing through the throat. Alternate embodiments in which the post can be removably engaged with the support and platform and disengaged therefrom without translating the post in the longitudinal direction are also disclosed.
