An apparatus includes a support member and a retention member. The support member has at least a portion configured to be disposed between a first spinous process and a second spinous process. The retention member is movably coupled to an end portion of the support member. The retention member is configured to displace a bodily tissue. The retention member is configured to move relative to the support member from a first position to a second position. The retention member is configured to limit movement of the support member along the longitudinal axis and relative to the first spinous process and the second spinous process when in the second position.
