A double-jointed bone bolt for use in an apparatus for maintaining vertebra in a desired relationship. The apparatus has a rod that extends substantially along the spine and one or more bone bolts. At least one of the bone bolts is double jointed. The double-jointed bolt has a mounting portion with a...http://www.google.com/patents/US20030105460?utm_source=gb-gplus-sharePatent US20030105460 - Multidirectional pivoting bone screw and fixation system
