A polyaxial orthopedic device for use with rod implant apparatus includes a screw having a curvate head and a coupling element. The coupling element has a tapered lower portion including a slotted interior chamber in which the curvate head is initially polyaxially disposed; a recess formed in its side...http://www.google.com/patents/US5549608?utm_source=gb-gplus-sharePatent US5549608 - Advanced polyaxial locking screw and coupling element device for use with rod fixation apparatus
