Abstract: In one embodiment, a spinal fixation assembly includes an elongated member, such as a spinal rod, configured for placement adjacent the spine and a bone engaging fastener, such as a bone screw having a lower portion configured for engaging a vertebra and a head that is at least partially spherical. The assembly further includes a receiver member defining a bore therethrough from a top end to a bottom end, a recess for receiving the head of the bone screwing fastener therein, and a lower opening at said bottom end of the receiver member through which the bone screw extends. The recess is configured to at permit pivoting of the bone screw within the receiver member until the head is fixed within the recess. The receiver member also includes a channel communicating with the bore and having an upper opening at the top end of the receiver member for insertion of the spinal rod into the channel.

Abstract: A multi-function stalk switch that incorporates a pushbutton switch, a first rotary switch and a second rotary switch onto the end of a stalk, wherein further switching functions may be executed by moving the entire stalk in either of two orthogonal planes. The stalk switch incorporates many design features that enable it to be assembled at low cost from a small number of parts. One such feature is the use of plastic-on-plastic detents to control positioning of the rotary switches so that they wipe across predetermined portions of a flexible printed circuit board. Another feature is the inclusion of a spring-loaded plunger detent riding in a concave centering mechanism that is operable to automatically return the stalk switch to its central (neutral) position after removal of external biasing forces. A further feature is the inclusion of magnets on the stalk switch and Hall effect sensors fixedly mounted nearby in order to sense movement of the magnets (and therefore the stalk) in two orthogonal planes.