Patent attributes
A pivotal bone anchor assembly includes a receiver having an upper portion defining a channel for receiving a rod and a base defining a central bore with a seating surface adjacent a lower opening and a cut-out portion extending radially outward from the lower opening that is defined, in part, by one or more downward-facing planar surfaces. The assembly includes a shank having a capture portion with rounded shape including a spherical lower outer surface extending downward toward a neck, and an anchor portion opposite the capture portion. The capture portion is positionable into the central bore with the lower outer surface in pivotal engagement with the seating surface and the shank extending downward through the lower opening, and with the neck of the shank being positionable in the cut-out portion of the lower opening to provide for increased pivotal angulation of the shank with respect to the receiver.