Patent attributes
A pivotal bone anchor assembly includes a shank with a head, an anchor portion, and a neck extending between the head and the anchor portion, and a receiver with upright arms defining a channel for receiving a rod and a central bore extending downward to a lower portion of the receiver. The assembly also includes a retaining structure rotatably coupled with the receiver with an internal seating structure pivotally supporting the head while providing for independent rotation of the shank prior to locking the assembly with the rod and a closure. The retaining structure includes an external surface and a slot extending between the seating structure and the external surface with a concave cut-out configured to closely receive the neck so as to provide for increased articulation between the shank and the receiver along the slot, and with the shank and the retaining structure being rotatable together around a centerline axis to align the increased articulation in any radial direction around the circumference of the receiver.
