Patent attributes
A pivotal bone anchor assembly includes a shank having a head portion and an anchor portion for fixation to the bone of a patient, and a receiver comprising a base defining a lower portion of central bore and a pair of upright arms defining a channel for receiving an elongate rod. The assembly also includes a retaining structure with a central opening configured to capture and pivotally retain and support the head portion of the shank in the retaining structure, and which is slidably movable relative to the receiver so as to provide for increased articulated movement between the shank and the receiver prior to locking the assembly with the elongate rod and a closure. The assembly further includes an insert configured to engage the elongate rod and the head portion of the shank when in use, and to have an overlapping configuration with the retaining structure when the assembly is in the locked configuration.
