Patent ID: 8870926

Claim:
A fastener assembly configured to affix a longitudinal member to a vertebra, the fastener assembly comprising: a fastener that defines a central axis and includes a lower portion configured to engage the vertebra, and an upper portion that extends up with respect to the lower portion, such that the upper portion is disposed in an upward direction with respect to the lower portion, the upper portion having a channel surface that defines a channel that is configured to receive the longitudinal member, the channel surface including two points that are opposite each other along a direction parallel to the central axis; and an attachment member positionable on the upper portion, the attachment member including an inner surface that defines a slot, such that the slot cooperates with the channel so as to capture the longitudinal member when the attachment member is positioned on the upper portion, wherein (i) the inner surface defines an outer section having a first center of curvature and an inner concave section having a second center of curvature that is offset inwards toward the central axis with respect to the first center of curvature and (ii) the outer section of the inner surface includes a plurality of serrations configured to mate with a plurality of ridges on the longitudinal member, wherein the inner surface at the outer section is offset with respect to the inner surface at the inner section in the upward direction.