Paragraph Number

62

FIG. 2D illustrates details of a head feature 107 of the screw 104. The raised ridges 216 on the head 210 of each of the screws 104 may have sloping faces 218 that slope toward the distal end 204 of the screw 104, along the clockwise direction. The sloping faces 218 may be connected by engagement faces 220 that are parallel to or more nearly parallel to the axis of the screw 104. Thus, the raised ridges 216 may be readily driven clockwise into the bone with a driver (not shown) with mating engagement ridges that engage the engagement faces 220. Such a mating interface may not generally be suitable for rotating the screw 104 counterclockwise, as the engagement ridges may slide along the sloping faces rather than transmitting counterclockwise torque. Thus, the raised ridges 216 may present an interface that facilitates driving the screws 104 into the bones 102 and keeping them in place, but not withdrawal of the screws 104 from the bones.

Added by DJM 5 2021