A screw insertion system has a screw (12) having a threaded shaft (25) and a head (22). The head (22) has a conically tapered outer surface, the taper increasing in distance from a central longitudinal axis (28) of the screw (12) from a free end of the head towards a larger diameter adjacent the connection between the head (22) and the threaded shaft (25). The conically tapered head (22) outer surface has preferably two helically extending partially rounded threads (40). The head (22) has a drive element (20) for engaging a driver (16). A tubular screw holder (14) has an outer surface and internal bore extending between a leading end and a trailing end for receiving the screw (12). The leading end having a conically tapered inner threaded portion (26) for engaging the conically tapered outer thread of the screw head (22). The tubular screw holder (14) outer surface having a diameter less than or equal to the maximum diameter of the conically tapered head (22).