This International Standard specifies dimensions and tolerances for metal bone screws used in surgery, having hexagonal drive connection, spherical under-surface of the head, and shallow and deep asymmetrical threads. NOTES 1 The mechanical requirements for screws that are cited in this International Standard are specified in ISO 6475. 2 The interrelationship of International Standards dealing with bone screws, bone plates and relevant tools is shown for information in annex B.