| 摘要 |
The instrument consists of a threaded shank (1) which is preferably about 2 mm in diameter, with a head (2) connected by a zone of reduced resistance (3) to the tip (4) of a detachable fixing tool. The distal end of the screw shank has an angle of taper of about 60 degrees, and has its threads cut by three lengthwise grooves (50) with sides (51, 52) lying at right angles to one another so that one, lying in a radial plane, forms a bone cutting edge. The head of the screw also has three notches (23) which are used to finish tightening or for removing it. |
