| 摘要 |
<p>A bone plate (15) is provided with a keyhole shaped aperture (10) having a first wide portion (20) leading into a second narrow portion (22) by way of a discontinuous narrowing (24). The narrow portion (22) has a concave recess (26) in the upper surface (11) of the plate and a bevel (28) in the bone contacting surface (13) at its end remote from the wide portion. In use, a screw (30) can be inserted obliquely across a fracture (40) and does not need to be countersunk in the bone, nor removed and replaced to allow fitting of the plate (15). The wide portion (20) of the hole (10) passes over the head (32) of the screw (30), the plate is then slide (arrow a) so that the head (34) lies in the narrow portion (22). Once the screw is fully tightened its head sits in the concave recess (26) and because of the narrowing (24), it prevents the plate sliding back. The screw shank (34) adjacent the head is accommodated in the bevel (28). Further bone screws can then be secured via other apertures (12, 14, 16, 18) in the plate (15).</p> |
