| 摘要 |
<p>The craniotomy provides a dura shield (31, 32) mounted on a ring (26) which can turn freely about the axis of the rotary cutter (14. A plastic disc (28) is put between the ring and the body of the instrument, to reduce friction. The freely -turning ring (26) is held against the face of the instrument by a flanged sleeve (25, 24) through which the cutter (14) passes. The end (33) of the cutter turns a bore in the foot (32) of the dura shield.</p> |
