The bone nail is provided with a tapered portion having a barbed denticulation and a conical head which has a conical shaped depression at the proximal end for receiving a centering cone of the setting and driving instrument. The instrument carries a movable sleeve at the distal end for engaging and...http://www.google.co.uk/patents/US4776328?utm_source=gb-gplus-sharePatent US4776328 - Bone nail and an instrument for implanting a bone nail
