An anchoring member is provided with a shaft 2, 12 for anchoring in a bone and a head 3, 53 with a substantially U-shaped cross-section for connection with a rod 9, 59, the head having a base 5, 55 connected with the shaft 2, 12 and two free legs 6, 7; 56, 57 forming a channel for receiving the rod 9,...http://www.google.co.uk/patents/US5961517?utm_source=gb-gplus-sharePatent US5961517 - Anchoring member and adjustment tool therefor
