The present invention provides a surgical instrument for guiding a drill into bone, the surgical instrument comprising; an elongate body comprising a shaft having a handle towards its proximal end and a head towards its distal end, wherein the head comprises a mouth and jaw assembly, and the shaft comprises a lumen aligned with the longitudinal axis of the shaft and extending from the proximal end of the surgical instrument to the mouth of the shaft, wherein the lumen is suitable for receipt and passage of a drill, and the jaw assembly comprises a pair of opposed reciprocating arms.