The present invention provides a clamp assembly which allows the surgeon to snap a bone fixation assembly onto a bone fixation rod at an intermediate location along the length of the rod. It is not necessary to “thread” the clamp onto the rod starting at the end and sliding it down the length of the rod to the desired location. In particular, this invention provides a novel clamp assembly for use with standard bone fixation rods, and bone pins. The clamp allows the interconnection of a bone fixation rod with a bone pin locking assembly including a bone pin vise. The clamp is a single-piece construction, having a jaw capable of loosely capturing the bone fixation rod when the surgeon presses the jaw onto the rod. The assembly may be rigidly fixed to the rod using a bolt which tightens the jaw onto the rod.