A medical instrument having a proximal control handle and a distal tool that are intercoupled by an elongated instrument shaft that is meant to pass internally of an anatomic body, proximal and distal movable members that respectively intercouple the proximal control handle and the distal tool with the instrument shaft, cable control means disposed between the movable members, an actuation member at the handle for controlling the distal tool through the movable members, and a coupler for selectively engaging or disengaging the shaft portion of the instrument from the handle portion. The handle has a distal receiver portion, and a shaft connector on said proximal motion member is selectively engageable with and releaseable from the receiver portion.