<p>A medical instrument includes a housing (2), a stylet (55) having a portion in the housing, a cannula (21) coaxially receiving the stylet and having a portion in the housing, and a member (7) slidably coupled to the housing. The stylet and the cannula are movable between an extended position and a retracted position. The member is configured with primary (8) and secondary (13) bars to move the stylet and the cannula from their extended positions to their retracted positions.</p>
