A shieldable needle assembly comprising: a needle cannula having a proximal end and a distal tip; a guard having a proximal end, an opposed distal end and a side wall extending therebetween, said guard being slidably movable along said needle cannula from a first position substantially adjacent said proximal end of said needle cannula to a second position where said distal tip of said needle cannula is intermediate said opposed proximal and distal ends (45, 46) of said guard; a hinged arm having proximal and distal segments (53, 55) articulated to one another through a hinge, for movement between a first position where said segments are substantially collapsed onto one another and a second position where said segments are extended from one another, said proximal segment of said hinged arm being articulated to a portion of said needle assembly adjacent said proximal end of said needle cannula, said distal segment of said hinged arm being articulated to said guard, said proximal and distal segments (53, 55) of said hinged arm having respective lengths for permitting said guard to move from said first position to said second position on said needle cannula, and for preventing said guard from moving distally beyond said second position; a spring connected to said hinged arm and said guard; and a first contact surface on a first radial projection extending from an end of said distal segment of said hinged arm near said hinge, wherein said first contact surface facing away from said guard when the guard is in said second position and a second contact surface on a second radial projection extending from an end of said proximal segment of said hinged arm near said hinge, said second contact surface facing said guard when said guard is in said second position, characterised in that said first and second contact surfaces (73, 75) being positioned to contact each other after said guard is in said second position, for limiting continued opening rotation of said proximal and distal segments around said hinge after said guard is in said second position, wherein said guard includes a clip, said clip having a distal wall biased against said distal tip of needle cannula when said guard is in said second position on said needle cannula. a needle cannula having a proximal end and a distal tip; a guard having a proximal end, an opposed distal end and a side wall extending therebetween, said guard being slidably movable along said needle cannula from a first position substantially adjacent said proximal end of said needle cannula to a second position where said distal tip of said needle cannula is intermediate said opposed proximal and distal ends (45, 46) of said guard; a hinged arm having proximal and distal segments (53, 55) articulated to one another through a hinge, for movement between a first position where said segments are substantially collapsed onto one another and a second position where said segments are extended from one another, said proximal segment of said hinged arm being articulated to a portion of said needle assembly adjacent said proximal end of said needle cannula, said distal segment of said hinged arm being articulated to said guard, said proximal and distal segments (53, 55) of said hinged arm having respective lengths for permitting said guard to move from said first position to said second position on said needle cannula, and for preventing said guard from moving distally beyond said second position; a spring connected to said hinged arm and said guard; and a first contact surface on a first radial projection extending from an end of said distal segment of said hinged arm near said hinge, wherein said first contact surface facing away from said guard when the guard is in said second position and a second contact surface on a second radial projection extending from an end of said proximal segment of said hinged arm near said hinge, said second contact surface facing said guard when said guard is in said second position, characterised in that said first and second contact surfaces (73, 75) being positioned to contact each other after said guard is in said second position, for limiting continued opening rotation of said proximal and distal segments around said hinge after said guard is in said second position, wherein said guard includes a clip, said clip having a distal wall biased against said distal tip of needle cannula when said guard is in said second position on said needle cannula.