Safety syringe and needle shield

A safety syringe comprising:

• a barrel having a distal end and a proximal end;
• a plunger sealingly slidable within the barrel;
• a collar having proximal and distal ends;
• a hollow needle attached to the distal end of the barrel;
• and
• an elongate generally tubular needle shield which is moveable over the barrel from a first proximally retracted configuration in which a distal portion of the hollow needle is exposed to a second distally extended configuration in which the hollow needle is fully within the elongate generally tubular needle shield, said elongate generally tubular needle shield having a proximal end, a distal end, a lumen therebetween, and a longitudinal axis,
• wherein the hollow needle is attached to the barrel via a generally tubular needle hub extending from the distal end of the barrel, said generally tubular needle hub having disposed about its external surface a plurality of ribs adapted to join the collar to the generally tubular needle hub;
• wherein each rib of the plurality of ribs includes a region having a first radial extent distal of the distal end of the barrel and a second radial extent distal of the first radial extent,
• wherein the second radial extent is greater than the first radial extent;
• further wherein the collar is adapted to be slidably received within the elongate generally tubular needle shield and to be prevented from being withdrawn proximally therefrom.