In {HEAD ~ a further preferred aspect} of {TAIL ~ the present invention}, the elongate penetrating element is a needle, having a retractable obturator at its distal end 
of
In { HEAD ~ a further preferred aspect } of { TAIL ~ the present invention } , the elongate penetrating element is a needle , having a retractable obturator at its distal end
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH