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