A hollow plastic dilator 60 is then passed through {HEAD ~ passage} 11 of the cannula housing and is slid over {TAIL ~ guide} 61 
A hollow plastic dilator 60 is then passed through { HEAD ~ passage } 11 of the cannula housing and is slid over { TAIL ~ guide } 61
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH