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