When the surgeon determines which of {HEAD ~ the surgical instrument holders} 10, 40, 50 is required for a given surgical procedure, {TAIL ~ the surgeon} selects one or more packages 36 containing the holders 10, 40, or 50 
When the surgeon determines which of { HEAD ~ the surgical instrument holders } 10 , 40 , 50 is required for a given surgical procedure , { TAIL ~ the surgeon } selects one or more packages 36 containing the holders 10 , 40 , or 50
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH