Thus, a gas may be delivered from a gas source through the gas tubing, swivel coupling, and {HEAD ~ cannula} to a patient without tangling or twisting {TAIL ~ the tubing} 
Thus , a gas may be delivered from a gas source through the gas tubing , swivel coupling , and { HEAD ~ cannula } to a patient without tangling or twisting { TAIL ~ the tubing }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL