The platelet rich plasma is separated from {TAIL ~ the residual red blood cells} in {HEAD ~ a first part} 
The platelet rich plasma is separated from { TAIL ~ the residual red blood cells } in { HEAD ~ a first part }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD