{HEAD ~ The funnel shaped occlusion balloon} seals {TAIL ~ the walls} of the vessel to establish retrograde flow of blood 
seals
{ HEAD ~ The funnel shaped occlusion balloon } seals { TAIL ~ the walls } of the vessel to establish retrograde flow of blood
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH