In an embodiment, {HEAD ~ the region} 38 has depth greater than {TAIL ~ the region} 34 
In an embodiment , { HEAD ~ the region } 38 has depth greater than { TAIL ~ the region } 34
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH