In one embodiment, the fourchette extends to the edge of {HEAD ~ an opening} formed by the fourchette and {TAIL ~ the anterior and posterior portion} 
formed by
In one embodiment , the fourchette extends to the edge of { HEAD ~ an opening } formed by the fourchette and { TAIL ~ the anterior and posterior portion }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL