Joints between the fourchette and the anterior and posterior portions maintain {HEAD ~ an opening} formed by {TAIL ~ the cuff} in an open position 
Joints between the fourchette and the anterior and posterior portions maintain { HEAD ~ an opening } formed by { TAIL ~ the cuff } in an open position
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH