NF = nasal floor level: most anterior (nfa) and posterior (nfp) point in the sagittal plane, the most right (nfr) and left (nfl) point.
V = velum level: the most anterior (vam) and posterior (vmp) point in the sagittal plane, the most anterior (var) and posterior point (vpr) in the right part, the most anterior (val) and posterior point (vpl) in the left part.
RL = radix linguae level: most anterior (rla) and posterior point (rlp) in the sagittal plane, the most right (rlr) and left (rll) point.
EP = epiglottis level: most anterior (epa) and posterior point (epp) in the sagittal plane, the most right (epr) and left (epl) point.
HY = hyoid bone level: most anterior (hya) and posterior (hyp) point in the sagittal plane, the most right (hyr) and left (hyl) point.