Fig. 3

Reference lines. Eight white lines were determined based on the study by Perry [15]. Sella-Nasion (SN) was used as the standard, and eight linear measurements are shown. Velar depth = VD, velar height = VH, retroglossal space = RS, laryngeal ventricle space = LVS, laryngeal ventricle-sphenoid sinus length = LVSL, hard-palate length = HPL, lingual apex-pharyngeal length = LAPL, lingual apex-hard palate length = LAHL. And six measurements for face size. N = Nasion, Ba = Basion, S = Sella, ANS = anterior nasal spine, PNS = posterior nasal spine, Me = Menton