Figure 5

Cephalometric landmarks (numeric) and planes (capital letter) used for posterior airway evaluation. 1) S: sella turcica; 2) Se: sphenoethmoidal junction; 3) N: nasion; 4) Ba: basion; 5) Ptm: pterygomaxillary fissure; 6) PNS: posterior nasal spine; 7) A: A-point, subspinale; 8) P: ate, the most inferior tip of the soft palate; 9) Mo: posterior contact point of the molar; 10) PreM: contact point of the premolar;11) Tt: tip of the tongue; 12) B: B-point, supramentale;13) Go: gonion; 14) Gn: gnathion; 15) Me: menton; 16) H: hyoidale; 17) Eb: base of the epiglottis; 18) PhwS: superior posterior pharyngeal wall; 19) Psp: posterior-superior palate, the most posterior-superior point of the soft palate; 20) PhwN: posterior pharyngeal wall at narrowest point; 21) STBn: most anterior point in the airway on the soft palate; 22) PhwI: inferior posterior pharyngeal wall; 23) STBi: most anterior point in the airway on the tongue; A) VAL = PNS to Eb; B) TL = Eb to Tt; C) S-PAS = PhwS to Psp; D) N-PAS = PhwN to STBn; E) I-PAS = PhwI to STBi; F) H-MP: H to mandibular plane; G) PM: extends down from SE point through the inferior point of PTM; H) NOA: neutral occlusal axis, perpendicular to PM through the posterior-inferior-most contact point of the last fully erupted maxillary molar; I) FOP: functional occlusal plane.