Correlation of Lateral Cephalogram and Flexible Laryngoscopy with Sleep Study in Obstructive Sleep Apnea

Figure 1

Standard lateral cephalogram with markings for SNA, SNB, PAS, MP-H, and PNS-P. Angle SNA: the angle from sella at the centre of pituitary fossa of sphenoid bone to nasion and the most posterior point on the curve between anterior nasal spine and supradentale of the maxilla. Angle SNB: the angle from sella, nasion, and the point of greatest concavity on the anterior surface of mandibular symphysis. PAS (posterior airway space): the distance from base of tongue to the posterior pharyngeal wall at the level of C2 vertebra. PNS-P (length of the soft palate): the distance from the most posterior point on the sagittal plane of hard palate (PNS) to the tip of the soft palate (P). MP-H (mandibular plane to hyoid bone): measured at the mentum (Me) as the line joining MP (mandibular plane) to H (the most anterosuperior point of the hyoid bone). MP: the line joining (Me) and Go (Gonion, most lateral external point at the junction of the horizontal and ascending ramus of the mandible).