Postoperative changes in the pharyngeal airway space through computed tomography evaluation after mandibular setback surgery in skeletal class III patients: 1-year follow-up

Maxillofacial Plastic and Reconstructive Surgery

Table 3 Pharyngeal airway measurements

Measurements	Definition
Nph AP	Nasopharyngeal airway distance, anteroposterior distance at CV₁ level
Oph AP	Oropharyngeal airway distance, anteroposterior distance at CV₂ level
Hph AP	Hypopharyngeal airway distance, anteroposterior distance at CV₄ level
Nph vol	Nasopharyngeal airway volume, top of the pharyngeal airway to CV₁ plane
Oph vol	Oropharyngeal airway volume, between the CV₁ plane and CV₂ plane
Hph vol	Hypopharyngeal airway volume, from CV₂ plane to CV₄ plane
Whole pharynx volume	Sum of the Nph volume, Oph volume, and Hph volume
SV-B	The distance from the sella vertical plane to the B point