Computational fluid dynamics analysis of the upper airway after rapid maxillary expansion: a case report

Progress in Orthodontics

Table 1 Definition of airway boundaries

	Anterior boundary	Posterior boundary	Superior boundary	Inferior boundary
Nasal cavity	Line connecting the ANS to the tip of the nasal bone	Line extending from S to the PNS	Line connecting N to S	Line extending from ANS to PNS
Nasopharynx	Line extending from S to the PNS	Line extending from S to the tip of the odontoid process	Line extending from S to the tip of the odontoid process	Line extending from PNS to the tip of the odontoid process
Oropharynx	Line extending from PNS to the tip of the epiglottis	Line extending from the tip of the odontoid process to the posterior superior border of CV4	Line extending from PNS to the tip of the odontoid process	Line extending from the base of the epiglottis to the posterior superior border of CV4
Hypopharynx	Line extending from the base of the epiglottis to the inferior border of the symphysis	Line extending from the posterior–superior corner of CV4 to the posterior–inferior corner of CV4	Line extending from the base of the epiglottis to the posterior superior border of CV4	Line extending from the posterior–inferior corner of CV4 to the inferior border of the symphysis

ANS anterior nasal spine, PNS posterior nasal spine, S sella, N nasion, CV cervical vertebrae