Table 1.
Anatomical and Technical Limits of the Upper Airway
| Limit |
Anatomical |
Technical |
| Superior | Hard and soft palate | The line passing from the palatal plane (ANS to PNS) extending to the posterior wall of the pharynxa |
| Inferior | Vallecula (plane of hyoid bone; base of the epiglottis) | Line passing from the antero-superior edge of C4 to menton |
| Anterior | Circumvallate papillae and the oropharyngeal isthmus | Line passing from the soft palate to menton |
| Posterior | Respective pharyngeal walls | Posterior wall of the pharynx |
| Lateral | Respective pharyngeal walls | Respective pharyngeal walls |
a
ANS indicates anterior nasal spine; PNS, posterior nasal spine.