Figure 1.

(A) Delimitation of the pharyngeal space in the sagittal view: the upper limit includes the glandular soft palate, the region above the adenoid pad and the choanae, representing the roof of the nasopharynx (a), the anterior limit is defined as a plane perpendicular to the sella-nasion line passing through the point of transition between the hard and the soft palate (b), the inferior limit was a horizontal plane passing from the most anterior and inferior point of C3 (c), and the posterior limit was a plane perpendicular to the sella-nasion tangential to the posterior pharyngeal wall (d). (B) and (C) show the corresponding limits in the axial and coronal views, respectively.