Table 1 Definitions of the paranasal sinus anatomic variations

Frontal sinus hyperpneumatization

significant extension to the orbital plate and squamous part of the frontal bone

Frontal sinus hypoplasia

Sinus is devoid of pneumatization more than 6 mm in anteroposterior direction with not much extension to the squamous part of the frontal bone

Interfrontal sinus septa cells

pneumatization of the frontal sinus septum

Agger nasi cells

the most anterior ethmoid cells extramural migration to the frontal process of the maxilla

Supraorbital ethmoid cells

anterior ethmoid cells extending to the roof of the orbit and located behind the posterior wall of the frontal sinus

Crista galli pneumatization

air cavity in crista galli most commonly coming from the frontal sinus

Inferior concha bullosa

air filled cavity in the inferior turbinate

Haller cell

posterior ethmoid cells extramural migration to the floor of the orbit and roof of the maxillary sinus near ostium

Concha bullosa

air filled cavity of the middle turbinate

Uncinate bulla

pneumatization of the uncinate process

Secondary middle turbinate

accessory middle concha

Maxillary sinus hypoplasia

when the maximum horizontal or vertical diameter is less than half of the maximum orbital diameter.

Superior concha bullosa

air filled cavity in the superior turbinate

Secondary superior concha

accessory superior concha

Ethmomaxillary sinus

enlarged posterior ethmoid cells located over the maxillary sinus and draining into the superior meatus

Sphenomaxillary plate

bony plate lying between the maxillary and sphenoid sinus, triangular in shape

Septum deviation

developmental or acquired deviation in nasal septum

Septum pneumatization

pneumatization of the nasal septum

Internal carotid artery (ICA) bulging

projection of the ICA into the sphenoid sinus

Onodi cell

posterior ethmoid cell located in the anterosuperior portion of the sphenoid sinus and closely related to the optic nerve

Anterior clinoid pneumatization

air filled cavity in the anterior clinoid process

Posterior clinoid pneumatization

air filled cavity of the posterior clinoid process

Pterygoid pneumatization

extensive pneumatization of the sphenoid sinus which passes over the line between the foramen rotundum and Vidian canal