Fig. 2.

Cephalometric distances. Reference diagram for cephalometric distances at the skull base and sinonasal cavity. ( A ) a: Planum height; b: sphenoid sinus height—between the sphenoid floor and the planum; c: distance between the sphenoid floor to the base of the sella turcica. ( B ) d, e: Depth of the olfactory fossa; f, g: width of the middle turbinates; h, i: distance between the orbital struts and the septum; j, k: distance between the lamina papyracea and the midline cribriform. ( C ) m: Maximum width of the pyriform aperture. ( D ) l: Maximum septal deflection from the midline at the deepest part of the cribriform plate.