BONY VARIATIONS ON CORONARY CT CUTS OF TH E PARANASAL SINUSES

Bony variations in the anterior ethmoids may, if severe, play an impor tant role in the development of chronic sinusitis and present the surg eon with added risks during operation. We have, therefore, analysed 39 0 preoperative CT examinations of the sinuses performed in the coronar y plane with respect to the frequency of bone variations. Concha bullo sa, increased pneumatisation of the agger nasi, large ethmoidal bullae , Haller's cells and increased pneumatisation of the sphenoid were fou nd with equal frequency in about 20%. The most common variants occurre d in the uncinate process (31.5%), less common were paradoxical curve of the middle turbinates (13.3%) and very rare were Onodi cells (1.3%) .