Radiological study of the intumescentia septi nasi anterior.

Intumescentia septi nasi anterior (ISNA) is a common anatomical variation that is not routinely noticed by surgeons or radiologists. ISNA is a mucosal bulging located on each side of the anterior part of the septum. The aim of this study was to investigate the prevalence of ISNA in different ages and sexes. In this study, computerized tomography (CT) scans of the paranasal sinus were obtained from 595 patients who had symptoms of chronic sinusitis. Among 595 subjects, ISNA was found in 332 (55.79 per cent) of subjects. It was found more frequently in males than females in every age group. Although ISNA is a common anatomical variation, it is generally overlooked. This is the first report on ISNA in different age groups and sexes.