Ostial obstruction is a primary pathophysiological mechanism contributing to sinusitis, which can be caused by anatomical variations, mucosal inflammation or both. This retrospective case series aimed to identify anatomical factors and inflammatory areas relating to chronic frontal sinusitis on nasal / paranasal CT scans. 240 sides of CT scans in adult patients with chronic rhinosinusitis underwent logistic regression analysis to compare distribution of various frontal recess cells and surrounding inflammatory conditions in patients with and without sinusitis. Opacification of the frontal recess and sinus lateralis was found to be associated with a significantly increased risk of frontal sinusitis and developing blockage of drainage pathways – evidence that mucosal inflammation in these two areas is an important factor in leading to chronic frontal sinusitis. They also showed that the presence of septal deviation and suprabulbar cells tended to correlate with a higher frequency of frontal sinusitis, although there was no significant association between these anatomical factors and the presence of frontal sinusitis. The patients with frontal sinusitis also had shorter AP diameters of the frontal ostium and frontal recess in comparison to those without frontal sinusitis. These findings highlight the potential role of anatomy of the frontal sinus drainage pathways to the development of chronic frontal changes.