Objective: To assess the prevalence of pneumatization in Computed tomographic sections of normal patients.

Study design: Retrospective CT scans of 220 patients with no pathology in temporal bone were collected and examined for the prevalence of pneumatizationof temporal bone.Based on the extent of pneumatizationfrom mastoid cavity to articular eminence [AE]it was divided into 4 groups.

Results:Among 220 patients 180 (81%) patientsshowed pneumatization.In 180 sections grade I pneumatization was seen in highest number of scans 74(41%) followed by grade zero with 31% grade II with 24% and least in grade III with 4% .Prevalence of pneumatization was found to be highest on right side compared to left side.

Conclusion:Prevalence and extent of temporal bone pneumatization can be assessed using CT sections significantly.