ABSTRACT
Background: Ethmoid Skull Base (ESB) is anarticulation of ethmoid roof with Lateral Lamella ofCribriform plate (LLCP). An increased LLCP heightwas observed to increase the vulnerability of ESB tosurgical injuries. Aim and Objectives: The present studywas undertaken to analyze the configuration of thelateral lamella of cribriform plate, the ethmoid roof withrespect to Keros type of olfactory fossa. Material andMethods: Aretrospective Computed Tomographic (CT)study was done with 60 Coronal Paranasal Sinuses(PNS) scans and LLCP height was determined bysubtracting Medial Ethmoid Roof Point (MERP) fromCP heights and classified according to Keros. Thedifference between Medial Ethmoid Roof Point(MERP) and Lateral Ethmoid Roof Point (LERP)heights in both anterior and posterior planes indicatesthe direction of ethmoid roof slope. Results: Theaverage height of the LLCP was between 1.53 to 8.55mm with a mean (SD) of 3.77 mm 1.66 and majoritybelonged to Keros type I. Overall mean differencebetween LERP and MERP was 5.43 0.74 mm inanterior and 4.43 0.63 mm in posterior planes. In boththe planes irrespective of the sides the height of theLERPwas higher in relation to medial side. Conclusion:Keros type I was the most common type and the slope ofanterior ethmoid roof is steeper compared to posterior.This preoperative knowledge about the configuration ofLLCPas well as the ethmoid roof contour is vital duringendonasal ethmoidal surgeries.