Chulalongkorn Medical Journal


Background : Endoscopic sinus and anterior skull base surgery requires anatomicallandmarks to identify the location of each paranasal sinus. Even thoughmany anatomical reference points are applied, they can be distorted bytumors, inflammatory processes and previous surgeries. An earlier studyof the paranasal sinus in computed tomography found that the maxillaryroof (orbital floor) represented a reliable fixed anatomical landmark duringthe endoscopic dissection for the entry of the sphenoid sinus that avoidsthe skull base. However, the study in cadavers has never been performedand no comparative study between genders has been done.Objective : To determine the distance from nasal floor to cribriform plate, ethmoidroof, skull base, sphenoid floor and the orbital floor. A comparisonbetween genders was carried out.Methods : Thirty-nine hemisagittal Thai cadaveric heads were included in this study.Four parameters were measured as follows: the nasal floor to the lowestpoint of cribriform plate (A): the nasal floor to the highest point of ethmoidroof (B): the nasal floor to skull base at the anterior wall of sphenoidsinus (C): and the nasal floor to the floor of sphenoid sinus (D). Thedistance from the nasal floor to the highest point of the maxillary roof ororbital floor (E) was measured after removal of the lateral nasal wall.Results : Twenty female and nineteen male hemisagittal heads from 39 cadaverswere included in this study. The mean distances of A, B, C, D, and Ewere: 44.1 ± 4.4, 49.1 ± 4.7, 45.6 ± 5.1, 20.6 ± 3.2, and 32.4 ± 3.8 mm,respectively. The results revealed that the mean distance from the nasalfloor to orbital floor (E) was the shortest among those of A, B and C. Allorbital floors were lower than the cribriform plate, the ethmoid roof andthe skull base at a mean distance of 11.8 ± 4.4, 16.8 ± 4.7 and13.2 ± 4.2 mm, respectively. However, statistically significant differencebetween both genders were found in the distances from the nasal floorto the cribriform plate (A), the skull base (C) and the orbital floor (E).Conclusions : Direct cadaveric measurement in this study confirms the findings resultsof a previous CT study. Additional result was the statistically significantdifference between both genders in the distances from the nasal floor tothe cribriform plate (A), to the skull base (C) and to the orbital floor (E).


Faculty of Medicine, Chulalongkorn University

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