Sagittal and coronal dimensions of the ethmoid roof: a radioanatomic study.
BACKGROUND
Understanding the anatomy of the ethmoid roof is critical to safe surgical outcomes. Normative data regarding the height and slope of this region have been somewhat limited, derived primarily from cadaveric coronal computed tomography (CT) studies. With triplanar imaging programs, precise multidimensional measurements of the ethmoid roof are now possible. We present a radioanatomic study to characterize normative sagittal and coronal dimensions of the ethmoid roof.


METHODS
Bilateral measurements were taken in 100 consecutive sinus CT scans using ThinClient 3D software. In the sagittal plane, the height of the ethmoid roof was measured in quadrants at five equidistant points between the frontal beak and sphenoid face, referencing the nasal floor. In the coronal plane, the ethmoid roof was measured at three points at the level of the anterior ethmoid artery and at two points at the junction of the posterior ethmoid and sphenoid sinuses.


RESULTS
When examined sagittally, the right side showed significantly lower skull base heights in the anterior ethmoid compared with the left side (59.0 mm versus 59.8 mm, p = 0.017; 53.7 mm versus 54.5 mm, p = 0.0004). Coronal measurements of the anterior ethmoid roof showed similar significant differences. The anterior ethmoid roof had greater asymmetries of height compared with the posterior ethmoid roof, which was fairly constant.


CONCLUSIONS
This study provides numerical correlates to accepted concepts regarding the shape and slope of the ethmoid roof. Differences in height of the skull base between right and left sides, especially in the anterior ethmoid sinus, may be an important surgical consideration. The posterior ethmoid roof appears to be relatively constant and should serve as a reliable surgical landmark.
Zacharek
Mark A
MA
Department of Otolaryngology-Head and Neck Surgery, Henry Ford Hospital, Detroit, Michigan, USA.
Han
Joseph K
JK
Allen
Robert
R
Weissman
Jane L
JL
Hwang
Peter H
PH
D000328:Adult; D005004:Ethmoid Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D013517:Otorhinolaryngologic Surgical Procedures / Q000379:methods; D012016:Reference Values; D012984:Software; D014057:Tomography, X-Ray Computed