Endoscopic localization of the anterior and posterior ethmoid arteries.

OBJECTIVES: Understanding the endoscopic locations of the anterior and posterior ethmoid arteries is important during endoscopic sinus or endoscopic skull base procedures so that these arteries can be avoided. Therefore, the objective of this study was to define the endoscopic locations of the ethmoid arteries. METHODS: Twenty-four cadaver heads were used to identify the endoscopic location of the ethmoid arteries via an external incision. An image guidance system was used to record the locations of these arteries. The anterior ethmoid artery was referenced to the axilla of the middle turbinate, and the posterior ethmoid artery to the anterior wall of the sphenoid sinus. The closest lamella to these arteries was identified. RESULTS: Forty-eight nasal cavities were dissected. The mean distance from the axilla to the anterior ethmoid artery was 17.5 mm. The anterior ethmoid artery was located immediately anterior to (31%), at (36%), or immediately posterior to (33%) the superior attachment of the basal lamella. The mean distance from the posterior ethmoid artery to the anterior ethmoid artery was 14.9 mm. The mean distance from the posterior ethmoid artery to the anterior wall of the sphenoid sinus was 8.1 mm. The posterior ethmoid artery was either anterior to (98%) or at (2%) the anterior face of the sphenoid sinus. CONCLUSIONS: Specific endoscopic anatomic relationships and measurements have been presented for the anterior and posterior ethmoid arteries.