The surgeon's view of the anterior ethmoid artery

OBJECTIVES: To define the relationship of the anterior ethmoid artery to the frontal recess and secondly whether the degree of pneumatisation of the suprabullar recess/supraorbital cell correlates with the distance between the anterior ethmoid artery and the skull base thus making it more vulnerable to damage during surgery. METHOD: Thirty-four cadaver head sides were perfused with pink latex. All specimens had high-resolution computed tomography (CT) scans using bone windows in the axial, coronal and sagittal planes. The specimen's nasal septum was removed and the ethmoid sinuses dissected to locate the anterior ethmoid artery. Calipers were used to measure distance between the artery and the frontal recess and from the skull base. RESULTS: The anterior ethmoid artery was found in all the specimens and scans. The distance between the anterior ethmoid artery and the posterior wall of the frontal recess was 11 mm (range 6-15 mm). In all specimens, the artery was seen between the second and third lamella. The commonest location of the artery was in the suprabullar recess (85.3%). Supraorbital cells were seen in 16 specimens. The ethmoid sinuses were well pneumatised with a large supraorbital cell in 10 of these specimens and in these the artery was lying 3.7 mm (range 1-8 mm) away from the skull base. Six specimens had poor pneumatisation and a small supraorbital cell and in these the artery was found close to or with in the skull base. In specimens without a supraorbital cell, the artery lay at the skull base in all but one. CONCLUSIONS: The position of the anterior ethmoidal artery is very variable. The artery is found between the second and third lamella. When the ethmoid sinuses are more pneumatised and in particular when there is a supraorbital cell, the artery lies below the skull base. A good strategy is to identify the degree of pneumatisation of the ethmoid sinuses from CT scans preoperatively to see if the artery is at an increased risk of being damaged.