The frontal wishbone: Anatomic and clinical implications

Background: The interfrontal septal cell, which often takes the shape of a wishbone on axial CT scan, was first described by Van Alyea more than 50 years ago; however, its potential role in disease of the frontal sinus was only recently recognized. The purpose of this study was to correlate the incidence and dimensions of this "frontal wishbone" (FWB) with the presence of frontal sinus disease. Methods: The dimensions, drainage pathways, and disease state of the FWB were measured in 150 consecutive sinus CT scans performed at a tertiary care referral center. Statistical analysis was performed to correlate the FWB configuration to the presence of frontal sinus disease. Results: A FWB was present in 77.3% of patients. The wishbone drained through a discrete ostium into either the left (54.8%), the right (45.2%), or the bilateral (0.8%) frontal sinuses. In those scans with mucosal thickening or opacification of the frontal sinus (36%), concurrent FWB disease was found in 82%. Patients with a large (>1 cm) FWB in the anterior-posterior dimension were more likely to have a diseased frontal sinus (p = 0.02). Conclusion: The term FWB is used to describe an air cell within the interfrontal septum, which may play a role in the pathogenesis of frontal sinus disease.