Gender and the lateral angle of the internal acoustic canal meatus as measured on computerized tomography of the temporal bone

Introduction: Cadaveric studies yielded promising results in sexing the temporal bones by measuring the lateral angle of the internal acoustic canal meatus. In this study, we evaluated the capability of computerized tomography of the temporal bone to reproduce these results. Methods: Lateral angle of the internal acoustic canal meatus was measured in 92 patients (47 females and 45 males) on axial slices of high resolution computerized tomography scans of the temporal bone. The patients underwent computerized tomography as part of clinical work up for ear-related complaints. The measurement technique was modified from a cadaveric study in which a significantly higher mean lateral angle measurement was observed in females than in males. The mean values from females and males were compared statistically. Results: The mean lateral angle as measured on computerized tomography of the temporal bone is greater in females (45.5 +/- 7.1 degrees) than in males (41.6 +/- 6.7 degrees). The difference is significant at p < 0.01, as tested by one-way ANOVA. Due to significant overlap in ranges of measurements, no single cut-off value that satisfactorily differentiates between the genders could be determined. However, measurements of 35 degrees and lesser were 93.6% specific for male gender and measurements of 60 degrees and greater were 97.7% specific for female gender. Conclusion: Computerized tomography of the temporal bone is capable of replicating the results front the cadaveric measurements in determining the lateral angle. Due to the large range of measurements within both genders, this measurement should be regarded as supportive and not conclusive evidence for the sex of the subject. (C) 2008 Elsevier Ireland Ltd. All rights reserved.