An anatomic study of the horizontal petrous internal carotid artery: sex and age differences.

OBJECTIVE This study aimed to determine the length and diameter of the horizontal portion of the petrous carotid artery (HPCA) and to evaluate sex and age differences in these variables. METHODS We examined standard axial sinus computed tomographic images in 345 patients (690 sides), measuring length and diameter of the HPCA and the angle between right and left HPCA using computer software. RESULTS The HPCA averaged 26.7 mm in length and 5.7 mm in diameter. The angle between the right and left HPCA averaged 101.5 degrees . HPCA length averaged 27.1mm in men and 25.8mm in women; HPCA diameter averaged 5.9 mm in men and 5.3 mm in women. The HPCA of men was approximately 0.8 mm wider and the angle between right and left HPCA was on average 8.7 degrees more obtuse in the 60+ years group than in the <or=19 years group. The HPCA of men was approximately 1.0mm shorter in the 60 years+ group than in both the 20-39 years group and the 40-59 years group. CONCLUSIONS Length, diameter and angle of the HPCA exhibited significant sex differences. Aging affected the HPCA in men. This information may be very important not only for surgery of the petrous region or middle fossa but also for anthropological investigation.