Abnormal Length of the Styloid Process: An Anomaly Underestimated of the Temporal Bone with Surgical and Clinical Relevance

Abstract

Objective: We conducted an osteometric study in humans on styloid process of temporal bone to determine the average length and the frequency of a process excessively long that can cause unrecognized cerebrovascular syndromes or a form of neuralgia of the glossopharyngeal nerve: “Eagle syndrome.” Study Design: Measurement of styloid process was conducted on a significant part of the entire collection of skulls which showed the whole process. To highlight differences in the length of the process related to sex we have divided the skulls in two different groups by gender. Material and Methods: We measured the length of the styloid process by a digital caliper on a sample of 153 dried skulls of local museum “Leonetto Comparini.” Data was analyzed through statistical software (Salstat2, Sourceforge, Dice Holdings Inc.): average and standard deviation (SD) were calculated. A t-test was applied to the means of the two groups different for sex. Results: The average length of styloid process is 27 mm. The range of normality (average + 2st) was 42 mm. An abnormal long styloid process > 42 mm is present in 6% of items. The greatest length observed for the styloid process was 52 mm. In one case of a stylohyoid calcified ligament the styloid process was long length being 70 mm. The difference between the averages of different groups by sex was not significant. Conclusion: The presence with a certain frequency of an elongated styloid process must lead to find out this anomaly radiologically in the case of suspected “Eagle syndrome.”