Length of the styloid process and anatomical implications for Eagle's syndrome

Abstract

The styloid process is a bony projection, located just anterior to the stylomastoid foramen, the normal length of which is approximately 20-25 mm. Elongation of the process may cause various clinical symptoms such as neck and cervicofacial pain, described as Eagle's syndrome. The present study aimed to determine the mean length of the styloid process on cadavers, panoramic radiographs, and dry skulls, and to investigate the incidence of the elongated styloid process, while assessing the elongation in relation to Eagles syndrome. When the measurements from the panoramic radiographs were assessed, the mean length of the styloid processes in males and females on the right and left sides were found to be the following: 25.78 +/- 5.68 mm; 22.69 +/- 3.68 mm, 25.80 +/- 5.75 mm; and 22.75 +/- 3.65 mm, respectively. The males had greater styloid process lengths than the females, and the differences in length on both the right and left sides were statistically significant. Descriptive statistics and comparison results according to age groups were determined. There was no statistically significant difference between right or left styloid process lengths according to age groups. The mean length of the styloid process of the cadavers and dry bones was 22.54 +/- 4.24, and there was no significant difference between the right and left sides of the cadavers and dry bones. The incidence of the elongated styloid process was determined as 3.3%, and the elongations revealed a female dominance. The average length of the elongated styloid process was 36.06 +/- 6.12 mm, while the mean length of the styloid processes of the subjects reporting Eagle's syndrome was 40 +/- 4.72 mm. The results of this morphological study will assist clinicians in the diagnosis of Eagle's syndrome. (Folia Morphol 2009; 68, 4: 265-270)