Styloid Process: What Length Is Abnormal?

Abstract

The length of the styloid process varies greatly in different populations and depends on ethnicity and geographical background. The elongated styloid process may be associated with Eagle’s syndrome. Therefore, the mean normal length of the styloid process in different population groups needs to be calculated and the upper cutoff limit for elongated styloid process should be found. The objective of the research was to evaluate the styloid process length in the Kashmiri population using multidetector computed tomography. Materials and Methods. We retrospectively evaluated 304 patients who underwent computed tomography of the head and paranasal sinuses, and the mean styloid process length was calculated on both sides. The mean of three measurements of styloid process length was taken. The study population was grouped as follows: Group I included patients at the age of 21-30 years; Group II comprised patients at the age of 31-40 years; Group III included 68 patients at the age of 41-50 years; Group IV comprised patients > 50 years old. Results. The mean length of the styloid process in the studied population varied from 20 to 51 mm (mean 31.3 ± 4.5 mm). There was no significant difference in the length on both sides (p=0.835). The mean length of the styloid process was 30.1 ± 4.2 mm in females and 32.3 ± 4.8 mm in males (p< 0.034). The lengths of the styloid process in different age groups were as follows: in Group I - 30.9 ± 4.4 mm; in Group II - 31.2 ± 4.8 mm; in Group III - 31.6 ± 4.3 mm; in Group IV - 31.5 ± 4.5 mm. Conclusions. The mean length of the styloid process in our population was higher as compared to many other ethnic groups. The styloid process in males was longer. The elongated styloid process on computed tomography scan should not be labeled as Eagle’s syndrome unless clinical symptoms are present.

Keywords

• styloid process
• computed tomography
• eagle's syndrome
• shaded surface display