Investigation of the styloid process length in a Greek population

Abstract

Background: The styloid process (SP) is a slender cylindrical bony projection of the temporal bone with 2 ligaments and 3 muscles attached to it. Symptomatic SP elongation is also referred to, as Eagle's syndrome. The aim of the present study is to investigate the distribution of the SP length in a young adult Greek population. Materials and methods: Moreover, we provide a comparison of the results by using two different methods for assessing SP elongation, as described in the literature. Finally, we explore the possibility of using orthopantomograms (OPGs), as a diagnostic aid by investigating inter-examiner, intra-examiner and inter-examination variability and we propose a limit for SP elongation measurable in OPGs. Results: The sample comprised 805 digital OPGs, taken from student pilots and engineers entering the Hellenic Air Force Academy, from 2008 onwards. Two measuring approaches were selected, one using the temporal bone, as a cranial landmark and the other, using the external auditory meatus. The end tip of the process was always the caudal landmark. The mean SP length was 28.42 ± ± 8.48 mm in males and 26.04 ± 7.69 mm in females, when measured from the temporal bone. The mean SP length was 38.35 ± 8.90 mm in males and 34.24 ± ± 8.63 mm in females, when measured from the external auditory meatus. The length of 30 mm is most commonly used as a starting point for SP elongation. In the total sample, 30.6% of the measured SPs exceeded the length of 30 mm. In males, 33.12% of the SPs were elongated; while in females the corresponding incidence was 20%. One hundred and nineteen (14.8%) SPs were not traceable. Conclusions: The SP is typically detectable and measurable in OPGs. An elongated SP should be kept in mind, since symptoms of elongation may overlap with clinical manifestations of temporomandibular joint disorders.

Relationship Between Styloid Process Size and the Skeletal Craniofacial Pattern: A Cross-Sectional Study

“…A strong statistical correlation (r= 0.767, p<0.001) was found between the length of the right (29.4 mm) and the left (29.1 mm) styloid processes. Our findings were consistent with other studies published [13,23,29]. Although there is no consensus regarding the presence of elongated styloid process and the affected side, most patients have unilateral complaints [3,[9][10][11][12].…”

“…Previous literature has shown that the concept of normality of the styloid process size is variable. Eagle documented an average length from 25 to 30 mm, but recent reports suggest different cut-off values [1,2,13]. In this study the mean styloid process size in males was 34.6 mm, which is relatively long.…”

“…The panoramic radiograph is a valuable and reliable tool for the styloid process length analysis, not only in qualitative but also in a quantitative way [13,23]. Additionally, it is considered a routine exam taken in almost every dental practice, as it is easy to collect; it eliminates the styloid process overlapping issue that frequently occurs in cephalograms and it has a much lower radiation dose and lower cost than CT or CBCT, which are considered the gold standard for diagnosis of the elongated styloid process [6,12,23].…”

“…This sexual dimorphism is probably due to the higher stature of males in comparison to females [30]. The gender distribution is controversial in the literature: some authors found a higher prevalence of elongation in males, others found it in females and others found no significant differences [8][9][10][11][12][13]29]. This variation is suggestive that gender might be an irrelevant aspect in the etiology of styloid process elongation.…”

“…Mineralization of the stylohyoid process or stylohyoidstylomandibular ligament complex is a quite common anatomical finding [8]. Its prevalence is highly variable, due to true differences in the populations, or differences in the measurements criteria [6,[8][9][10][11][12][13]. Studies based on analysis of panoramic radiographs in various populations have shown a prevalence of 1% to 84.4% [6,[8][9][10][11][12][13].…”