Investigation of the styloid process length in a Greek population.

The styloid process (SP) is a slender cylindrical bony projection of the temporal bone with two ligaments and three 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. 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 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 orthopantomograms (OPGs). The sample comprised of 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,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 30mm. In males, 33.12% of the SPs were elongated; while in females the corresponding incidence was 20%. An amount of 119 SPs (14.8%) were not traceable. 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.