The importance of medial-lateral styloid process angulation/coronal plane angle in symptomatic eagle syndrome.

We used three-dimensional computerized tomography (3DCT) to obtain images of Eagle Syndrome (ES) cases and measurements of relevant variables. Twenty-five subjects with ES and 25 controls were included in this retrospective study. Styloid process length, anterior-posterior styloid process angulation (Sagittal plane angle) (APA), medial-lateral styloid process angulation (Coronal plane angle) (MLA), tonsil-stiloid distance and carotid-stiloid distance were measured on CT and 3DCT images, and cranial and neck angiography was obtained, from a total of 580 images. The styloid process lengths were 40.3 and 40.5 mm on the right and left sides in the ES group. The left MLA was lower in symptomatic (Median: 67.0°) than asymptomatic (Median: 72.6°) ES patients. In ES patients with styloid process length above 3 cm, MLA (coronal plane angle) is important, and the symptoms are more intense when this angle is smaller. Clin. Anat. 30:487-491, 2017.