Assessment of the lingual nerve in the third molar region using magnetic resonance imaging

Purpose: The purpose of this study was to determine the precise in situ location of the lingual nerve in the third molar region using high-resolution magnetic resonance imaging. Patients and Methods: Ten healthy volunteers (20 sides) with mandibular third molars underwent bilateral axial and coronal high-resolution magnetic resonance imaging (MRI) examinations of the posterior mandible and floor of the mouth from the lingula to the mental foramen. Three trained individuals made measurements of each image to determine the vertical and horizontal position of the lingual nerve in the third molar region. Results: The mean vertical (2.75 +/- 0.97 mm [range, 1.52-4.61]) and horizontal (2.53 +/- 0.67 mm [range, 0.00-4.35]) distances to the lingual crest and lingual plate of the mandible were determined. In the third molar region, there were only 2 of 20 cases (10%) in which the nerve was above the lingual crest, and there were 5 of 20 instances (25%) in which the nerve was in direct contact with the lingual plate. Conclusions: This study precisely documents the in situ location of the lingual nerve in the third molar region, and reconfirms the relative vulnerable position of this structure during third molar surgery.