Variations in the Anatomical Location of the Mandibular Foramen

Ciavaglia, Marco, Ibrahim Aljerdi, Adam Elturk, and Mary Tracy-Bee

The inferior alveolar nerve courses through the mandibular foramen, where it is typically targeted in anesthesia of the lower jaw. In numerous dental operations, it is common for inferior alveolar nerve blocks to not have a perfect success rate. This is believed to be a result of the variation in the position of the mandibular foramen anatomically. The aim of this study was to determine the location of the mandibular foramen in relation to the typically used landmarks on the mandibular ramus in both African American and Caucasian patients. Using digital photographs of skulls from the Hamaan-Todd collection at the Cleveland Museum of Natural History, measurements were taken on 5 anatomical structures in the mandibular ramus. The study was performed using 146 dried mandibles with about half being Caucasian and the other half being African American. Each of those were then split into about half males and half females. Measurements of the mandible included distance from the center of the mandibular foramen to locations on the ramus such as the anterior border, posterior border, mandibular notch, and the mandibular angle and from the condyle to the coronoid process to see if there was any relation there as well. Mandibles were measured using Adobe Photoshop CS6 and statistically analyzed using SPSS. For the condyle to coronoid process, measurements were taken from the highest points of each going across. All measurement were normalized for the height of the skull. A significant difference was identified in the antero-posterior foramen position between African-American and Caucasian populations (p=0.028), with the foramen lying more anterior in African-American skulls. A significant difference was also found in the supero-inferior position of the mandibular foramen with it lying more superior on the mandibular ramus of females relative to males (p=0.043). A significant difference was not identified in the distance between the condyloid and coronoid process (p=0.764). This has great clinical relevance as it may result in variable treatment and positioning of anesthesia needles in patients of different races.