Complications of mandibular angle contouring may include damage to the inferior alveolar nerve. This study was undertaken to quantify the path of the inferior alveolar nerve in the normal human mandible and in the mandibles of patients presenting for cosmetic reduction of the mandibular angles. The study was based upon the panorama radiography of 20 normal population (ten men, ten women) and 20 patients (ten men, ten women) complaining of square face. Using panorama radiographs and paper tracing, the distance from the "A" point (Fig. 1) to the inferior alveolar nerve was recorded within its mandibular osseous canal in the mandibular angle. The nerve was identifiable in each ramus. The average distance between A　point and the other points along the osseous canal is 21.48mm. Therefore together with an additional margin of several millimeters, it is important to maintain a safe distance of at least an inch (25mm) between the saw and the anterior border of the ramus. From our clinical experiences, we are suggesting that this "1 inch maneuver" to be very helpful in avoiding injury to the inferior alveolar nerve, especially for the novice surgeon.