A Clinical and Anatomical Study on the Mandible for Inferior Alveolar Nerve Conductive Anesthesia in Korean

This study was to investigate the various parts of the mandible related to inferior alveolar nerve conductive anesthesia in 228 dry skulls of Korean adults. Five morphological variations were observed and four measurements were undertaken. The following results were obtained. 1. The Position of coronoid notch in the anterior border of the ramus of mandible is classified into three types and percentage of each type was as follows : Type I (Coronoid notch in the middle part of the anterior border of the ramus of mandible) : 83.3% Type II (Coronoid notch in the inferior part of the anterior border of the ramus of mandible) : 12.7% Type III (No coronoid notch in the anterior border of the ramps of mandible) : 4.0% 2. The position of the lingula of mandible to the imaginary line of the molar occlusal plane is classified into three types and percentage of each type was as follows : Type I (Above the imaginary line of the mandibular molar occlusal plane) : 87.3% Type II (Coincide with the imaginary line of the mandibular molar occlusal plane) : 8.6% Type III (Below the imaginary of mandibular molar occlusal plane) : 4.3% 3. The position of the lingula of the mandible in the internal oblique line-posterior border of the ramus of mandible dimension is classified into three types and percentage of each type was as follows : Type I (Anterior part in the internal oblique line-posterior border of the ramus of mandible dimension) : 82.9% Type II (Middle part in the internal oblique line-posterior border of the ramus of mandible dimension) : 11. 4% Type III (Posterior part in the internal oblique line-posterior border of the ramus of mandible dimension) : 5.7% 4. The position of the apex of the lingula of mandible to the deepest point of the coronoid notch in the anterior border of the ramus of mandible is classified into three types and percentage of each type was as follows : Type I (Coincide with the deepest point of the coronoid notch) : 82.0% Type II (Above the deepest point of the coronoid notch) : 13.2% Type III (Below the deepest point of the coronoid notch) : 4.8% 5. The position of the apex of the lingula of mandible to the imaginary line of the mandibular molar occlusal plane is classified into three types and percentage of each type was as follows : Type I (Above the 8mm) : 65.7% Type II (Above the 5mm) : 18.6% Type III (Above the 10mm) : 15.7% 6. Angle between the line connecting the apex of the lingula of mandible-1-2 premolars in the contralateral side and median line of the mandible is classified into three types and percentage of each type was as follows : Type I (50°) : 67.2% Type II (45°) 21.4% Type III (55°) : 11.4% 7. The averages of the measurement of the various bony landmarks of the mandible related to inferior alveolar nerve conductive anesthesia were as follows : ① Distance from deepest point of the coronoid notch to internal oblique line : 9.2mm ② Distance from internal oblique line to the apex of the lingula of mandible : 11.6mm ③ Distance from deepest point of the coronoid notch to apex of the lingula of mandible : 19.7mm ④ Height of the lingula of mandible : 9.8mm