The Related Anatomical Research On The Block Anesthesia Of Inferior Alveolar Nerve

ObjectiveTo make the applied anatomy research on the mandibular bone and the inferior alveolar nerve and adjacent blood vessels and nerves, so as to provide complete anatomical data and evidence for lowering complication and elevating anesthesia effect during inferior alveolar nerve block.Material and Method1. The following details of adult mandibular bone samples in 50 examples(100 sides) were mearsured by sliding caliper and conimeter: the minimum distance from the mandibular foramen core to the anterior border of ramus; to the posteromarginal border of ramus; to the mandibular notch; to inferior margin of mandibular body; the height of the mandibular body; the thickness of the mandibular body; the height of the mandibular ramus; the minimum breadth of the mandibular ramus; the madibular angle; the breadth within the madibular angle, and so on. Moreover, the following were observed which included the localization relation between mandibular lingual and mandibular foramen and the type of mandibular foramen.2. 30 adults half head cadavers were selected. Firstly, turned the face up, and made the traverse notch along below of the body of the mandible, and made the arc notch from the madibular angle and the anterior border of acoustic duct to the start point of temporalis, and made the traverse notch along the superior of zygomatic arch. Secondly, cut off the muscle of facial expression and the masseter in this region, saw the zugomatic arth and exposed the mandibular ramus and tendon of temporalis. Then, to remove the coronoid process with rongeur, get rid of the fatty tissue within pterygomandibular space.Finally, to expose and observe the inferior alveolar nerve, lingual nerve, buccal nerve, mylohyoid nerve, branch of inferior maxillary nerve and arteria maxillaris, then to measure the breadth and the thickness of the trunk of nerve above-mentioned, the diameter of the maxillary artery, the distance beween the beginning of the maxillary artery and middle meningeal artery.3. To observe the position of pterygomandibular space, and to measure the length, breadth and height of the plane of pterygomandibular space higher 1.00cm than mandibular foramen. The length was defined as the distance between posterior margintendon of the tender of musculus temporalis and posterior margin of mandible ramus; the breadth as the distance between medial surface of mandible ramus and internal pterygoid muscle; the height as the distance between inferior of the external pterygoid muscle border and lower margin of internal pterygoid muscle.4. Firstly, to turn down the side face of a cadaver without being anatomized, and one assistant let the mouth open to expose the plica pterygomandibulare and pointed of buccal pad;. The pointed of buccal pad was marked so as to complete the measurement when the cadaver was rebuilt. Secondly, to cut the mucosa to be 6cm a little bit out of the fines- submaxilla plica, extended to facies distalis dentis of the second molarsw. Then to separate the notch with pincers, and cut through membrana mucosa, submucous tissue up to anterior border of ramus, continue to separate along the space between facies medialis of mandible ramus and internal pterygoid muscle. And to find the mandibular foramen and inferior alveolar neurovascular bundle at the backside of the lingula mandibulae. Finally, to rebuild the cadaver, then to imitate the way of the inferior alveolar nerve block with in-mouth and out-mouth injection on the median sagittal plane example using the anesthetic needle(4 model of long ) and to measure the depth and angle.Resluts1. The mandibular lingual has three styles in the medial surface of mandible ramus: being head of mandibular foramen is 55%(55sides);being forent and medial surface is 37%(37sides);being medial surface is 8%(8sides). The type of mandibular foramen is triangle(85%) and ellipse(15%).2. The minimum distance from the mandibular foramen core to the anterior border of ramus , to the posteromarginal border of ramus , to the mandibular notch and to the inferor margin of mandibular body are respectively 17.87±2.18 mm, 15.83±2.23 mm, 23.24±2.81 mm and 25.76±3.66 mm.3. The breadth and length of the plane of pterygomandibular space higher 1.00cm than mandibular foramen are respectively 13.60±2.70 mm and 22.20±4.10 mm, the height is 28.50±4.70 mm. The breadth of the mandibular nerve, inferior alveolar nerve, lingual nerve, buccal nerve are respectively 4.90±1.30 mm, 2.60±0.50 mm, 2.40±0.60 mm, 1.60±0.40 mm.4. The best angle of the inferior alveolar nerve block through mouth beween injection needles and linea mediana is 43.2±2.3°, and the best depth is 22.20±3.20 mm. The best angle of the inferior alveolar nerve block through gonion along indide of the mandible ramus outside mouth beween injection needles and posteromarginal border of ramus is 34.1±1.3°, and the cest depth is 33.10±2.90 mm.Conclusion1. The mandibular foramen is located on the pone-anodic of inside mandible ramus.2. lingula mandibulae must be avoided to inject during the block anesthesia of inferior alveolar nerve to take good effect.3. The anaesthetic must be injected to the middle and upper of the pterygomandi- bular space during the inferior alveolar nerve block, since the pterygomandibular space is narrow, and the upper is broader than the rear.4. The madibular angle point is used to be the outside mouth injection point during the inferior alveolar nerve block. This point is fixed and easy to be found, and the operation is easily to be taken. Moreover, the complication of operation seldom appears through this operation method and the anesthesia is much more successful. During the inferior alveolar nerve block, the best injection angle and depth should be mastered so as to get the best anaesthesia effect.