下颌神经管的解剖结构

背景:在下颌后牙种植术中,由于下颌神经管走行于下颌骨体内,有时可损伤下齿槽神经,因而制约了牙种植术的应用。 因此,牙种植术的应用需详细了解下颌神经管的解剖结构。 目的：观察下颌神经管在下颌骨内的走行及管内的解剖结构。 方法：共纳入15具成人牙下颌骨标本与4具新鲜下颌骨动脉灌注标本。纳入对象均牙列完整,后牙无缺失,牙槽骨无吸收。测量15具成人牙下颌骨标本下颌管走行及其管腔各径长度,包括下颌管横径与纵径,下颌管至上下内外缘距离。观察4具新鲜下颌骨动脉灌注标本管内下颌神经管内神经、血管位置关系。 结果与结论：下颌管内缘至舌侧骨板的距离比下颌管外缘至颊侧骨板距离短(P < 0.01);下颌管上缘至牙槽嵴顶的距离较下颌管下缘至下颌骨下缘的距离大(P < 0.01)。表明下颌管在下颌骨体部走行中偏舌侧、偏下颌骨下缘。下颌神经管在下颌骨体部的部分横径小于纵径(P < 0.05),亦即下颌管截面形态为上下径略长的椭圆形。神经管横纵径于前后牙位区差异无显著性意义。实验还发现在暴露的下颌管腔中下牙槽神经及伴随血管有一层被膜包绕成神经血管束,血管位于神经上方,而且位置恒定,并发出小分支包绕神经。结果提示,下牙槽血管神经束在下颌管内走行中血管位于神经之上。

Anatomic structure of the mandibular canal

BACKGROUND:In mandibular posterior dental implantation, injury to the inferior alveolar nerve sometimes occurs because of mandibular canal going across mandibular body. This restricts the use of dental implantation at this site. Therefore, it is essential to understand the anatomic structure of inferior alveolar nerve canal in mandibular posterior dental implantation. OBJECTIVE: To observe the intramandibular course of and anatomic structure of inferior alveolar nerve canal. METHODS:Fifteen adult complete mandible specimens with teeth and 4 fresh mandible arterial infusion specimens were researched. All the specimens had complete dentition and there were no obvious absorption in alveolar bone. The course of inferior alveolar nerve canal and its dimension including transverse and longitudinal diameters of mandibular canal and the distance between mandibular canal and mandible each side (superior, inferior, buccal and lingual side) were measured in 15 adult mandibles with teeth. The relationship between blood vessels and nerve of the canal was observed in 4 fresh arterial infusion specimens. RESULTS AND CONCLUSION:The distance between the medial border of the mandibular canal and the lingual wall was shorter than that of the lateral wall of the mandibular canal to the buccal wall (P < 0.01); The length from the upper wall of mandibiular canal to the top of the alveolar ridge was longer than that of the inferior border of the mandibular canal to the inferior border of the mandible (P < 0.01). The longitudinal diameter was smaller than the transverse diameter (P < 0.05), namely, the cross section of the mandibular canal was an ellipse with a longer longitudinal diameter. There was no significant difference between the transverse and longitudinal diameters of the canal in the anterior and posterior teeth region of the mandible. The inferior alveolar nerve and its associated blood vessels were located within a nervous vascular bunch in the mandibular canals. In every fresh specimen the blood vessels lay above the nerve. There were small branches of blood vessels surrounding the nerve. The mandibular canal ran towards the lingual side and was close to the inferior margin of the mandible.