下颌神经管全长三维走向的测量及其临床意义

目的　研究下颌管的全长走行位置及其与四周骨板的毗邻关系 ,为临床下颌手术提供解剖学依据。方法　对14 0侧成人下颌骨进行冠状、矢状及水平三维剖面的测量。找出下牙槽神经管全长在下颌骨中走行的基本位置及其与四周骨松质、骨皮质的毗邻关系值。结果　下牙槽神经管在下颌骨中走行虽有变化 ,但下颌管全长的总体走行是紧贴着舌侧骨板 ;在下颌第一、二磨牙区下颌管走行与下颌下缘成平行状 ;在近颏孔时才折转向外和向颊侧出颏孔。结论　在牙种植术、下颌各类截骨术中按正常解剖方位并侧重于颊侧骨板操作 ,可以避免损伤下牙槽神经血管。     

下颌管的应用解剖及临床意义

目的:为下颌牙种植术等临床口腔外科提供解剖学基础.方法:选取下颌骨标本10例、新鲜下颌骨标本10例和成人全牙下颌骨标本20例,分别暴露出下颌管截面、下牙槽神经血管束和下颌管与下颌后牙牙根.观察下颌管的形态、走行和下牙槽神经、血管的排列关系,用游标卡尺测量下颌后牙牙根尖至下颌管上壁的距离.结果:下颌管呈椭圆形,自磨牙牙根尖舌侧和前磨牙牙根尖颊侧的下方走行;下颌管内的下牙槽血管位于下牙槽神经上方.下颌后牙牙根至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙;下颌磨牙的远中根至下颌管的距离均较近中根近.第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的最短距离分别为(8.19±0.87) mm(左)和(8.29±0.88) mm(右)、(7.38±0.85) mm、(3.30±0.66) mm、(2.98±0.77) mm(左)和(2.92±0.75) mm(右)、(3.82±0.63) mm(左)和(3.86±0.64) mm(右).结论:下颌管的应用解剖对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义.     

下颌管与下颌后牙的位置关系及临床意义

目的: 为下颌牙种植术等临床口腔外科提供解剖学基础。方法：选取新鲜下颌骨标本10例、成人全牙下颌骨标本18例和20名全牙志愿者,分别暴露出下牙槽神经血管束、下颌管与下颌后牙牙根和CT连续扫描后进行三维重建。观察下牙槽神经、血管的排列关系,用游标卡尺和CT三维重建工作站分别测量下颌后牙牙根至下颌管上壁的距离。结果：下颌管自牙槽窝下方走行,其舌侧骨板较厚;下颌管内的下牙槽血管位于下牙槽神经上方。下颌磨牙的远中根至下颌管的距离均较近中根近。在标本及影像上的第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的距离分别为(8.36±2.34)　mm和(8.42±2.42)mm、(7.36±2.21)mm和(7.52±2.18)mm、(3.22±1.40)mm和(3.36±1.85)mm、(2.96±1.54)mm和(2.84±1.55)mm、(3.64±1.72)mm和(3.88±1.76)mm。结论：（1）下颌后牙至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙。（2）对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义。     

颏管的形态特点及其临床意义

目的研究国人颏管的形态与位置,为口腔科牙种植术等颏区手术提供解剖学数据.方法剖开60侧福尔马林固定的湿下颌骨标本的下颌管前端,进行观察测量.结果下颌管前端向中线分出一切牙神经管后,该管有96.7%弯向后上形成颏管再开口于颏孔,3.3%直接开口于颏孔;颏管长约(4.01±1.20)mm,管径约(2.6±0.6)mm;颏孔前缘对应下颌管前端的水平距离为(3.54±0.70)mm,颏孔下缘至下颌管上缘的垂直距离为(3.21±0.90)mm;下牙槽神经在下颌管末端分成两支;切牙神经穿切牙神经管分布到切牙,颏神经穿颏管出颏孔.结论下颌管前端向后上方续为颏管,颏管内有颏神经走行.     

下颌管的三维重建及临床意义

目的　为下颌牙种植术等临床口腔外科提供解剖学基础。 方法　选取全牙志愿者20名,在螺旋CT机以眶耳线(OML)为基线连续扫描,采用ADW 4.2重建软件的曲面重组技术(CPR)重建下颌管,观察下颌管的位置、构造和测量下颌后牙牙根至下颌管上壁的距离;在Amira三维重建软件下重建下颌骨及下颌管的可视化模型,观察透明下颌骨内下颌管的走行及其与下颌后牙的关系。 结果　下颌管壁由一薄层骨密质构成,自磨牙牙根尖舌侧和前磨牙牙根尖颊侧的下方走行;透明下颌骨内的下颌管可清晰显示其位置、形态及走行,下颌管与下颌体下缘、牙槽嵴及内、外侧骨板的距离。下颌后牙牙根至下颌管的距离以第2磨牙最近,由近及远依次为第2磨牙、第1磨牙、第3磨牙、第2前磨牙和第1前磨牙;下颌磨牙的远中根至下颌管的距离均较近中根近。第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的最短距离分别为(8.38±1.04) mm(左)和(8.44±1.05) mm(右)、(7.51±0.85) mm、(3.40±　0.65) mm、(2.93±0.61) mm、(3.92±0.63) mm(左)和(3.97±0.63) mm(右)。 结论　下颌管的三维重建对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经等具有重要意义。     

下颌角肥大整形术相关解剖

目的 精细解剖下颌角周围软组织结构及下颌神经管,为下颌角肥大整形术提供解剖学参考。 方法 20例大体标本,观察及测量面动静脉、面神经下颌缘支及咬肌区的血管和神经。据下颌骨表面骨性标志定位5条径线,测量该5条径线上下颌神经管在下颌骨中的位置。计算各软组织结构和下颌神经管的安全范围。 结果 面动脉距下颌角点为23.18～36.28 mm,距咬肌前缘为-9.51～9.27 mm。面静脉距离下颌角点为17.79～32.03 mm。面神经下颌缘支贴近下颌角部及下颌骨下缘走行,距离下颌角点为-8.57～10.70 mm,而咬肌前缘下颌缘支距下颌骨下缘为-8.83～11.06 mm。咬肌的血供主要有面动脉咬肌支、颈外动脉咬肌支、上颌动脉咬肌支及面横动脉咬肌支这四大来源。咬肌神经多与咬肌动脉伴行进入咬肌。下颌神经管在5个截面中距离下颌骨外侧点分别大于10.50 mm、14.72 mm、15.60 mm、8.53 mm、6.74 mm。 结论 在剥离下颌角区软组织时,注意对咬肌前缘面动脉、面神经下颌缘支及下颌角点附近面神经下颌缘支的保护。去除咬肌的最佳层次为咬肌深层中份最厚点及中下份。而在截骨或劈骨时,根据下颌神经管的安全范围,可在下颌骨颊侧骨板快速画出一条指导性的安全线。     

螺旋CT三维成像及曲面断层片对下颌神经管走向的研究

目的　通过螺旋CT及曲面断层片探讨下颌神经管与下颌骨的实际位置关系。 方法　利用螺旋CT扫描机对正常年青人进行下颌骨的横断面连续薄层扫描及多平面重建后,测量并计算下颌神经管在下颌骨中的实际位置及其走行方向。对上述人群拍摄曲面断层片,在曲面断层片上测量并计算下颌神经管在下颌骨中的位置并将两种测量结果进行比较。 结果　在颊舌方向,下颌神经管总体走行是由舌侧逐渐向颊侧倾斜达颏孔,在走行高度上,在第三磨牙区由上向下走行,自第二磨牙开始下颌神经管逐渐由下向上走行达颏孔。下颌神经管在下颌骨中位置的测量并计算的比值,在两种检测方法中无显著性差异（P＜0.05）。 结论　本研究螺旋CT测量并计算出的比值校正曲面断层片测量并计算的结果,可以在临床工作中指导牙槽外科手术。     

舌神经的解剖观测及其临床意义

在33侧成人头颈部标本和61块下颌骨标本上对舌神经在下颌第三磨牙舌侧区的位置及其与周围结构的毗邻关系进行了观测。舌神经在第三磨牙舌侧正中垂线上至牙龈的距离为11.7mm,至舌侧骨板的水平距离为3.1mm。第三磨牙根尖至内侧牙槽嵴的距离为11.3mm。依据观测结果,结合下颌第三磨牙拨除术等讨论了有关应用解剖学要点.     

磨牙与下颌管、上颌窦的位置关系及临床意义

目的:为牙种植术等临床口腔外科提供解剖学基础.方法:选取新鲜及成人全牙上、下颌骨标本和全牙志愿者,观察下牙槽神经、血管的关系和上颌窦下壁的凸起结构,测量磨牙牙根至下颌管、上颌窦的距离和牙槽窝的深度.结果:下颌管内的下牙槽血管位于下牙槽神经上方,下颌第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的距离分别为(3.22±1.40)mm、(2.96±1.54)mm、(3.64±1.72)mm.上颌窦下壁有凸起的骨隔和黏膜隔,上颌第1磨牙、第2磨牙、第3磨牙牙根至上颌窦下壁的距离分别为(2.02±0.91)mm、(2.06±1.04)mm、(3.74±1.73)mm.下颌磨牙的牙槽窝深度均大于上颌磨牙相应的牙槽窝.结论:磨牙牙根至下颌管、上颌窦的距离和牙槽窝的深度对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经和误入上颌窦等具有重要意义.     

下颌管位置与下颌支矢状劈开术的关系

在50侧成人下颌骨的切面上,观察测量了下颌管在下颌支矢状截骨术的位置,下颌管至下颌骨内、外侧面,上、下缘的距离等。从解剖学角度讨论了术中防止下齿槽神经损伤的要点。     

Transverse cervical nerve: Implications for dental anesthesia

The inferior alveolar nerve block (IANB) has the highest failure incidence of any dental anesthetic technique. Many authors have outlined potential reasons for these failures in permanent lower molars, including accessory innervations from the mylohyoid and mental foramen. However, the potential accessory innervation of posterior mandibular teeth from the transverse cervical nerve (TCN), a branch of ventral rami from the C2–C3 spinal nerves from the cervical plexus (CP), has been difficult to assess as a result of the small size and thickness of the mandibular accessory foramina and nerve branches, as well as due to the dissection technique performed. The goal of this study was to identify and trace the CP branches from fresh human cadaver tissue samples using the Sihler's technique. Two fresh human cadaver samples were used. Samples were fixed in neutralized formalin, macerated in potassium hydroxide, decalcified in acetic acid, stained in Ehrlich's hematoxylin, destained in acetic acid, and cleared in glycerin. Both specimens skin was dissected. The Sihler's technique delineated all nerves three dimensionally and helped to disclose structures of small size and thickness. The TCN from the CP, stained in blue, innervated the posterior mandible in one of the two samples. These results confirmed that the CP may supply accessory innervation to the inferior border of the posterior mandible through the TCN. These findings illustrate variations of anatomy that may account for IANB failures in posterior mandibular teeth and allows for clinical decisions for implementing supplemental anesthetic techniques. Clin. Anat. 26:688–692, 2013. © 2013 Wiley Periodicals, Inc.     

Rare courses of the mandibular canal in the molar regions of the human mandible: a cadaveric study

The inferior alveolar artery, vein and nerve send some branches to the molar teeth via the mandibular canal to the mental foramen. The present study attempted to define the presence and course of the mandibular canal in the mandible with the alveolar process by macroscopic cadaveric dissection and computerized tomography (CT) in order to provide information that might prevent injuries to vessels and nerves at risk during root canal treatment. We identified the position of the mandibular canal within a 30% ratio of the distance from inferior border of mandible to the apices of the root for 39 out of 131 sides (mesial root of first molar, 20%; distal root of first molar, 22.6%; mesial root of second molar, 27.8% and distal root of second molar, 47%) on panoramic X-ray observation. In one cadaver (male, 64 years old), the root apex of the second molar was in close proximity to the upper bony mandibular canal. Macroscopic dissection and computerized tomography showed that the main trunks of the inferior alveolar artery, vein, and nerve were in tight contact with the apex of the second molar. These observations of the anatomic course of the mandibular canal will be important to consider during root canal treatment of mandibular teeth.     

上、下颌骨的CT影像与断层标本对照研究及临床意义

目的:为牙种植术等临床口腔外科提供解剖学基础.方法:选取成人全牙上、下颌骨标本和志愿者全牙CT重建影像各20例,观察上颌窦下壁的凸起结构和下颌管的走行,测量上颌窦下壁、下颌管上壁至牙根的距离.结果:上颌窦系呈三边形或四边形的锥形腔隙,其下壁常有凸起的骨隔.在标本及影像上的上颌窦下壁至第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根的距离左、右分别为(9.30±2.64)mm和(9.50±2.72)mm、(4.50±1.98)mm和(4.60±1.95)mm、(2.02±0.91) mm和(2.18±0.96)mm、(2.06±1.04) mm和(2.26±1.20)mm、(3.74±1.73)mm和(3.82±1.84)mm.下颌管自牙槽窝下方走行,其舌侧骨板较厚.在标本及影像上的下颌管上壁至第1前磨牙、第2前磨牙、第1磨牙、第2磨牙、第3磨牙牙根的距离左、右分别为(8.36 +2.34) mm和(8.42±2.42)mm、(7.36±2.21)mm和(7.52±2.18)mm、(3.22±1.40)mm和(3.36±1.85)mm、(2.96±1.54)mm和(2.84±1.55)mm、(3.64±1.72) mm和(3.88±1.76)mm.结论:上颌窦、下颌管至牙根的距离测量,对选择适宜长度的牙种植体,避免牙种植体误入上颌窦和损伤下牙槽神经等具有重要意义.     

The mandibular canal of the edentulous jaw.

The morphology of the mandibular canal after loss of teeth has received little detailed attention. Improved documentation of this topic would allow better interpretation of dental radiographs and would enable those engaged in tooth implantation to better understand the nature of the tissue into which the prostheses are placed. In this study on mandibles from seven dissecting room cadavers panoramic radiographs usually showed the mandibular canal clearly, an incisive canal less so. The wall of the mandibular canal was similar in dentate and edentulous mandibles, and was highly perforated, as suggested by Cryer (Anderson et al., 1991). In edentulous specimens, it was composed mainly of cancellous bone with only occasional single osteons. The inferior alveolar nerve near the mandibular foramen was a large trunk, consisting of three to four nerve bundles with connective tissue sheaths. It became more loosely arranged toward the mental foramen. Medial to the mental foramen, the nerves were frequently in the form of small bundles in the marrow. Any incisive canal was ill-defined and neurovascular bundles, when present, ran through a labyrinth of intertrabecular spaces.     

The position of the mandibular canal and histologic feature of the inferior alveolar nerve

The inferior alveolar nerve is the one of the large branches of the mandibular division of the trigeminal nerve. It is vulnerable during surgical procedures of the mandible. Despite its importance, no anatomical and histological examination has been conducted to provide a detailed cross‐sectional morphology of the mandibular canal according to dental status. Therefore, the present study aimed to identify the position of the mandibular canal through direct measurement and to determine the branches of the inferior alveolar nerve through histologic examination. The area between the anterior margin of the third molar and the anterior margin of the second premolar of dentulous, partially dentulous, and edentulous hemimandible specimens (n = 49) from 26 human cadavers was serially sectioned into seven segments, and specific distances were measured using digital calipers. Following this, 5‐μm cross‐sections were prepared along the mandibular canal and mental foramen, and examined by fluorescence microscopy. The mandibular canal was located at a mean distance of 10.52 mm above the inferior margin of the mandible. The mean maximum diameters of the mandibular canal, inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein were 2.52, 1.84, 0.42, and 0.58 mm, respectively. This study found that the inferior alveolar nerve often gives rise to several branches at each level (range 0–3). To minimize the risk of injury, knowledge of the small branches of the nerve and of the detailed findings regarding the position of the mandibular canal reported here should be considered when planning mandibular surgery, especially during implant placement. Clin. Anat. 23:34–42, 2010. © 2009 Wiley‐Liss, Inc.     

Nervous control of blood flow in the dental pulp in dogs

Pulpal blood flow (PBF) was measured by H₂-gas clearance in 30 dogs during electrical nerve stimulation, denervation and close intraarterial infusion of noradrenaline (NA). Electrical stimulation of the cervical sympathetic nerve and NA infusion always resulted in decreased PBF. The constrictor effect was reduced by α-blockers, but was never abolished or reversed to a vasodilation. Thus, no evidence for β-receptors in the dental pulp blood vessels was found. The fall in PBF produced by cervical sympathetic stimulation could be prevented by cutting the inferior alveolar nerve in the mandibular canal. Stimulation of the cut inferior alveolar nerve in the mandibular canal produced variable pulpal flow changes: Both a marked increase and decrease were measured. The flow changes during inferior nerve stimulation were unaffected by α-receptor blockade, while atropine reduced the vasoconstrictor respons or augmented the dilatory response. Electrical stimulation of the mandibular nerve before its entrance in the canal caused vasodilation, proposing a sensory antidromic axonreflex in the dental pulp. Sympathetic denervation had little or no effect on PBF, while cutting of the inferior alveolar nerve in the canal increased PBF in lower canine from 0.159 to 0.219 ml/min. g. The experiments show that pulp blood vessels of the dog may be controlled by both vasodilator and vasoconstrictor nerve fibers.     

Blood supply of the human fetal mandible

Gross anatomic and radiologic studies of the blood supply to the human mandible of the full-term fetus and newborn infant were performed on 22 specimens ranging from 320–538 mm crown-heel length and 1,192–4,108 gm in weight. Ten specimens were injected with red-lead and liquid soap to demonstrate the arteries radiographically. Twelve other specimens were injected with Castolite with a sprinkling of red-lead and yellow dye. The best side of each specimen was studied by radiography and dissection. This study demonstrated: (1) a masseteric arterial plexus supplying the coronoid process and the lateral wall of the ramus with contributions from the facial, masseter, transverse facial and external carotid arteries or combinations thereof; (2) a mental arterial plexus anastomosing with the mental, submental and inferior labial arteries; (3) an inferior alveolar artery supplying most of the body of the mandible with a majority of its branches passing in an upward direction; and (4) periosteal vessels supplying the lower border of the mandible and receiving their blood supply from the blood vessels supplying the muscles attaching to these areas and the periosteum. Supplemental to the above findings were anastomoses between the submental, mylohyoid and sublingual arteries along the medial border of the mandible. Also a significant variation not previously recorded was noted in one specimen in which the sublingual artery originated from the facial artery rather than the lingual.