Position and course of the mandibular canal in skulls
ABSTRACT The aim of this study was to examine and describe the topography of the mandibular canal (MC) in both vertical and occlusal dimensions.
Fifty-two adult skulls deposited in the University of Pittsburgh School of Dental Medicine skull collection were evaluated in this study. Cone-beam computerized tomographic scans of each skull were obtained.
The vertical course of MC was classified into 3 types: straight projection (12.2%), catenary-like configuration (51.1%), and progressive descent from posterior to anterior (36.7%). The evaluation of the buccolingual dimension showed that the mandibular canal was located either in contact with or close to the lingual cortical plate (≤2 mm) in the molar region of the majority of the cases. As it proceeds anteriorly it moves toward the buccal aspect of the mandible, where it finally emerges through the mental foramen. Three emerging patterns of mandibular canal were observed: sharp turn (53.2%), soft curved exit (28.8%), and straight path (17.4%). The examination of the vertical dimension showed that the canal was located almost 1 cm above the inferior border of the mandible and then ascended to reach the mental foramen, which is located ∼16 mm (range 13.4-20.3 mm) above the inferior border of the mandible. We found a strong correlation between height of the mandible and location of the mental foramen (r = 0.64; P < .0001).
The course of mandibular canal described in vertical and axial dimensions and variation in its path have been classified. In addition to variation in location of MC, it has different anatomic configurations which clinicians should be familiar with in any surgical procedures involving the posterior mandible.
SourceAvailable from: PubMed Central[Show abstract] [Hide abstract]
ABSTRACT: This study was performed to investigate the course of the mandibular canal on panoramic radiography and the visibility of this canal on both panoramic radiography and cone-beam computed tomography (CBCT). The study consisted of panoramic radiographs and CBCT images from 262 patients. The course of the mandibular canal, as seen in panoramic radiographs, was classified into four types: linear, elliptical, spoon-shaped, and turning curves. The visibility of this canal from the first to the third molar region was evaluated by visually determining whether the mandibular canal was clearly visible, probably visible, or invisible. The visibihlity of the canal on panoramic radiographs was compared with that on CBCT images. Elliptical curves were most frequently observed along the course of the mandibular canal. The percentage of clearly visible mandibular canals was the highest among the spoon-shaped curves and the lowest among the linear curves. On panoramic radiographs, invisible mandibular canals were found in 22.7% of the examined sites in the first molar region, 11.8% in the second molar region, and 1.3% in the third molar region. On CBCT cross-sectional images, the mandibular canal was invisible in 8.2% of the examined sites in the first molar region, 5.7% in the second molar region, and 0.2% in the third molar region. The visibility of this canal was lower in the first molar region than in the third molar region. The mandibular canal presented better visibility on CBCT images than on panoramic radiographs.12/2014; 44(4):273-278. DOI:10.5624/isd.2014.44.4.273
[Show abstract] [Hide abstract]
ABSTRACT: Some anatomic patterns formed by the anterior border of the ascending ramus relative to the mandibular canal can cause nerve complications during surgery. We determined the frequency of obstructive anatomy in patients undergoing jaw surgery, and we described a perioperative method for a bilateral sagittal split osteotomy that ensured inferior alveolar nerve (IAN) protection. The anatomy of the anterior border of the ascending ramus of the mandible was examined on axial and cross-sectional cone beam computed tomographic images of 114 consecutive patients undergoing bilateral sagittal split osteotomies. The thickness of the anterior border of the ascending ramus determined whether the mandibular foramen could be visualized (pattern A) or was obscured (pattern B). Patients with pattern B anatomy received a perioperative procedure.Direct visualization of the mandibular foramen was achieved in 100% of patients with pattern A anatomy. We examined 228 anterior borders of the ascending ramus of the mandible relative to the mandibular foramen in 114 patients. Pattern A was observed in 146 cases (64%); pattern B, in 82 (36%) cases. The use of the nerve hook resulted in no injuries to the IAN in all cases.The described procedure ensured direct visualization of the IAN, which prevented inadvertent damage to the IAN during instrumentation and surgical procedures at the mandibular foramen.Journal of Craniofacial Surgery 06/2014; DOI:10.1097/SCS.0000000000000849 · 0.68 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: The aim was to correlate the level of the inferior alveolar canal on cadaver specimens and as evaluated with three-dimensional radiographic cone-beam computed tomography (CBCT) imaging. Twenty-one skulls with intact mandibles (42 inferior alveolar canals) were imaged with an I-CAT Cone-Beam 3D Imaging System and multi-planar reformatted images obtained were scored to assess the level of the canal (Level I, Level II, and Level III). The mandibles were later dissected and level of the canal was directly visualized, scored, and further correlated with results from CBCT imaging. There was no difference in the level of the inferior alveolar canal between the dissected cadaver specimen and CBCT images. Also, there was no statistically significant difference in the level of the canal among the gender assigned to the specimens and corresponding CBCT images. There were no statistical differences in the level of the canal (cadaver specimen vs. CBCT) between the left and right sides of the specimens, as studied individually. Our study indicates that there is close correlation of the level of the inferior alveolar canal between cadaver specimens and CBCT images. Well-designed studies would be required to further validate the findings in this study.Surgical and Radiologic Anatomy 12/2014; DOI:10.1007/s00276-014-1385-4 · 1.33 Impact Factor