The dentate adult human mandible: an anatomic basis for surgical decision making.

Mandibular resection for oral cancer assumes two major forms; segmental mandibulectomy for invasion and rim mandibulectomy for margins, the extent of removal being governed by the need to ensure oncologic safety. The purpose of our study was to establish basic principles for optimal resection design in various clinical situations. Thirty-six cadaveric, adult, dentate human mandibles were examined in detail and sectioned at six points each to study the cross- sectional anatomy at these sites. The majority of bones (32 of 36) revealed a conspicuous medullary core with a thin cortical rim 2 to 4 mm in thickness. The inferior alveolar nerve was found to course consistently within the anterior segment of the ramus and to dip significantly within the body (median height at molar area 7 mm). Accordingly, rim resections cannot include the entire medullary core and nerve as currently defined, whereas segmental resections can spare the posterior segment of the ramus in appropriate cases.