Temporal crest canal: case report and statistics on a rare mandibular variant.

A child's mandible retrieved from a North American archaeological site had an anomalous canal 2 mm in diameter and 10 mm long, opening posteriorly behind the temporal crest and anteriorly in the retromolar fossa. Radiographic analysis revealed a second canal passing down from the temporal crest canal (TCC) toward the molar roots. A survey of retromolar variants in a large skeletal series (N2391) revealed TCC present in 1.7% of all persons on average, ranging up to 23% in certain population samples. It appeared to be more common in males than in females and in native Americans than in other racial groups. From its location and orientation, TCC was inferred to have conveyed all or part of the buccal nerve. The clinical significance of this variant is that pain fibers from the molar roots joining the nerve as it runs in this canal would exit the bone behind the temporal crest, thus escaping anesthetization in routine injections for inferior alveolar and buccal nerve block.