The mentalis muscle in relation to edentulous mandibles

Fifty mentalis muscles were examined on 25 adult human cadavers with edentulous mandibles. The following observations were made: 1. 1. The right and left mentalis muscles were symmetrically placed on either side of the midline of the edentulous mandible, and they were found to be apart by a mean distance of 12 mm. 2. 2. The mean width of the mentalis muscle at the origin was approximately 5 mm. 3. 3. The medial fibers of the mentalis muscle crossed the midline to join the mentalis muscle of the opposite side. The most superficial fibers of the mentalis muscle coursed upward to join the obicularis oris. 4. 4. Sixty-seven per cent (20 of 30) of the muscles examined originated on the crest of the bone of the residual ridge. Twenty-seven per cent (8 of 30) of the muscles examined originated between the crest of the bone of the residual ridge and the fornix of the labial vestibule. 5. 5. Twenty-one of 30 (70 per cent) mentalis muscles examined in Group B had origins which correlated with elevations on the mucous membrane surface as recorded in modeling compound.