Christopher W. Schmidt - University of Indianapolis Archeology ...

Position of the mental foramen. The position of the mental foramen is significantly
affected by ancestry. In the European sample, 54% have their mental foramina positioned
beneath the junction between the second and third premolar, whereas 46% of the African sample
has their mental foramina beneath the second premolar. Additionally, 20% of Africans have
their mental foramina placed even further back on the mandible, beneath the junction of the
second premolar and the first molar or beneath the first molar. Similarly, Zivanovic (1970)
found that 32% of his East African sample had the mental foramen beneath the junction of the
second premolar and the first molar. Therefore, it can be assumed that Europeans have a more
anteriorly placed mental foramen and Africans have a more posteriorly placed mental foramen.
Mandibular measurements. Ancestry significantly affects the measurements of
bigonial width, mandibular length, mandibular angle, and minimum ramus breadth. Europeans
tend to have a slightly larger bigonial width than Africans. However, the more extreme forms of
gonial eversion are more common in Africans. This discrepancy may be due to Africans having
stronger muscle attachments at the gonia and therefore creating more eversion, while Europeans
have generally wider mandibles, regardless of gonial eversion. Africans have a longer mandible,
smaller (more acute) gonial angle, and wider minimum ramus width in comparison to Europeans.
In contrast, Europeans have a shorter mandible, more obtuse gonial angle, and a thinner
mandibular ramus width than Africans. These measurements could be used to generate
discriminant functions that can distinguish between different ancestral groups.
Sexual Dimorphism in the Mandible
The skull is the second most sexually dimorphic region of the human skeleton, behind the
pelvis. As a component of the skull, the mandible may also be considered sexually dimorphic
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