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Basicranial influence on overall cranial shape
D E Lieberman1, O M Pearson, K M Mowbray
1Department of Anthropology, The George Washington University, 2110 G St, NW, Washington, DC 20052, USA. danlieb@gwu.edu
Journal of Human Evolution
|February 5, 2000
Summary
Cranial base breadth, not length or flexion, significantly impacts skull proportions by interacting with brain volume. This relationship influences facial shape and explains variations like occipital buns in humans and Neanderthals.
Area of Science:
- Human evolution
- Anthropometry
- Developmental biology
Background:
- Cranial base dimensions and brain volume are key factors in skull development.
- Understanding the interplay between these elements is crucial for explaining morphological variations.
Purpose of the Study:
- To investigate how cranial base dimensions (length, breadth, flexion) interact with brain volume.
- To model developmental interactions within the neuro-basicranial complex (NBC) and its influence on facial proportions.
- To test this model across diverse human populations.
Main Methods:
- Utilized exocranial and radiographic measurements from adult crania of five diverse populations.
- Applied statistical analysis to examine correlations between cranial base dimensions, brain volume, and skull proportions.
Main Results:
- Cranial base breadth (POB) significantly affects cranial proportions, primarily through its interaction with brain volume influencing NBC breadth.
- NBC width constrains facial width, impacting overall facial shape.
- Large brains on narrow cranial bases correlate with posterior occipital bone projection (occipital buns) in modern humans.
Conclusions:
- Cranial base breadth is a critical determinant of cranial and facial morphology, modulated by brain volume.
- Developmental integration between the cranial base and brain explains certain morphological variations, including occipital buns.
- Differences in cranial base width relative to brain volume may explain variations in occipital bun morphology between Homo sapiens and Neanderthals.
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