The Polynesian head: growth and form

Area of Science:

• Anthropology
• Craniofacial development
• Biomechanics

Background:

• The cranial base is a key factor in determining craniofacial morphology.
• Polynesian populations exhibit distinct head and mandibular forms.
• Cranial base shape influences facial skeletal development and occlusion.

Purpose of the Study:

• To investigate the cranial base as the primary determinant of head and mandibular form in adult Polynesians.
• To elucidate the developmental adaptations of the facial skeleton and mandible to cranial base morphology.
• To understand the functional consequences of these adaptations on masticatory musculature and facial structure.

Main Methods:

• Analysis of craniofacial morphology in adult Polynesians.
• Developmental trajectory analysis of the upper facial skeleton and mandible.
• Assessment of the relationship between cranial base flatness and facial prognathism.
• Evaluation of compensatory masticatory muscle development.

Main Results:

• A flat cranial base is identified as the primordial determinant of Polynesian head and mandibular shape.
• Significant adjustments in the upper facial skeleton and maxillary occlusal plane occur during development to accommodate the cranial base.
• The mandible undergoes extreme shape and positional changes to maintain occlusion.
• Adaptations result in a vertically disposed, orthognathic bony profile, a large nasopharynx, and enhanced masticatory musculature.

Conclusions:

• The cranial base plays a critical role in shaping the craniofacial complex, particularly in Polynesian populations.
• Developmental plasticity allows the facial skeleton and mandible to adapt to the constraints of the cranial base.
• These adaptations have significant functional implications for mastication and overall facial morphology.