Biomechanical consequences of shape variation in the modern human craniofacial skeleton

Additional Authors

Katerina Colwell, Department of Biomedical Health Sciences, East Tennessee State University, Johnson City, TN.

Abstract

The human cranium exhibits unique morphological traits among primates, including a small and gracile midface and retracted maxilla. Previous studies suggest that evolutionary reductions in human craniofacial size and robusticity have compromised its mechanical strength. However, the biomechanical consequences of morphological variation in the human craniofacial skeleton remain underexplored. This study investigates the relationship between craniofacial shape and strain magnitudes during masticatory loading, employing finite element analysis to simulate biomechanical performance across diverse morphologies. We used shape analysis to select six crania lying at the extremes of variation, as well as one “average” specimen close to the group centroid, from a regionally variable sample of recent humans. We analyzed finite element models of these crania during simulations of P3 biting. Models were assigned the same set of regionally variable bone material properties and the applied muscle forces were scaled based on differences in model volume. Data on von Mises microstrain magnitudes were collected along 6 linear transects that span all major facial regions on the biting side of the face. We found that most of the variation between models was surrounding the nasal root and along the nasal margin. Overall, our results suggest that having a prognathic face, particularly subnasally, combined with a vertically short and mediolaterally narrow face, results in the highest peaks in strain magnitude. However, prognathism does not always result in high strains. For example, another long-faced individual in the sample had some of the lowest strains, but most of this prognathism is midfacial and the face is very tall and wide. Our findings highlight the nuanced relationship between craniofacial morphology and mechanical performance, with implications extending beyond evolutionary biology to clinical applications. Understanding how specific patterns of facial shape influence strain magnitudes can inform the design and optimization of craniofacial surgical interventions, implants, and reconstructive therapies.

Start Time

16-4-2025 9:00 AM

End Time

16-4-2025 11:30 AM

Presentation Type

Poster

Presentation Category

Health

Student Type

Undergraduate Student

Faculty Mentor

Justin Ledogar

Faculty Department

Biomedical Health Sciences

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Apr 16th, 9:00 AM Apr 16th, 11:30 AM

Biomechanical consequences of shape variation in the modern human craniofacial skeleton

The human cranium exhibits unique morphological traits among primates, including a small and gracile midface and retracted maxilla. Previous studies suggest that evolutionary reductions in human craniofacial size and robusticity have compromised its mechanical strength. However, the biomechanical consequences of morphological variation in the human craniofacial skeleton remain underexplored. This study investigates the relationship between craniofacial shape and strain magnitudes during masticatory loading, employing finite element analysis to simulate biomechanical performance across diverse morphologies. We used shape analysis to select six crania lying at the extremes of variation, as well as one “average” specimen close to the group centroid, from a regionally variable sample of recent humans. We analyzed finite element models of these crania during simulations of P3 biting. Models were assigned the same set of regionally variable bone material properties and the applied muscle forces were scaled based on differences in model volume. Data on von Mises microstrain magnitudes were collected along 6 linear transects that span all major facial regions on the biting side of the face. We found that most of the variation between models was surrounding the nasal root and along the nasal margin. Overall, our results suggest that having a prognathic face, particularly subnasally, combined with a vertically short and mediolaterally narrow face, results in the highest peaks in strain magnitude. However, prognathism does not always result in high strains. For example, another long-faced individual in the sample had some of the lowest strains, but most of this prognathism is midfacial and the face is very tall and wide. Our findings highlight the nuanced relationship between craniofacial morphology and mechanical performance, with implications extending beyond evolutionary biology to clinical applications. Understanding how specific patterns of facial shape influence strain magnitudes can inform the design and optimization of craniofacial surgical interventions, implants, and reconstructive therapies.