Doctoral Dissertation Research: Form and function of the primate cervical spine

Arizona State University, Scottsdale AZ

Investigators

Abstract

The goal of this research is to understand the relationship between the shape of the neck bones (cervical vertebrae) and how they function in humans and our living relatives. The co-PI will address this question by comparing the shape of the bones to both the movement of the spine during walking and its maximum ranges of motion in living lemurs and apes. The relationships between spinal form and function established in this study have implications for both anthropological and medical fields. Spine research often uses non-human primates as models for spinal injury and treatment without understanding the functional differences that may exist between humans and their living relatives. This research will have implications for the appropriateness of non-human primates in spinal medical research. In addition, this lab-based study is a first step towards conducting field research. As primate habitats become increasingly fragmented due to human influence, the ways in which primate change their locomotor habits to accommodate this fragmentation has implications for their survival. This research will also act as the cornerstone of the co-PI's career as a female scientist. As such, it will provide the opportunity for her to mentor undergraduate students and offers research training that is vital for her future career. The neck is an understudied, yet significant, anatomical region. It is especially important in primates because it maintains postural stability during the diverse forms of locomotion practice by the primate order. Stability is especially important in the head because it houses the eyes and inner ears, which allow animals to efficiently navigate complex environments. Within our hominin lineage, drastic changes have occurred in both the shape and size of the head as well as our manner of walking. These changes likely affected how the neck balanced the head in our fossil ancestors. The relationship between neck form and neck function will be addressed by collecting two measures of form: radiographs of maximum ranges of head and neck motion and range of head and neck motion during locomotion. These measures of form will be statistically compared to specific measures of vertebral form taken from 3D scans of skeletal specimens. The statistical relationships will then be used to understand the function of fossil species based on the preserved form. This work will further the understanding of neck function, its relationships to vertebral form, and its evolution within the hominin lineage.