Bachelor of Science (BS), Ohio University, 2023, Biological Sciences

Properties of the avian skeleton system such as histological organization and cross-sectional geometry have been used to make inferences about organismal biology, locomotion, ecology, and evolution. However, we lack a fundamental organization about how bone naturally develops. This study is the first of its kind, examining developments in vascular orientation, shape, and post-cranial pneumatization in a controlled turkey model. The use of such a model allows for the observation of natural bone development in the absence of ecological or locomotive factors. The humerus and ulna were examined using both micro-CT and a histological workflow. Our results indicate certain periods (weeks 5-7) characterized by notable increase in length and cross-sectional shape measured used to infer resistance to mechanical loading. There is also variation in cortical area (thickness) that may be due to redistribution of cortical bone around the neutral axis. Circumferential canals appear at the border of developing bone and later in the growth series, suggesting it is a normal part of bone development. However, regional differences in histological organization paint a complicated picture between canal orientation and factors such as growth or locomotion. Post-cranial pneumatization of the midshaft appears at week 4 in humeri and air-like space is found in the ulna, which has previously been interpreted as a non-pneumatic bone. This project lays a foundation for further studies into bone as a developing system, helping to understand how bone's appearance may be related to its environment, ecology, growth, and locomotion.

Committee: Patrick M. O'Connor (Advisor) Subjects: Anatomy and Physiology; Animal Sciences; Biology; Biomechanics; Biomedical Research; Developmental Biology; Evolution and Development; Histology; Morphology