Intraskeletal Consistency in Patterns of Vascularity within Bat Limb Bones.

Intraskeletal Consistency in Patterns of Vascularity within Bat Limb Bones.

Andronowski JM; Cole Mary E; Hieronymous TL; Davis RA; Usher Logan R; Cooper LN

Anatomical Record

2021

2021-06-08

Bats are the only mammals to have achieved powered flight. A key innovation allowing for bats to conquer the skies was a forelimb modified into a flexible wing. The wing bones of bats are exceptionally long and dynamically bend with wingbeats. Bone microarchitectural features supporting these novel performance attributes are still largely unknown. The humeri and femora of bats are typically avascular, with the exception of large-bodied taxa (e.g., pteropodid flying foxes). No thorough investigation of vascular canal regionalization and morphology has been undertaken as historically it has been difficult to reconstruct the 3D architecture of these canals. This study augments our understanding of the vascular networks supporting the bone matrix of a sample of bats (n=24) of variable body mass, representing three families (Pteropodidae (large-bodied, Species=6), Phyllostomidae (medium-bodied, Species=2), and Molossidae (medium-bodied, Species=1)). We employed Synchrotron Radiation-based micro-Computed Tomography (SRμCT) to allow for a detailed comparison of canal morphology within humeri and femora. Results indicated that across selected bats, canal number per unit volume is similar independent of body size. Differences in canal morphometry based on body size and bone type appear primarily related to a broader distribution of the canal network as cortical volume increases. Heavier bats display a relatively rich vascular network of mostly longitudinally-oriented canals that are localized mainly to the mid-cortical and endosteal bone envelopes. Taken together, our results suggest that relative vascularity of the limb bones of heavier bats forms support for nutrient exchange in a regional pattern. This article is protected by copyright. All rights reserved.

Bone; Chiroptera; Cortical porosity; Micro-CT; Synchrotron

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journalArticle

1932-8494 1932-8486

NEOMED College of Medicine

Department of Anatomy & Neurobiology

June 2021 List