Lumbar Vertebral Body Bone Microstructural Scaling in Small to Medium-Sized Strepsirhines
Article first published online: 27 JAN 2013
Copyright © 2012 Wiley Periodicals, Inc.
The Anatomical Record
Volume 296, Issue 2, pages 210–226, February 2013
How to Cite
Fajardo, R. J., Desilva, J. M., Manoharan, R. K., Schmitz, J. E., Maclatchy, L. M. and Bouxsein, M. L. (2013), Lumbar Vertebral Body Bone Microstructural Scaling in Small to Medium-Sized Strepsirhines. Anat Rec, 296: 210–226. doi: 10.1002/ar.22632
- Issue published online: 27 JAN 2013
- Article first published online: 27 JAN 2013
- Manuscript Accepted: 16 OCT 2012
- Manuscript Received: 4 SEP 2012
- American Museum of Natural History, the Museum of Comparative Zoology at Harvard University
- lumbar vertebra;
- trabecular bone;
- cortical bone;
Bone mass, architecture, and tissue mineral density contribute to bone strength. As body mass (BM) increases any one or combination of these properties could change to maintain structural integrity. To better understand the structural origins of vertebral fragility and gain insight into the mechanisms that govern bone adaptation, we conducted an integrative analysis of bone mass and microarchitecture in the last lumbar vertebral body from nine strepsirhine species, ranging in size from 42 g (Microcebus rufus) to 2,440 g (Eulemur macaco). Bone mass and architecture were assessed via µCT for the whole body and spherical volumes of interest (VOI). Allometric equations were estimated and compared with predictions for geometric scaling, assuming axial compression as the dominant loading regime. Bone mass, microarchitectural, and vertebral body geometric variables predominantly scaled isometrically. Among structural variables, the degree of anisotropy (Tb.DA) was the only parameter independent of BM and other trabecular architectural variables. Tb.DA was related to positional behavior. Orthograde primates had higher average Tb.DA (1.60) and more craniocaudally oriented trabeculae while lorisines had the lowest Tb.DA (1.25), as well as variably oriented trabeculae. Finally, lorisines had the highest ratio of trabecular bone volume to cortical shell volume (∼3x) and while there appears to be flexibility in this ratio, the total bone volume (trabecular + cortical) scales isometrically (BM1.23, r2 = 0.93) and appears tightly constrained. The common pattern of isometry in our measurements leaves open the question of how vertebral bodies in strepsirhine species compensate for increased BM. Anat Rec, 2013. © 2013 Wiley Periodicals, Inc.