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In vivo assessment of forearm bone mass and ulnar bending stiffness in healthy menThe cross-sectional bending stiffness EI of the ulna was measured in vivo by mechanical resistance tissue analysis (MRTA) in 90 men aged 19-89 years. MRTA measures the impedance response of low-frequency vibrations to determine EI, which is a reflection of elastic modulus E and moment of inertia I for the whole ulna. EI was compared to conventional estimates of bone mineral content (BMC), bone width (BW), and BMC/BW, which were all measured by single-photon absorptiometry. Results obtained from the nondominant ulna indicate that BW increases (r = 0.27, p = 0.01) and ulnar BMC/BW decreases (r = -0.31, p < or = 0.005) with age. Neither BMC nor EI declined with age. The single best predictor of EI was BW (r2 = 0.47, p = 0.0001), and further small but significant contributions were made by BMC (r2 = 0.53, p = 0.0001) and grip strength (r2 = 0.55, p = 0.0001). These results suggest that the resistance of older men to forearm fracture is related to age-associated changes in the moment of inertia achieved by redistributing bone mineral farther from the bending axis. We conclude that the in vivo assessment of bone geometry offers important insights to the comprehensive evaluation of bone strength.
Document ID
20050000575
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Myburgh, K. H.
(Musculoskeletal Research Laboratory, VA Medical Center Palo Alto, California)
Zhou, L. J.
Steele, C. R.
Arnaud, S.
Marcus, R.
Date Acquired
August 22, 2013
Publication Date
November 1, 1992
Publication Information
Publication: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
Volume: 7
Issue: 11
ISSN: 0884-0431
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Musculoskeletal

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