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In vivo assessment of forearm bone mass and ulnar bending stiffness in healthy men
Author(s) -
Myburgh Kathryn H.,
Zhou LinJuin,
Steele Charles R.,
Arnaud Sara,
Marcus Robert
Publication year - 1992
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650071115
Subject(s) - ulna , forearm , medicine , bone mineral content , moment of inertia , orthodontics , bone mineral , nuclear medicine , osteoporosis , anatomy , physics , quantum mechanics
The 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 ≤ 0.005) with age. Neither BMC nor EI declined with age. The single best predictor of EI was BW ( r 2 = 0.47, p = 0.0001), and further small but significant contributions were made by BMC ( r 2 = 0.53, p = 0.0001) and grip strength ( r 2 = 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.