A novel experimental design for the measurement of metacarpal bone loading and deformation and fingertip force

PeerJ

article

Szu-Ching Lu¹  Evie E. Vereecke²  Alexander Synek³  Dieter H. Pahr³  Tracy L. Kivell¹ 

[1] Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent;Department of Development and Regeneration, University of Leuven;Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology;Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences;Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology

关键词: Hand;    Biomechanics;    Force;    Strain;   

DOI  :  10.7717/peerj.5480

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background Musculoskeletal and finite element modelling are often used to predict joint loading and bone strength within the human hand, but there is a lack of in vitro evidence of the force and strain experienced by hand bones. Methods This study presents a novel experimental setup that allows the positioning of a cadaveric digit in a variety of postures with the measurement of force and strain experienced by the third metacarpal. The setup allows for the measurement of fingertip force as well. We tested this experimental setup using three cadaveric human third digits in which the flexor tendons were loaded in two tendon pathways: (1) parallel to the metacarpal bone shaft, with bowstringing; (2) a semi-physiological condition in which the tendons were positioned closer to the bone shaft. Results There is substantial variation in metacarpal net force, metacarpal strain and fingertip force between the two tendon pathways. The net force acting on the metacarpal bone is oriented palmarly in the parallel tendon condition, causing tension along the dorsum of the metacarpal shaft, while the force increases and is oriented dorsally in the semi-physiological condition, causing compression of the dorsal metacarpal shaft. Fingertip force is also greater in the semi-physiological condition, implying a more efficient grip function. Inter-individual variation is observed in the radioulnar orientation of the force experienced by the metacarpal bone, the fingertip force, and the strain patterns on the metacarpal shaft. Conclusion This study demonstrates a new method for measuring force and strain experienced by the metacarpal, and fingertip force in cadaveric digits that can, in turn, inform computation models. Inter-individual variation in loads experienced by the third digit suggest that there are differences in joint contact and/or internal bone structure across individuals that are important to consider in clinical and evolutionary contexts.

【 授权许可】

CC BY