JSES - 2026-08-06 - Journal Article
The biomechanics of the sternoclavicular joint: an experimental and computational study.
Irshad TB, Pascoletti G, Zanetti EM
Topics
Key Takeaway
The sternoclavicular joint reaches at least 25° of elevation and 35° of retraction, with peak joint forces reaching 75% of body weight during shoulder motion.
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Summary
This study quantified SCJ kinematics and kinetics using IMU-based motion capture on live subjects combined with an OpenSim musculoskeletal model validated against transcortical pin data and instrumented prosthesis force data. SCJ elevation reached at least 25°, retraction at least 35°, and peak joint reaction forces reached 75% of body weight. IMU-based retraction measurement was identified as unreliable due to skin motion artifact, requiring more invasive tracking methods for accurate retraction quantification.
Key Limitation
The study does not report subject demographics, sample size, or activity levels, making it impossible to assess whether the kinematic and kinetic values are representative of the broader population or specific functional demands.
Original Abstract
BACKGROUND
This study aims to thoroughly investigate the biomechanics of the sternoclavicular joint (SCJ), a key component of the shoulder complex.
METHODS
Inertial sensors were used on live human subjects to measure joint movements during abduction-adduction, flexion-extension, and shrugging. These motion data were then applied to a musculoskeletal model (OpenSim) to analyze the SCJ's range of motion and joint forces. The model was validated using previously published data involving transcortical pins for motion tracking and results from instrumented shoulder prostheses for kinetic comparison.
RESULTS
Findings highlighted the range of motion of
SCJ
at least 25° of elevation, 35° of retraction, with peak reaching 75% of body weight. The model has been validated against experimental results and on the whole it was found able to provide reliable biomechanical information concerning clavicle elevation and SCJ forces; the estimation of clavicle retraction has resulted to be more critical: here the use of inertial measurement units (IMUs) may produce an underestimation of angular displacements due toto skin motion relative to the underlying bones, making more invasive approaches are required.
CONCLUSION
Overall, the study provides biomechanical insights on SCJ biomechanics, and suggests a validated methodology for further analyses.