Nazarahari N, et al. - This study was intended to apply inertial measurement units, which offer the sensitivity required to measure the trunk’s subtle movements to evaluate brachial plexus injury and quantify its biomechanical consequences. Researchers estimated six kinematic scores applying inertial measurement units placed on the upper arms and the trunk during nine functional tasks. Both statistical and machine learning techniques were applied to compare the bilateral asymmetry of the kinematic scores of fifteen affected and fifteen able-bodied individuals (controls). The proposed wearable technology was found to be a sensitive and reliable tool for the objective outcome assessment of brachial plexus injury and its biomechanical consequences. It may be beneficial in clinical research and practice, particularly in large cohorts with multiple follow-ups.