3-dimensional shoulder complex kinematics and shoulder pain
Second only to low back pain, shoulder pain is the most common musculoskeletal complaint with a reported 20.9% prevalence. Whilst most are given the general diagnosis of ‘impingement,’ the actual pathomechanics are poorly understood. Differences in scapulothoracic joint motion have been reported between symptomatic and asymptomatic shoulders – however, little is known regarding the simultaneous kinematics at the sternoclavicular or acromioclavicular joints. The current study investigated the motion at these 3 joints in symptomatic and asymptomatic individuals.
Symptomatic subjects consistently demonstrated less sternoclavicular posterior rotation. Furthermore, less scapulothoracic upward rotation was observed at 30° and 60° of humerothoracic elevation during both shoulder abduction and scapular plane abduction in the symptomatic individuals.
Despite the small magnitude of the differences in kinematics observed between both groups, these results nonetheless do support the notion that differences in shoulder complex motion does exist between symptomatic and asymptomatic individuals. Further studies perhaps of longitudinal design would be beneficial to determine whether these differences are cause or effect.
> From: Lawrence et al., J Orthop Sports Phys Ther 44 (2014) 636-645. All rights reserved to Journal of Orthopaedic & Sports Physical Therapy. Click here for the Pubmed summary.