The Kinematics of Shoulder Impingement: Glenohumeral Joint Positions and the Effects on Rotator Cuff Tendon Clearance

Abstract

The infraspinatus, supraspinatus, and subscapularis were considered when looking at impingement in ten subject anatomical models. The infraspinatus and supraspinatus were found to be the sources of impingement for symptomatic subjects in two representative positions: reaching up behind the back and reaching into the back pocket. The minimum distances were found to be smaller and area of contact between the tissues and the acromion and coracoacromial ligament were found to be larger in symptomatic subjects. These results support that the impingement of these structures may cause symptoms in the subjects.