Acromion Process and Head of Humerus. Permission Joseph E. Muscolino. Kinesiology - The Skeletal System and Muscle Function, 3rd ed. Elsevier, 2017).

Six Causes of Shoulder Impingement Syndrome – Part 3

Another reason for shoulder impingement syndrome to occur is insufficient elevation of the clavicle. Most of scapular upward rotation is actually caused by elevation of the clavicle at the sternoclavicular joint, so if clavicular elevation is prevented for any reason, shoulder impingement syndrome can occur.