What is shoulder Impingement?
Shoulder impingement is perhaps the most common shoulder condition seen in clinic. As pictured below, the subacromial space is formed between the acromion and the head of the humerus, in this small space lie some important structures. The rotator cuff tendons pass through this space, they collectively provide a compressive force to the humerus to keep the shoulder joint stable. The sub-acromial bursa is a fluid-filled sac, its role is to reduce friction between muscles and tendons moving against the bones. During shoulder elevation, either one or both structures can be compressed between the humerus and the acromion, this is referred to shoulder impingement.
Who suffers from shoulder impingement?
Those who perform repeated overhead movements are more likely to develop shoulder impingement. In the younger population, this may be exhibited in throwing athletes, swimmers, weightlifters, tennis players or golfers. In the older population it may be more so seen manual labour workers and painters.
What causes shoulder impingement?
Many factors can attribute to the development of shoulder impingement. The research has classified these factors as either primary or secondary causes of shoulder impingement. Primary impingement refers to the structure of one’s shoulder anatomy. Some people are born with a hooked acromion as pictured below, this reduces the sub-acromial space and may increase the likelihood of developing impingement. Degenerative conditions such as osteoarthritis may lead to the development of bony spurs which also narrow the sub-acromion space and contribute to shoulder impingement.
Secondary impingement addresses biomechanical factors which contribute to the development of shoulder impingement. It is these factors your Physiotherapist is trained to assess and treat. These may include lack of rotator cuff strength/rotator cuff tendon pathology, poor scapular stability/motor control, shoulder instability, biceps tendon pathology or lack of shoulder and thoracic mobility.