Impingement syndrome is sometimes called swimmer’s shoulder or thrower’s shoulder. It is caused by the tendons of the rotator cuff becoming impinged as they pass through the shoulder joint.
Symptoms of shoulder impingement include pain which comes on gradually over a period of time. There will be pain at the front and side of the shoulder joint, especially during overhead movements such as in throwing, racket sports and swimming.
There may be pain at the back and front of the shoulder when the arm is held out to the side or abducted and turned outwards into external rotation. Another give away sign of impingement is pain when lifting the arm above 90 degrees, particularly against resistance. See shoulder impingement tests.
What is impingement syndrome?
Shoulder impingement syndrome, which is sometimes called swimmer’s shoulder or thrower’s shoulder, is caused by the tendons of the rotator cuff muscles becoming impinged as they pass through a narrow bony space called the subacromial space. The subacromial space is so called because it is under the arch of the acromion. With repetitive pinching, the tendons become irritated and inflamed.
This can lead to thickening of the tendon which may cause further problems because there is very little free space, so as the tendons become larger, they are impinged further by the structures of the shoulder joint and the muscles themselves.
Impingement Syndrome in itself is not a diagnosis, it is a clinical sign. There are at least nine different diagnoses which can cause impingement syndrome which include bone spurs, rotator cuff injury, labral injury, shoulder instability, biceps tendinopathy and scapula dysfunction. If left untreated, shoulder impingement can develop into a rotator cuff tear.
The supraspinatus muscle is probably the most commonly involved in impingement syndrome of the shoulder.
External shoulder impingement is classified as primary or secondary.
Primary external impingement is usually due to bony abnormalities in the shape of the acromial arch in the shoulder joint. It can sometimes be due to congenital abnormalities known as os acromial, or due to degenerative changes, where small spurs of bone grow out from the arch with age, and impinge on the tendons.
Secondary external impingement is usually due to poor scapular or shoulder blade stabilization which alters the physical position of the acromion, hence causing impingement on the tendons. Is often due to a weak serratus anterior muscle and a tight pectoralis minor muscles. Other causes can include weakening of the rotator cuff tendons due to overuse for example in throwing and swimming, or muscular imbalance with the deltoid muscle and rotator cuff muscles.
This occurs predominantly in athletes where throwing is the main part of the sport, e.g. pitches in baseball or javelin throwers. The under side of the rotator cuff tendons are impinged against the glenoid labrum. This tends to cause pain at the back of the shoulder joint as well as sometimes at the front.
Rest the shoulder from any painful activities or movements. Pain indicates increasing the inflammation and delaying the healing process. Apply ice or cold therapy to the painful area for 10-15 minutes per hour initially reducing to 3 or 4 times a day as pain reduces. Remember to use an ice bag or a towel wrapped around the ice to protect against ice burn.
Seek advice from a sports injury professional who can develop an appropriate rehabilitation program. Return to sport gradually once the pain has eased.
A professional therapist may carry out specific tests and order X-Rays to diagnose what is causing the impingement. A doctor may prescribe anti-inflammatory medication such as Ibuprofen to reduce pain and inflammation. They may discuss the option of directly injected steroids into the subacromial space to reduce inflammation and reduce inflammation in the local area although this is not usually an early option. It is usually recommended after a period of at least 6-12 months.