Shoulder impingement syndrome describes a situation where the rotator cuff tendons and sub-acromial bursa become impinged in the sub-acromial space. The tendons and bursa may then become inflamed and painful which results in restriction of movement and weakness around the shoulder.
anatomy of the shoulder
To understand shoulder impingement syndrome some basic knowledge about the anatomy around the shoulder is necessary.
rotator cuff muscles
A group of 4 small muscles run from the shoulder blade to the top of the arm bone form a rotator cuff tendon. To get to the arm bone the tendon passes through the sub-acromial space.
The sub-acromial space is a narrow space between the accordion and the top of the upper arm bone (humerus). Located in this space are the rotator cuff tendons and the sub-acromial bursa (a sack of fluid that acts as a cushion).
Anything which causes narrowing of the sub-acromial space will cause the tendon and bursa to become impinged.
Possible causes of sub-acromial narrowing and shoulder impingement include:
- Inflammation in the sub-acromial space caused by trauma
- Boney spurs or variations in the shape of the acromion
- Overuse - often due to repetitive reaching overhead or lifting
- Thickening or calcification of the coraco-acromial ligament
- Poor mechanics of the shoulder blade and arm during movement – often caused by weakness of the shoulder stabilizing muscles
signs and symptoms
Symptoms of shoulder impingement syndrome can include:
- Pain in the top of the arm usually worsens if you try to lift your arm up in the air.
- Pain may occur at rest and be worse at night particularly if lying on the affected shoulder
- Activities that worsen the symptoms include lifting, putting up washing, overhead arm activities, pushing down through the arm, lying on the shoulder
- Movement may be restricted by pain and be associated with clicking or a painful arc
Shoulder Impingent can usually be diagnosed by taking a history and with physical examination.
Physical examination should consider range of movement, strength, biomechanics of the shoulder blade and arm bone and palpation. Specific tests may indicate the presence of impingement.
Plain x-rays and an ultrasound may be of use in defining the state of the acromion and the tendons and bursa in the sub-acromial space.
There are two phases of management of shoulder impingement syndrome.
1. reducing symptoms in the acute phase
In this phase different treatments are used to reduce pain and maintain function.
These may include:
- Use of ice to reduce inflammation
- Taping to correct biomechanics of the shoulder or off load rotator cuff muscles
- Soft tissue massage and trigger point therapy to reduce tone in the rotor cuff muscles and maintain mobility of the tissues around the
- Joint mobilization used to improve the alignment of the joints and reduce the potential for impingement
- Dry needling may be useful to reduce muscle tone around the shoulder and promote better biomechanics
- Stretches both in the treatment room and at home form an important part of this phase
- Activity modification in daily activities and at work
- Treatment of the neck may be indicated where this is a component of the problem
2. rehabilitation and return to function
This phase begins as acute symptoms are settling and movement is improving. It may include some of the following modalities:
- Pilates based strengthening
- Home exercise program of stretching and strengthening
- Functional retraining for return to work or sport – these training needs to strengthen around the shoulder in movement patterns which simulate these activities