Shoulder impingement / subacromial impingement / painful arc syndrome
With impingement syndrome, tissue that is located beneath the shoulder roof becomes trapped between the humeral head and the shoulder roof. The pain that occurs is felt mainly when raising the arm.
The word "impingement" is a misleading term. The literal definition is "collision", but in the phrase "impingement syndrome" it usually means "trapping".
Description of condition
The shoulder joint consists of structures such as the shoulder blade and the upper bone of the arm (the humerus). The roof of the shoulder is formed by the shoulder blade and consists of the acromion, the coracoacromial ligament and the coracoid process. The roof of the shoulder is located above the humeral head.
There are muscles, tendons and bursae located between the roof of the shoulder and the humeral head. With impingement syndrome, one or more of these structures become trapped because the humeral head moves too far upward against the roof of the shoulder. There are various causes.
Cause and history
Firstly, the trapping may be caused by certain structures under the roof of the shoulder swelling or taking up more space than normal. This results in them being constricted sooner when the upper arm is raised.
A second cause is that the space under the roof of the shoulder becomes smaller because the humerus moves up too far. This may be caused, for example, by poor functioning of the rotator cuff muscles in the shoulder.
The roof of the shoulder can also have a distorted shape, making the space below it (the subacromial space) smaller so leading to more rapid constriction.
Signs & symptoms
As impingement syndrome is caused by various other problems in the shoulder, the symptoms can differ for each patient. Typical characteristics are pain on the outside of the shoulder, sometimes radiating to the upper arm and in severe cases as far as the hand.
The pain occurs when raising the arm. This is often felt in the range of movement around 90 degrees (see image, movement range B). The end of the movement may also be painful. In addition, the patient experiences pain during rotational movements of the upper arm and when lifting the upper arm against resistance.
The diagnosis of impingement syndrome may be made by a physiotherapist, primary care physician or orthopedic specialist. The diagnosis is made on the basis of the history of symptoms and the results of a physical examination. During the physical examination, the cause of the impingement syndrome is also evaluated. If tendon problems are suspected to be the cause, an ultrasound may be requested. An ultrasound can also be used to rule out other conditions. Further additional testing is not necessary to make a diagnosis.
The treatment is aimed at reducing pain and improving mobility and muscle function. The aim is to increase the subacromial space and so relieve pressure on the affected structures. Training the rotator cuff muscles can play an important role in this process. In addition, stretching exercises may be used to normalize the muscle length of shortened muscle tissue.
If (acute) severe pain is the main problem, the primary care physician or specialist may decide to administer a corticosteroid injection (anti-inflammatories).
Depending on the nature and the aim of the treatment, the physiotherapy treatment can be expected to have an effect on the pain and/or mobility within 3 to 6 weeks. Surgical intervention may be considered if this is not the case, an injection does not provide relief and the symptoms are severe.
Follow the online exercise program here with specially designed exercises for impingement syndrome.
Hyvönen, P. (2003). On the pathogenesis of shoulder impingement syndrome. Oulu: University Press.
Jansen, M.J., Brooijmans, F., Geraets, J.J.X.R., Lenssen, A.F., Ottenheijm, R.P.G., Penning, L.I.F. & Bie, R.A. de (2011). KNGF Evidence Statement. Subacromiale klachten. Supplement bij het Nederlands Tijdschrift voor Fysiotherapie. Jaargang 121, nr. 1.
Nugteren, K. van & Winkel, D. (2007). Onderzoek en behandeling van de schouder. Houten: Bohn Stafleu van Loghum.
Verhaar, J.A.N. & Linden, A.J. van der (2005). Orthopedie. Houten: Bohn Stafleu van Loghum.