Impingement syndrome of the shoulder (“collision”; synonyms: Bursitis subacromialis; bursitis subdeltoidea; tightness syndrome; tightness syndrome; periarthropathia humeroscapularis; rotator cuff syndrome; shoulder tightness syndrome; subacromial syndrome (SAS for short); subacromial tightness syndrome; subacromial pain syndrome; supraspinatus syndrome; ICD-10-GM M75. 4: Impingement syndrome of the shoulder) refers to a narrowing of the sliding space of the tendons of the rotator cuff muscles (group of four muscles whose tendons, together with the ligamentum coracohumerale, form a coarse tendon cap that encompasses the shoulder joint) and the shoulder bursa (bursa subacromialis) between the humeral head (upper end of the humerus bone) and the acromion. Because of the tightness, pain is experienced during abduction movements (lateral leading/spreading away) of the arm.
The causes are manifold. Most often, impingement syndrome results from degeneration (wear/tear) or entrapment of capsular or tendon material. Impingement syndrome itself is among the most common causes of shoulder pain (omalgia).
According to the cause, the following forms of impingement syndrome of the shoulder are distinguished:
- Outlet impingement (primary impingement) – morphological (“affecting the shape”)/mechanical functional disorder, e.g., caused by a bone spur.
- Non-outlet impingement (secondary impingement) – ligamentous (“concerning the ligaments”) or neuromuscular (“concerning the nerves and muscles”) functional disorder, e.g., due to bursitis (chronic inflammation of the bursa) or rotator cuff rupture (tear of the rotator cuff)
Frequency peak: impingement syndrome of the shoulder can occur in any age group. Signs of degeneration in the rotator cuff develop from the age of 30. However, these do not immediately cause clinical symptoms. However, if additional damage occurs in this area, painful irritation of the tendons and/or gliding tissue may occur. The maximum incidence is around the age of 50.
The prevalence (disease frequency) is 10-12% (in Germany).
Course and prognosis: If impingement syndrome of the shoulder is not treated, it leads to chronic tendon irritation. The sooner therapy is started, the more favorable the prognosis. Often, different therapy options are combined or applied one after the other. It is not uncommon for several weeks to months to pass before the affected person is free of symptoms.
