One of the most common causes of shoulder pain and functional limitation.

It is a disease related to the rotator cuff, ie tendons of four muscles that, with the deltoid and scapular stabilizers, allow shoulder’s combined complex movement (‘circumduction’): supraspinatus, infraspinatus, subscapularis, and minor teres. These four tendons realizing the so-called rotator cuff flow under the coracoacromial arch, which is inextensible, in a space that is placed between the acromial bone (a scapular process) and the proximal head of the humerus.

The rotator cuff insertion covers humeral head. When the subacromial space is narrowed (for various reasons), this fact creates a discrepancy between container and contents, tendons resulting compressed: it generates a friction on them under the acromioclavicular-coracoid arch, friction that causes pain and progressive erosion of the tendons and results in pain and functional progressive limitation of the shoulder up to the clinical situation of ‘pseudo-paralysis’ in case of total lesion of the rotator cuff, with related complete loss of function and consequent muscle pain, inability to raise the arm for decentralization and cranial migration of the humeral head.

Neer in 1972 was the first to describe the stages of this disease: • the first stage concerns young people under 25 years and is characterized by edema and hemorrhage in sliding tendons (sottoacromion-deltoid space); • the second stage affects people between 25 and 40 years, and the typical changes are fibrosis of the cuff and tendinitis of the long head of the biceps and supraspinatus tendon; • the third stage occurs after age 40, presents more serious tendon injuries (possibly breaking) and progressive appearance of bone spurs.

Treatment in earlier stages is conservative (medical care, physical therapy, anti-inflammatory and infiltration with hyaluronic acid) or arthroscopic surgery (with bone resection; acromioplasty, coracoplasty and, sometimes, resection of the lateral end of the clavicle).

Pain may be acute or chronic and radiated to the shoulder, and particularly evident during an effort with his arm raised. One can evaluate the integrity of the supraspinatus tendon with Jobe’s maneuver, as well as with Erls test, and in case of positivity the patient should be sent urgently to the attention of the orthopedic specialist.

In subacromial impingement a particularly important but indirect role is played by the long head of biceps tendon: especially after age 50, this tendon, which acts as a flexor of the arm working and runs over the bicipital groove like over a pulley, degenerates progressively becoming often too large and unstable, and causing pain in the shoulder frequently and wrongly attributed to a suacromial impingement; when medical care and physical are uneffective, its surgical treatment can be expected, associated to subacromial decompression, with two main surgical options: clb tenotomy from its proximal insertion, or –in sporting and high demanding patients- tenodesis (distal to the subscapularis) with interference screw, both minimally invasive surgical and high efficient operations.