The pains in posterior compartment of the shoulder joint are most often caused by the posterosuperior impingement, but may also be involved by post- -traumatic lesion of m. infraspinatus and m. teres minor.
The article presents aspects of magnetic resonance imaging of the shoulder joint, with a focus on its dorso-cranial segment. The authors report the clinical and morphological manifestations of the posterosuperior impingement (PSI), which is manifested by acute or chronic pain of the posterior compartment of the shoulder joint. PSI is morphologically characterized by lesions of the rotator cuff in the area of m. infraspinatus and the dorso-caudal part of m. supraspinatus tendon, dorso-cranial labral lesions, and bone marrow edema in the place of contact of tuberculum majus humeri with the cranial part of the glenoid labrum. A short case report mentions other causes of pain in the posterior part of the shoulder joint, namely post-traumatic distension of insertion of m. infraspinatus or m. teres minor and the reverse Bankart lesion. The article also mentions the importance of using the less common ABER (abduction and external rotation) position of the arm to view the posterior caudal lesions of m. supraspinatus at PSI.
Key words: impingement syndrome, magnetic resonance, shoulder joint, rotator cuff.