دانلود کتاب بیماری های اسکلتی عضلانی 2021-2024 – تصویربرداری تشخیصی

Learning Objectives • To know the types of glenohumeral instability and anatomic factors for the development of glenohumeral instability. • To understand the concept of the glenoid track and the engaging Hill-Sachs lesion. • To understand the MR appearance of SLAP tears, overhead thrower labral tears, and the labral tears associated with spinoglenoid notch cysts. • To understand how to distinguish labral tears from normal labral variants. Glenohumeral instability is the inability to keep the humeral head centered in the glenoid fossa. Glenohumeral instability can be classified according to etiology and direction of instability. Glenohumeral instability can be classified into static instabilities, dynamic instabilities, and voluntary dislocation. Static instability is associated with significant structural alteration of the shoulder, for example, large rotator cuff tears or a glenoid dysplasia with consecutive static decentering of the humeral head. Dynamic instability is the classic form of instability, commonly caused by trauma, and is usually associated with injuries to the labrum, to the glenohumeral ligaments, and often with fractures of the glenoid rim. Dynamic instability may also be associated with general hyperlaxity. Glenohumeral instability may be unidirectional (anterior instability or posterior instability) or multidirectional. Multidirectional instability is affecting a minority of patients. The classification in traumatic instability and atraumatic instability is important from an imaging perspective. Both instabilities are characterized by recurrent dislocations of the glenohumeral joint. However, in traumatic instabilities, structural changes such as labral, ligamentous, and bony lesions are highly prevalent. In atraumatic instabilities the glenohumeral joint may not exhibit any injuries