What characterizes a Hill-Sachs lesion?

• A. A fracture of the radial head
• B. A compression of the TMJ disc
• C. An injury to the bone associated with anterior glenohumeral dislocation
• D. A type of shoulder impingement syndrome

Answer: (C)

A Hill-Sachs lesion is characterized as an injury to the bone that occurs as a result of an anterior dislocation of the glenohumeral joint, which is the shoulder joint. Specifically, it is a compression fracture of the posterolateral aspect of the humeral head. This injury is typically seen when the humeral head impacts against the glenoid rim during dislocation, leading to the characteristic indentation in the bone.

The association of Hill-Sachs lesions with anterior glenohumeral dislocations is significant because it highlights the importance of understanding shoulder biomechanics. When the humeral head dislocates, it can sustain damage that may affect shoulder stability and function, emphasizing the need for proper assessment and treatment in patients with dislocated shoulders.

In contrast, other options reference conditions or injuries that are unrelated to the Hill-Sachs lesion. For example, a fracture of the radial head pertains to the elbow, while compression of the TMJ disc relates to the jaw, and shoulder impingement syndrome describes a different pathological process altogether that involves the compression of structures within the shoulder, typically due to anatomical variations or shoulder positioning during arm elevation.