American Board of Internal Medicine (ABIM) Certification Practice Exam

What clinical finding is characteristic of acromioclavicular joint degeneration?

1. Pain elicited on abduction beyond 120 degrees

2. Pain on flexion

3. Limited shoulder extension

4. Instability of the shoulder joint

The correct answer is: Pain elicited on abduction beyond 120 degrees

The characteristic clinical finding associated with acromioclavicular joint degeneration is pain elicited on abduction beyond 120 degrees. This pain occurs because, during abduction past this angle, there is increased movement and strain on the acromioclavicular joint. The degeneration of this joint leads to inflammation and pain as the muscle and tendons around the joint are put under greater tension, resulting in discomfort that can limit a patient’s range of motion. Patients may also experience discomfort with other shoulder movements; however, the specific pain on abduction beyond 120 degrees is a classic indication of issues with the acromioclavicular joint. This distinguishes it from other potential shoulder problems that might manifest through different movements or range of motion limitations. The other options provide alternative movements or symptoms but do not specifically indicate the pain or mechanics directly associated with acromioclavicular joint degeneration. For instance, while pain on flexion could be present, it is not a hallmark of this joint's degeneration specifically. Limited shoulder extension is more commonly associated with rotator cuff or glenohumeral problems. Instability of the shoulder joint might suggest a different issue entirely, such as labral tears or shoulder dislocations, rather than a degenerative process affecting the