What is the significance of the costoclavicular test?

• A. Confirms a Rotator Cuff Tear
• B. Indicates Compression of the Sciatic Nerve
• C. Detects Compression at the Costoclavicular Region
• D. Differentiates Between TOS and Cervical Radiculopathy

Answer: (C)

The costoclavicular test is significant because it specifically assesses for the presence of thoracic outlet syndrome (TOS) due to compression in the costoclavicular space. This test evaluates the relationship between the clavicle and the first rib, where structures like the brachial plexus and subclavian vessels can be compressed. During the test, the clinician typically palpates the radial pulse while the patient's shoulder is depressed and retracted. A diminished or absent pulse indicates an increase in compression at this region, suggesting the possibility of TOS originating from anatomical structures in the costoclavicular space.

Various other options relate to conditions that the costoclavicular test does not assess directly. For example, confirming a rotator cuff tear typically involves other clinical tests and imaging rather than evaluating compressive forces in a thoracic outlet context. Meanwhile, the sciatic nerve is located in the lower extremity, and its compression is evaluated through different lumbar and pelvic assessments, not through the costoclavicular region. Lastly, differentiating between TOS and cervical radiculopathy would require a battery of tests addressing upper limb nerve root function and specific neurologic assessments, rather than relying solely on the costoclavicular test.