Cyriax Release Test | Thoracic Outlet Syndrome Assessment

Thoracic Outlet Syndrome is defined as a neurovascular symptom complex associated with compression of the brachial bundle, which includes the brachial plexus and/or subclavian vessels. This compression may be caused by several anatomical structures in one or more of the following three compartments: the interscalene triangle, the costoclavicular space or retropectoralis minor space.

The Cyriax Release Test is believed to produce a release of tension or compression of the neurovascular bundle of the brachial plexus at all 3 intervals of the thoracic outlet.
According to Brismée et al. in the year 2004, the Cyriax Release Test had a specificity of 97,4% when held for 1 minute and a specificity of 87,8% at 3 minutes. As the authors have not provided any data on sensitivity, the clinical value of this test is still questionable.

To perform the test, have the patient in sitting position. The therapist stands behind the patient and grasps under the forearms holding the elbows at approximately 80-90°, while maintaining the forearms, wrists, and hands in neutral. The therapist then leans the patient’s trunk posteriorly, approximately 15° from vertical, and elevates the patient’s shoulder girdle close to end range. This passive shoulder girdle elevation position of both shoulder girdles is held for up to three minutes.

This test is considered positive if either a release phenomenon occurs or the patient’s familiar symptoms are reproduced.

This test is based on the theory of the release phenomenon, which occurs following decompression of one or more nerve trunks/ cords. Release of the low-level local compression/tension allows for a restoration of neural blood flow and normalization of function, which can cause a spontaneous firing of the large myelinated sensory fibers. It has been suggested that paresthesia is the most common symptom reported with the release phenomenon, followed by numbness, then pain.

21 OF THE MOST USEFUL ORTHOPAEDIC TESTS IN CLINICAL PRACTICE

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Other common tests to assess for TOS are:

• Costoclavicular / Halstead Maneuver
• Morley / Brachial Plexus Compression Test
• Eden / Miliatry Brace Test
• Roos Test / Elevated Arm Stress Test
• Tinel Sign 
• Adson Test
• Wright’s Test

Brismée, J. M., Gilbert, K., Isom, K., Hall, R., Leathers, B., Sheppard, N., … & Sizer, P. (2004). Rate of false positive using the cyriax release test for thoracic outlet syndrome in an asymptomatic population. Journal of Manual & Manipulative Therapy, 12(2), 73-81.