Overview
This lecture explains the Roos or elevated arm stress test for diagnosing thoracic outlet syndrome (TOS), discussing its procedure, diagnostic value, and interpretation.
Thoracic Outlet Syndrome (TOS)
- TOS is a neurovascular symptom complex caused by compression of the brachial bundle (brachial plexus and/or subclavian vessels).
- Compression may occur in one or more of three compartments: interscalene triangle, costoclavicular space, or retropectoralis minor space.
Roos (Elevated Arm Stress) Test
- The Roos test stresses all three anatomical intervals, tensing arteries, veins, and nerves.
- To perform: patient sits with head neutral, arms abducted and externally rotated to 90°, elbows flexed to 90°.
- Patient repeatedly flexes and extends fingers for up to three minutes.
- Examiner observes for dropping of the extremity (indicates fatigue/arterial compromise), color changes, and onset of symptoms.
- Test is positive if the patient cannot maintain arm elevation for 3 minutes or if symptoms are induced.
Diagnostic Value
- Roos test sensitivity is 84% and specificity is 30% (according to Gillard et al., 2001).
- Test has low clinical value due to low specificity and lack of MRI confirmation in referenced study.
Key Terms & Definitions
- Thoracic Outlet Syndrome (TOS) — Compression of nerves and/or blood vessels in the thoracic outlet area.
- Brachial Plexus — Network of nerves supplying the arm.
- Subclavian Vessels — Major blood vessels (artery and vein) passing under the clavicle.
- Interscalene Triangle — Space between neck muscles where nerves/vessels can be compressed.
- Costoclavicular Space — Area between the clavicle and first rib.
- Retropectoralis Minor Space — Area beneath the pectoralis minor muscle.
- Sensitivity — Ability of a test to identify true positives.
- Specificity — Ability of a test to identify true negatives.
Action Items / Next Steps
- Review the assessment ebook or mobile app for additional TOS tests.
- Practice performing the Roos test according to the described procedure.