Thoracic Outlet Syndrome: Provocative Tests, First Rib Mobilization, and Scalene Decompression
In short
Neurogenic Thoracic Outlet Syndrome compresses the brachial plexus at the interscalene triangle; first rib depression and scalene release restore neurovascular glide.
In this guide (4 sections)
Pathoanatomy of Neurovascular Compression in the Thoracic Outlet
Thoracic Outlet Syndrome (TOS) encompasses a constellation of symptoms caused by compression of the neurovascular bundle (the brachial plexus trunks and subclavian vessels) as they traverse the cervico-axillary canal toward the upper extremity. TOS is classified into Neurogenic TOS (NTOS, representing > 90% to 95% of cases), Venous TOS (Paget-Schroetter syndrome), and Arterial TOS.
Neurogenic compression occurs within three distinct anatomical bottlenecks: the Interscalene Triangle (between the anterior and middle scalenes and superior first rib), the Costoclavicular Space (between the clavicle and first rib), and the Subcoracoid / Pectoralis Minor Space. Chronic drooping shoulders, accessory breathing using scalenes, or a congenital cervical rib narrow these spaces, producing medial cord ulnar paresthesias (C8-T1 distribution) and hand intrinsic atrophy.
Provocative Physical Examination Test Battery Matrix
| Provocative Test | Patient Testing Maneuver | Positive Test Finding | Anatomical Entrapment Site | |
|---|---|---|---|---|
| Roos Elevated Arm Stress Test (EAST) | Shoulders abducted 90 deg, externally rotated; open/close hands for 3 mins | Unable to maintain 3 mins; severe arm heaviness, tingling, dropped arms | Global screening; highest sensitivity (~85%) for NTOS | |
| Adson Maneuver | Extend neck, rotate head toward symptomatic side; inhale deep and hold | Radial pulse diminishes/disappears; paresthesia reproduction | Interscalene Triangle compression by anterior scalene | |
| Wright Hyperabduction Test | Arm hyperabducted to 180 degrees with external rotation | Radial pulse obliteration or reproduction of arm numbness | Subcoracoid / Pectoralis Minor compression space | |
| Costoclavicular (Military) Maneuver | Shoulders drawn downward and backward (military attention posture) | Compression symptoms reproduced; pulse dampening | Costoclavicular space narrowing between clavicle and 1st rib | |
| First Rib Springing Test | Passive inferior-posterior pressure applied over superior 1st rib | Hypomobile, rigid first rib reproducing familiar arm ache | Identifies elevated, subluxated first rib requiring mobilization |
Manual First Rib Mobilization and Scalene Decompression Protocols
- Passive First Rib Inferior Depression Mobilization: Seat the patient with head side-bent toward the affected side to slacken scalenes; place your lateral index finger webspace over the superior-posterior aspect of the first rib; deliver gentle, rhythmic inferior-medial oscillatory mobilizations on exhalation to depress the rib.
- Scalene and Pectoralis Minor Soft-Tissue Release: Perform gentle manual myofascial trigger-point release along the anterior and middle scalene bellies; instruct the patient to breathe diaphragmatically to suppress chronic scalene accessory muscle overactivity.
- Lower Trapezius and Scapular Elevation Strengthening: Prescribe prone-Y raises, scapular clocks, and serratus anterior punches; elevating a depressed, downwardly rotated scapula unloads the brachial plexus from being draped over a rigid first rib.
Frequently Asked Questions
What is Thoracic Outlet Syndrome and why does it make fingers numb?
Thoracic Outlet Syndrome happens when the bundle of nerves and blood vessels traveling from your neck into your arm gets pinched in tight spaces near your collarbone and top rib. This causes numbness, tingling, and aching pain running down into your ring and pinky fingers.
What is the Roos test for pinched neck and shoulder nerves?
In the Roos test, you hold both arms up like a goalpost and slowly open and close your hands for 3 full minutes. If your arm becomes heavy, weak, numb, or you cannot keep your hands up for the full 3 minutes, it strongly indicates Thoracic Outlet Syndrome.
How does a physiotherapist move your first rib?
Your first rib sits high up under your collarbone right next to your neck. A therapist uses the side of their hand to gently push that rib downward while you exhale, instantly opening up space for trapped nerves and blood vessels to breathe.
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