Thoracic outlet syndrome (TOS) - compression of the neurovascular bundle (brachial plexus, subclavian artery, or subclavian vein) as it passes through the thoracic outlet between the collarbone and first rib - is one of the most misdiagnosed conditions in the upper limb.
Patients often spend years cycling between carpal tunnel workups, cervical MRIs, shoulder scans, and pain clinics before TOS is finally identified.
Yet when correctly diagnosed, 80–90% of cases resolve with conservative physiotherapy.
Here's how we identify and treat it in Johor.
The three subtypes
Neurogenic TOS - brachial plexus compression. Around 95% of TOS cases.
Pain, numbness, tingling, or weakness along the arm, often with specific trigger postures (arms overhead, carrying heavy bags, sleeping with arm above head).
Venous TOS - subclavian vein compression. Arm swelling, heaviness, discolouration.
Less common; sometimes presents acutely with effort thrombosis.
Arterial TOS - subclavian artery compression. Cold, pale arm with reduced pulse.
Rarest and most serious; surgical evaluation usually needed.
This article focuses on neurogenic TOS - the majority of cases and the one physiotherapy addresses.
Typical presentation
- Arm or hand pain, numbness, or tingling - often poorly localised, not fitting a single nerve root pattern.
- Symptoms triggered by overhead work, carrying a bag on that shoulder, or certain sleep positions.
- Weakness in grip strength, especially after sustained arm use.
- Sometimes headache or neck pain.
- Often worse in activities like hair-drying, painting ceilings, or driving with both hands on the wheel.
Why it gets missed
TOS doesn't fit a single nerve root pattern, so radiculopathy workups come back normal. It doesn't usually show on nerve conduction studies unless severe.
MRI of the neck typically normal.
The key tests - Roos test (elevated arm stress test), Adson, Wright - are physical exam manoeuvres, not imaging findings.
Clinicians who don't include them miss the diagnosis.
The conservative programme - 10–12 weeks
Phase 1 (weeks 1–3): reduce outlet pressure
- Postural correction - the archetypal TOS patient is the forward-head, rounded-shoulder, chest-tight pattern. Correct this and symptoms drop by a third within 2 weeks.
- First rib mobilisation - manual or self-mobilisation. The first rib often sits elevated, narrowing the thoracic outlet.
- Scalene muscle release - the anterior and middle scalenes are usually tight and shortened.
- Teach "scapular set" position - shoulder blades back and down, neutral head - to use throughout the day.
Phase 2 (weeks 4–8): strengthen the right things
- Lower trapezius and serratus anterior - the muscles that hold the shoulder blade in a neutral, supported position.
- Deep neck flexors - counter the forward-head load.
- Scapular retraction and depression - against resistance band, multiple angles.
- Avoid aggressive strengthening of the upper trapezius - often already overactive.
Phase 3 (weeks 9–12): integrate and return to function
- Task-specific adaptations - how to lift, carry, sleep, and work without reproducing symptoms.
- Progressive return to overhead activity, carrying, and whatever triggered the original presentation.
- Ongoing self-mobility and strength maintenance (twice weekly).
When surgery is considered
Conservative treatment fails in roughly 10–20% of neurogenic TOS patients. In that subset, surgical decompression (first rib resection, scalenectomy, or both) may be appropriate.
This is a specialty-surgeon decision, usually vascular or thoracic surgery. Most Johor patients who need it are referred to Singapore or KL tertiary centres.
Venous TOS - a caveat
Patients presenting with one arm that's bigger, heavier, or a different colour than the other - especially after vigorous arm activity (sometimes called Paget-Schroetter syndrome or effort thrombosis) - may have venous TOS with associated clot.
This is a medical emergency requiring urgent vascular workup. Physiotherapy is not first-line here.
Typical Johor costs
- Physio course: 10–14 sessions at RM120-250.
- Vascular consultation (private): RM120-250.
- Surgical decompression (if needed): RM 20,000–40,000 private; typically done outside Johor.
How PhysioJohor matches TOS patients
WhatsApp us with: distribution of symptoms, triggers, prior workups, and whether you've had imaging or nerve conduction tests.
Please be explicit if you've had any arm swelling, coldness, or discolouration - those signs shift the triage priority.
We match to a physio with TOS-specific experience; it's not a condition general musculoskeletal physio reliably handles.
Related guide: Physiotherapy in Johor - complete guide