Thoracic Outlet Syndrome
Numbness, tingling or aching down the arm can come from the thoracic outlet rather than the hand. Assessment to find the cause and a plan to get to the bottom of it.
- Certified Hand Therapist (CHT)
- Consultant Hand Therapist
- Hand, wrist & upper limb specialist
What is Thoracic Outlet Syndrome?
Thoracic outlet syndrome (TOS) refers to a group of conditions caused by compression of the neurovascular structures (the brachial plexus, subclavian artery and subclavian vein) as they pass through the thoracic outlet: the space between the collarbone and the first rib. Neurogenic TOS (compression of the brachial plexus) is by far the most common form. Arterial and venous TOS are rarer but more serious conditions requiring urgent vascular assessment.
Neurogenic TOS is frequently misdiagnosed or diagnosed late due to its variable and complex presentation. Symptoms can mimic carpal tunnel syndrome, cervical radiculopathy, rotator cuff pathology and other conditions. Specialist assessment is essential for accurate diagnosis and Hand Therapy is the primary treatment for most cases.
What you might notice
- Pain, aching and heaviness in the shoulder, arm and hand. Often widespread and difficult to localise
- Finger numbness and tingling
- Symptoms provoked by overhead arm positions, sustained shoulder depression or prolonged computer use
- Weakness of grip
- Worsening of symptoms when carrying bags or heavy loads on the affected side
- In vascular TOS: arm swelling, colour change or a feeling of the arm 'going to sleep' rapidly
Why it happens
- Postural factors: forward head posture and rounded shoulders narrowing the thoracic outlet
- Cervical rib: an accessory rib, present in approximately 0.5% of the population
- Hypertrophy of the neck muscles: common in overhead athletes and heavy lifters
- Repetitive overhead activities compressing the neurovascular structures
- Previous clavicle or first rib fracture causing callus formation within the thoracic outlet
- Prolonged carrying of heavy loads on the shoulder compressing the outlet
How it's treated
After a thorough assessment, a personalised treatment plan is built around your needs and goals.
Postural correction is the cornerstone of neurogenic TOS management. Ms Razo assesses posture in detail and provides education and targeted exercises to correct the primary postural drivers of thoracic outlet compression.
Tightness of certain muscles in the upper quadrant is a key contributor to thoracic outlet narrowing. Ms Razo prescribes and focused programme aimed at reducing compressive forces on the brachial plexus and neurovascular structures.
Neural therapeutic techniques reduce intraneural tension and improve nerve mobility through the thoracic outlet. Ms Razo incorporates these carefully into the treatment programme, progressing as your symptoms improve.
Progressive strengthening of the shoulder girdle supports the neurovascular structures and reduces their compression. Ms Razo addresses and provides advice on the provocative factors ocurring in daily life.
Common questions
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TOS is primarily a clinical diagnosis based on a detailed history and specific provocation tests. Imaging including chest X-ray (to identify a cervical rib), MRI and nerve conduction studies may be used to support the diagnosis and exclude other conditions. TOS is frequently misdiagnosed as carpal tunnel syndrome, cervical radiculopathy or shoulder pathology, making specialist assessment important.
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The majority of neurogenic TOS cases are managed non-operatively with specialist Hand Therapy, postural correction and activity modification. Surgery (first rib resection or scalenectomy) is reserved for cases that have failed a thorough course of non-operative treatment. Vascular TOS involving arterial or venous compression typically requires earlier surgical consideration.
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TOS and carpal tunnel syndrome can coexist as a double crush phenomenon, where compression of the nerve at one level (the thoracic outlet) increases its sensitivity to compression at another level (the carpal tunnel). Both conditions can cause hand numbness and tingling, but affect different nerve distributions and are distinguished by careful clinical assessment. If you have been treated for carpal tunnel syndrome without full resolution of symptoms, TOS should be considered.
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Recovery from neurogenic TOS with conservative management typically takes a number of months alongside consistent specialist Hand Therapy and home programme compliance. Postural habits accumulated over years take time to correct, and nerve sensitisation can be slow to resolve. Patience and commitment to the rehabilitation programme are important. Most patients achieve significant symptom improvement with thorough non-operative management.
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Clinically reviewed by Ms Michelle Razo CHT · May 2026