Thoracic Outlet Syndrome.
What is thoracic outlet syndrome?
Thoracic outlet syndrome (TOS) is a group of conditions caused by compression of the neurovascular structures — the brachial plexus nerve bundle, the subclavian artery or the subclavian vein — as they pass through the thoracic outlet. The thoracic outlet is the narrow space between the clavicle and first rib through which these structures travel from the neck into the arm, and any reduction in this space can produce compression symptoms in the shoulder, arm and hand.
TOS is one of the most frequently misdiagnosed conditions in musculoskeletal practice. Its symptom pattern overlaps substantially with cervical radiculopathy, carpal tunnel syndrome, brachial plexus injuries and cervical disc herniation — conditions that are more commonly considered by clinicians, and which are frequently diagnosed and treated in TOS patients without improvement because the actual site of compression has been missed.
Types of thoracic outlet syndrome
TOS can be classified into different types based on the structures being compressed: neurogenic TOS — nerve compression — is most common, presenting in approximately 95% of TOS cases. Vascular TOS involves compression of the subclavian artery or vein. Nonspecific TOS is a diagnosis of exclusion.
What causes thoracic outlet syndrome?
The thoracic outlet is a fixed space. Anything that reduces its dimensions or increases the volume of structures passing through it can produce TOS. The most common contributing factors are:
What are the symptoms?
TOS can cause pain in the shoulders and neck, heaviness, and numbness down the arm into the fingers. Symptoms are typically worse when the arm is elevated. Overhead positions — reaching into a cupboard, blow-drying hair, swimming — are classically aggravating because elevation of the arm rotates the clavicle and further narrows the costoclavicular space. Carrying a heavy bag on the affected shoulder, prolonged typing with arms forward, and sustained neck positions that load the scalenes are also common aggravating activities.
The combination of positional aggravation with overhead activities and the ulnar hand distribution is the clinical pattern most useful for distinguishing neurogenic TOS from cervical radiculopathy — which is typically more aggravated by neck movement than arm position.
How is it diagnosed?
Diagnosis involves clinical examination including specific tests like the Adson's manoeuvre to assess nerve or vascular compression, imaging such as X-rays or MRIs to visualise anatomical structures and potential anomalies such as cervical ribs, nerve conduction studies to evaluate nerve function, and vascular tests such as Doppler ultrasound or angiography to examine blood flow.
Provocative clinical tests — including the Elevated Arm Stress Test (EAST or Roos test), the upper limb tension test, the costoclavicular test and Adson's test — reproduce symptoms by stressing the relevant neurovascular structures. No single test has high sensitivity and specificity, and the clinical diagnosis of TOS relies on pattern recognition across the history, examination and test findings. Nerve conduction studies are frequently normal in neurogenic TOS — the compression is often positional and intermittent rather than producing the sustained axonal damage that NCS detects. MRI of the thoracic outlet with provocative positioning can demonstrate compression directly.
How can physiotherapy help?
Physiotherapy is the primary and most effective treatment for neurogenic TOS in the majority of cases. The physiotherapy approach addresses the postural and muscular contributors that are reducing the thoracic outlet dimensions.
Postural correction is the foundation — specifically addressing the forward head posture, protracted scapulae and thoracic kyphosis that narrow the costoclavicular and interscalene spaces. Thoracic extension mobility, scapular retraction and depression strengthening, and deep cervical flexor retraining are the primary interventions. Clinical Pilates is an excellent environment for this work — combining thoracic extension, scapular control and body awareness training in positions that can be modified to avoid provocative arm elevation in the early phases.
Scalene and pectoralis minor stretching directly reduces the muscular compression on the brachial plexus and subclavian vessels. Scalene stretching requires care — overly aggressive stretching can temporarily worsen symptoms and must be introduced gradually.
Neural mobilisation — gentle brachial plexus gliding exercises — reduces the mechanosensitivity of the compressed nerves and improves their capacity to glide freely through the thoracic outlet during arm movement.
Real time ultrasound assists in identifying and retraining the deep cervical and scapular muscles whose dysfunction contributes to thoracic outlet narrowing. Dry needling of the scalenes, pectoralis minor and subclavius provides symptomatic relief and reduces the muscle tension that is compressing the neurovascular bundle.
Ergonomic assessment and modification — workstation height, keyboard position, monitor placement, and sleeping position — addresses the environmental contributors that perpetuate the postural loading pattern.
For vascular TOS or TOS with a significant anatomical contributor (cervical rib, fibromuscular band) that has not responded to physiotherapy, surgical referral is appropriate. First rib resection and scalenectomy are the most common surgical procedures.
Our physiotherapists Yulia Khasyanova and Mauricio Bara both have experience in complex upper limb and nerve conditions and are members of the Australian Physiotherapy Association.
To book or find out more, call us on 07 3706 3407 or book online below. We see patients from across Brisbane's southside including Tarragindi, Coorparoo, Holland Park, Greenslopes and Mt Gravatt.
Thoracic outlet syndrome (TOS) is a group of conditions caused by compression of the neurovascular structures — the brachial plexus nerve bundle, the subclavian artery or the subclavian vein — as they pass through the thoracic outlet. The thoracic outlet is the narrow space between the clavicle and first rib through which these structures travel from the neck into the arm, and any reduction in this space can produce compression symptoms in the shoulder, arm and hand.
TOS is one of the most frequently misdiagnosed conditions in musculoskeletal practice. Its symptom pattern overlaps substantially with cervical radiculopathy, carpal tunnel syndrome, brachial plexus injuries and cervical disc herniation — conditions that are more commonly considered by clinicians, and which are frequently diagnosed and treated in TOS patients without improvement because the actual site of compression has been missed.
Types of thoracic outlet syndrome
TOS can be classified into different types based on the structures being compressed: neurogenic TOS — nerve compression — is most common, presenting in approximately 95% of TOS cases. Vascular TOS involves compression of the subclavian artery or vein. Nonspecific TOS is a diagnosis of exclusion.
- Neurogenic TOS — by far the most common type — produces pain, numbness, tingling and weakness in the arm and hand from compression of the lower trunk of the brachial plexus (C8 and T1 nerve roots). The symptom distribution typically affects the ulnar side of the forearm and hand — the ring and little fingers and medial forearm — distinguishing it from C6 and C7 radiculopathy which produces symptoms more on the radial (thumb) side.
- Arterial TOS — compression of the subclavian artery — produces ischaemic symptoms: arm pallor, coldness, fatigue and pain with use that improves with rest. It is the least common type but potentially the most serious, carrying risk of arterial thrombosis and distal embolisation. Arterial TOS typically occurs in the context of a cervical rib or bony anomaly and often requires surgical management.
- Venous TOS — compression of the subclavian vein — produces arm swelling, cyanosis, heaviness and distended superficial veins, classically after vigorous upper arm activity in young athletes (Paget-Schroetter syndrome or effort thrombosis). It also often requires surgical or interventional management.
What causes thoracic outlet syndrome?
The thoracic outlet is a fixed space. Anything that reduces its dimensions or increases the volume of structures passing through it can produce TOS. The most common contributing factors are:
- Postural factors — forward head posture, rounded shoulders and thoracic kyphosis narrow the thoracic outlet by reducing the costoclavicular space. This is the primary modifiable contributor to neurogenic TOS and the primary target of physiotherapy. Desk workers, musicians, athletes in overhead sports, and anyone with chronic postural loading of the anterior chest are predisposed.
- Muscular factors — tight scalene muscles (anterior and middle scalene define the borders of the interscalene triangle through which the brachial plexus passes), tight pectoralis minor and tight subclavius can all directly compress neurovascular structures or narrow the spaces through which they travel.
- Anatomical variants — cervical ribs (extra ribs arising from C7), fibromuscular bands, and other structural anomalies narrow the thoracic outlet from birth and predispose to TOS with less postural provocation than in people with normal anatomy.
- Previous trauma — clavicle fractures, first rib fractures and their callus formation can directly reduce the costoclavicular space.
What are the symptoms?
TOS can cause pain in the shoulders and neck, heaviness, and numbness down the arm into the fingers. Symptoms are typically worse when the arm is elevated. Overhead positions — reaching into a cupboard, blow-drying hair, swimming — are classically aggravating because elevation of the arm rotates the clavicle and further narrows the costoclavicular space. Carrying a heavy bag on the affected shoulder, prolonged typing with arms forward, and sustained neck positions that load the scalenes are also common aggravating activities.
The combination of positional aggravation with overhead activities and the ulnar hand distribution is the clinical pattern most useful for distinguishing neurogenic TOS from cervical radiculopathy — which is typically more aggravated by neck movement than arm position.
How is it diagnosed?
Diagnosis involves clinical examination including specific tests like the Adson's manoeuvre to assess nerve or vascular compression, imaging such as X-rays or MRIs to visualise anatomical structures and potential anomalies such as cervical ribs, nerve conduction studies to evaluate nerve function, and vascular tests such as Doppler ultrasound or angiography to examine blood flow.
Provocative clinical tests — including the Elevated Arm Stress Test (EAST or Roos test), the upper limb tension test, the costoclavicular test and Adson's test — reproduce symptoms by stressing the relevant neurovascular structures. No single test has high sensitivity and specificity, and the clinical diagnosis of TOS relies on pattern recognition across the history, examination and test findings. Nerve conduction studies are frequently normal in neurogenic TOS — the compression is often positional and intermittent rather than producing the sustained axonal damage that NCS detects. MRI of the thoracic outlet with provocative positioning can demonstrate compression directly.
How can physiotherapy help?
Physiotherapy is the primary and most effective treatment for neurogenic TOS in the majority of cases. The physiotherapy approach addresses the postural and muscular contributors that are reducing the thoracic outlet dimensions.
Postural correction is the foundation — specifically addressing the forward head posture, protracted scapulae and thoracic kyphosis that narrow the costoclavicular and interscalene spaces. Thoracic extension mobility, scapular retraction and depression strengthening, and deep cervical flexor retraining are the primary interventions. Clinical Pilates is an excellent environment for this work — combining thoracic extension, scapular control and body awareness training in positions that can be modified to avoid provocative arm elevation in the early phases.
Scalene and pectoralis minor stretching directly reduces the muscular compression on the brachial plexus and subclavian vessels. Scalene stretching requires care — overly aggressive stretching can temporarily worsen symptoms and must be introduced gradually.
Neural mobilisation — gentle brachial plexus gliding exercises — reduces the mechanosensitivity of the compressed nerves and improves their capacity to glide freely through the thoracic outlet during arm movement.
Real time ultrasound assists in identifying and retraining the deep cervical and scapular muscles whose dysfunction contributes to thoracic outlet narrowing. Dry needling of the scalenes, pectoralis minor and subclavius provides symptomatic relief and reduces the muscle tension that is compressing the neurovascular bundle.
Ergonomic assessment and modification — workstation height, keyboard position, monitor placement, and sleeping position — addresses the environmental contributors that perpetuate the postural loading pattern.
For vascular TOS or TOS with a significant anatomical contributor (cervical rib, fibromuscular band) that has not responded to physiotherapy, surgical referral is appropriate. First rib resection and scalenectomy are the most common surgical procedures.
Our physiotherapists Yulia Khasyanova and Mauricio Bara both have experience in complex upper limb and nerve conditions and are members of the Australian Physiotherapy Association.
To book or find out more, call us on 07 3706 3407 or book online below. We see patients from across Brisbane's southside including Tarragindi, Coorparoo, Holland Park, Greenslopes and Mt Gravatt.
