Thoracic Outlet Syndrome

Upper Limb

Overview

Thoracic Outlet Syndrome (TOS) is a complex of symptoms resulting from compression of the neurovascular bundle (brachial plexus and/or subclavian vessels) as it passes through the thoracic outlet. The condition manifests as pain, numbness, weakness, and vascular symptoms in the upper limb and is classified into neurogenic, venous, or arterial subtypes depending on which structures are predominantly compressed. TOS often develops secondary to postural dysfunction, muscle imbalance, or anatomical variations and requires careful differential diagnosis.

Pathophysiology

The thoracic outlet is bounded superiorly by the anterior and middle scalene muscles, anteriorly by the clavicle and first rib, and posteriorly by the trapezius. Compression can occur at three anatomical sites: between the scalene muscles (interscalene space), behind the clavicle and first rib (costoclavicular space), or beneath the pectoralis minor muscle (subcoracoid space). Compression may result from muscle hypertrophy or hypertonicity (particularly scalenes and pectoralis minor), postural dysfunction (forward head posture, rounded shoulders), cervical rib or fibrous bands, clavicular or first rib abnormalities, or trauma (whiplash). Neurogenic TOS (well over 90% of cases) compresses the lower trunk of the brachial plexus (C8–T1), causing ischaemia and inflammation of nerve fibres. Venous TOS results from subclavian vein compression, leading to thrombosis and oedema. Arterial TOS (rare) involves subclavian artery compression, risking aneurysm formation and distal embolisation.

Patient Education

TOS often improves with postural correction, muscle relaxation, and ergonomic modification; maintaining good posture, avoiding overhead activities, and performing regular stretching of the neck and chest muscles are essential for long-term management and prevention of recurrence.

Typical Presentation

Site

Arm and hand (often ulnar distribution C8–T1), neck, shoulder, and anterior chest; symptoms may extend from neck to fingertips

Quality

Aching, heaviness, numbness, tingling, weakness; vascular symptoms include coolness, colour changes (cyanosis or pallor), or swelling in severe cases

Intensity

Variable; may range from mild intermittent paraesthesia to severe disabling pain and weakness; often worse at end of day

Aggravating

Overhead activities, carrying heavy loads, prolonged typing or computer use, poor posture, sleeping with arm overhead, neck rotation/extension, cold exposure (vascular symptoms)

Relieving

Rest, lowering the arm, postural correction, neck and shoulder stretching, heat application, sleeping in neutral position

Associated

Forward head posture, rounded shoulders, muscle tension in neck and shoulder girdle, weakness of intrinsic hand muscles, swelling (particularly in venous TOS), colour changes or coolness of limb, reduced grip strength, fatigue

Orthopaedic Tests

Test descriptions are written with AI assistance from standard clinical texts. Where a test lists Sources, its description has been checked against them; those sources are independent and do not endorse OsteoKit. Accuracy figures and grades (A–D) appear only when checked against the published study; tests without one are marked “No accuracy study”.

Further reading: full test procedures are described in standard clinical examination texts, e.g. Magee & Manske, Orthopedic Physical Assessment (7th ed.), and Cook & Hegedus, Orthopedic Physical Examination Tests: An Evidence-Based Approach (2nd ed.).

Grade B
A+ABCDGood clinical value: meaningfully changes the diagnosis in one direction (LR 5–10 or 0.1–0.2)
best for ruling OUT (screening).

Upper Limb Tension Test (ULTT) – Median Nerve Bias

Procedure

Patient supine. With the shoulder girdle held down, abduct and externally rotate the shoulder, supinate the forearm, extend the wrist and fingers and then the elbow. Add neck side-flexion away from and towards the test side.

Positive Finding

Reproduction of the familiar arm symptoms that changes with neck side-flexion and differs from the other side.

Sensitivity / Specificity

97%/22%

Reference: Wainner RS et al., Spine 2003; PMID 12544957

Interpretation

Shows that the nerves of the arm are irritable, which fits neurogenic thoracic outlet syndrome but also cervical radiculopathy and other nerve problems. It cannot tell them apart; a negative test makes nerve irritation less likely. Note: these figures derive from cervical radiculopathy populations (Wainner 2003); not validated specifically for thoracic outlet syndrome.

Sources

Grade C
A+ABCDModest value: a small but usable shift in probability (LR 2–5 or 0.2–0.5)
modest, supportive value.

Adson Test

Procedure

Patient seated. Find the radial pulse with the arm slightly abducted and extended. Ask the patient to extend the neck, turn the head towards the tested side and take a deep breath and hold it. Feel for any change in the pulse and ask about symptoms.

Positive Finding

The radial pulse weakens or disappears, ideally with reproduction of the familiar arm symptoms.

Sensitivity / Specificity

79%/76%

Reference: Gillard J et al., Joint Bone Spine 2001; PMID 11707008

Interpretation

A change in pulse alone is common in healthy people, so reproduction of the patient's own symptoms matters more. Most thoracic outlet syndrome is neurogenic, where the pulse is normal. Use it within a cluster of provocation tests, not alone.

Sources

Grade D
A+ABCDLimited value: little effect on the diagnosis on its own
limited standalone value.

Hyperabduction Test (Wright Test)

Procedure

Patient seated. Find the radial pulse, then take the arm slowly into full abduction and external rotation. Hold briefly and ask about symptoms.

Positive Finding

The pulse weakens or disappears with reproduction of the familiar arm symptoms.

Sensitivity / Specificity

70%/53%

Reference: Gillard J et al., Joint Bone Spine 2001; PMID 11707008

Interpretation

Tests compression under pectoralis minor and at the costoclavicular space. Loss of pulse in this position is common in healthy people; reproduction of the patient's symptoms is more meaningful.

Further reading

No accuracy study

Roos Test (Elevated Arm Stress Test – EAST)

Procedure

Patient seated. Arms abducted to 90° with shoulders externally rotated and elbows bent to 90° (hands-up position). Ask the patient to open and close the hands slowly for up to 3 minutes.

Positive Finding

Reproduction of the familiar arm heaviness, pain or tingling, or being unable to continue for 3 minutes because of those symptoms.

Interpretation

Reproduction of the patient's own symptoms supports thoracic outlet syndrome. Symptoms in this position also occur with carpal tunnel syndrome and cervical radiculopathy, and some healthy people feel fatigue, so use it within a cluster. In 266 people assessed for suspected neurogenic thoracic outlet syndrome (Pesser 2022), how long they could keep up the test barely separated those later confirmed to have it from those who did not (area under the curve 0.62, where 0.5 is chance). The test is also often positive without the condition: in 77% of people with carpal tunnel syndrome and 47% of healthy people (Nord 2008). Neither study reported sensitivity and specificity, so no figure is shown.

Sources

No accuracy study

Costoclavicular Test (Military Brace Test)

Procedure

Patient seated. Find the radial pulse, then ask the patient to pull the shoulders back and down and push the chest out, holding for up to a minute.

Positive Finding

The pulse weakens or disappears with reproduction of the familiar arm symptoms.

Interpretation

Tests narrowing between the clavicle and the first rib. Use it within a cluster of provocation tests; a pulse change alone is not diagnostic.

Sources

Further reading

No accuracy study

Halstead Manoeuvre

Procedure

Patient seated. Find the radial pulse and apply gentle downward traction on the arm while the patient extends the neck and turns the head away from the tested side.

Positive Finding

The pulse weakens or disappears with reproduction of the familiar arm symptoms.

Interpretation

Another positional provocation test for thoracic outlet compression. Use it within a cluster; a pulse change alone is common in healthy people.

Sources

Further reading

⚠ Red Flags

  • •Acute onset with severe swelling, colour change, or coldness suggesting venous or arterial thrombosis requiring urgent vascular imaging
  • •Severe progressive neurological deficit with rapid onset of weakness or paralysis
  • •Signs of spinal cord compression: bilateral symptoms, lower limb involvement, or sphincter changes
  • •Pulsatile mass or bruit suggesting aneurysm formation
  • •Systemic symptoms including fever, weight loss, or night sweats suggesting malignancy or infection
  • •Acute trauma with neurovascular compromise

⚡ Yellow Flags

  • •High levels of psychological distress, anxiety, or catastrophising about symptoms
  • •Significant occupational or functional limitations disproportionate to objective findings
  • •Litigation or compensation claims pending
  • •Multiple previous failed treatments leading to negative recovery expectations and reduced rehabilitation engagement
  • •Chronic pain behaviour with widespread symptoms beyond typical TOS distribution
  • •Health anxiety or belief that condition is progressive and degenerative

Osteopathic Techniques

Exercise-based rehab is first-line. One small trial found osteopathic treatment added to physiotherapy reduced pain.

Safety: Arm swelling, colour change, or a cold, pale hand suggest vascular thoracic outlet syndrome: refer urgently, do not treat.

Safety: Before any neck technique, screen for blood-vessel problems in the neck. If there are signs of myelopathy (see Red Flags), do not treat the neck manually: refer.

Region

Scalenes (anterior and middle)

Technique

Soft tissue, scalenes
Grade D
Low evidence: expert consensus or could not be verified against literature
No trial of this technique alone. One small trial tested a mixed osteopathic package.

Rationale

Reduces tension in the scalenes, which can narrow the space the brachial plexus passes through.

How it's done, cautions & evidence

How it's done

Gentle stretch and soft-tissue work to the scalenes, a main stretching target in thoracic outlet rehabilitation. One described stretch: patient supine, the neck is eased into side-bending while the other hand holds the shoulder down, held about 25 seconds within a comfortable range.

Cautions

Keep pressure light: the brachial plexus and cervical nerve roots pass close to the anterior scalene. One case of acute C5–C6 radiculopathy followed a 3-minute deep massage of the anterior scalene in an underweight patient.

Evidence in Thoracic Outlet Syndrome

No trial has tested scalene soft tissue work on its own in thoracic outlet syndrome. One trial of 40 people found a mixed osteopathic package plus physiotherapy reduced pain more than physiotherapy alone.

Region

Pectoralis minor

Technique

Soft tissue, pectoralis minor
Grade D
Low evidence: expert consensus or could not be verified against literature
No trial of this technique alone. One small trial tested a mixed osteopathic package.

Rationale

Reduces tension in pectoralis minor, which can compress the plexus and vessels below the coracoid.

How it's done, cautions & evidence

How it's done

Stretch and sustained pressure to pectoralis minor (ribs 3–5 to the coracoid). A manual stretch can be given supine or sitting; in one study the supine stretch lengthened the muscle more than the sitting one, and a self-stretch most of all. Ischaemic compression of tender trigger points can come first, and a doorway self-stretch (15–20 second holds) suits home care.

Cautions

Conservative care is for pectoralis minor syndrome without arterial or venous thrombosis: rule those out first.

Evidence in Thoracic Outlet Syndrome

No trial has tested pectoralis minor release on its own in thoracic outlet syndrome. One trial of 40 people found a mixed osteopathic package plus physiotherapy reduced pain more than physiotherapy alone.

Region

Scalenes, upper trapezius and levator scapulae

Technique

Muscle energy, scalenes and upper trapezius
Grade D
Low evidence: expert consensus or could not be verified against literature
No trial of this technique alone. One small trial tested a mixed osteopathic package.

Rationale

Patient-powered lengthening of tight neck and shoulder-girdle muscles. Pairs well with the stretching used in rehab programmes.

How it's done & evidence

How it's done

The muscle is taken to the edge of its available range. The patient makes a light contraction (about 10–20% effort) against an unyielding counterforce for 5–10 seconds, then fully relaxes for 3–5 seconds, and the new range is taken up. Repeat a few times, then re-check.

Evidence in Thoracic Outlet Syndrome

No trial has tested MET to the scalenes on its own in thoracic outlet syndrome. Stretching these muscles is a common part of exercise programmes in the published rehab literature.

Region

Lower cervical spine

Technique

Articulation, cervical
Grade D
Low evidence: expert consensus or could not be verified against literature
No trial of this technique alone. One small trial tested a mixed osteopathic package.

Rationale

Gentle movement of stiff lower cervical segments as part of a wider rehab programme.

How it's done & evidence

How it's done

Rhythmic, low-velocity movement of a restricted cervical segment within its passive range, with no thrust. Usually done with the patient supine and the head supported; the amplitude can vary.

Evidence in Thoracic Outlet Syndrome

No trial has tested cervical articulation on its own in thoracic outlet syndrome. Manual therapy appears in some rehab programmes, but it is poorly described.

Rehabilitation Exercises

Scalene Muscle Stretch (Lateral Neck Flexion)

StretchingBeginner

Pectoralis Minor Doorway Stretch

StretchingBeginner

Upper Trapezius Stretch (Neck Side Flexion with Rotation)

StretchingBeginner

Levator Scapulae Stretch

StretchingBeginner

Postural Reset – Shoulder Blade Retraction and Depression

PosturalBeginner

Scapular Retraction Isometric Hold

StrengtheningBeginner

Lower Trapezius Activation (Prone Y Raise)

StrengtheningIntermediate

Serratus Anterior Activation (Push-Up Plus)

StrengtheningIntermediate

Cervical Spine Active Range of Motion (Flexion, Extension, Lateral Flexion, Rotation)

Range of MotionBeginner

Chin Tucks (Cervical Retraction)

PosturalBeginner

Shoulder Girdle Mobilisation (Scapular Circles and Rolls)

Range of MotionBeginner

Proprioceptive Upper Limb Stabilisation Exercises (Standing Arm Patterns)

BalanceIntermediate

Referral Criteria

  • •Acute onset with signs of vascular compromise (severe swelling, colour changes, coldness) — refer urgently to vascular surgery for imaging and assessment
  • •Progressive neurological deficit with significant weakness or atrophy — refer to neurology for electrodiagnostic testing and exclusion of other neuropathies
  • •Suspected arterial TOS with risk of aneurysm formation — refer urgently to vascular specialist
  • •Failure to improve after 6–8 weeks of conservative management — consider referral to specialist TOS centre for diagnostic imaging (MRI, CTA, or venography) and possible surgical intervention
  • •Suspected cervical myelopathy or spinal cord compression — refer to neurosurgery or spine specialist
  • •History of significant trauma with persistent neurovascular symptoms — refer to hand surgeon or trauma specialist for evaluation
  • •Diagnostic uncertainty or complex presentation — refer to musculoskeletal physician or specialist for comprehensive assessment and diagnostic confirmation