Thoracic Outlet Syndrome: A Physiotherapist’s Guide to Understanding and Managing TOS by APA Physiotherapist Bill Kelly

Thoracic Outlet Syndrome (TOS) is a group of conditions caused by compression of neurovascular structures as they travel from the neck to the upper limb. Due to its complex anatomy and symptom overlap with cervical spine and shoulder disorders, TOS is frequently underdiagnosed or misdiagnosed (Hooper et al., 2010). Physiotherapists play a vital role in the conservative management of this condition.

What Is Thoracic Outlet Syndrome?

TOS occurs when the brachial plexus, subclavian artery, or subclavian vein becomes compressed within the thoracic outlet—an anatomical region bordered by the first rib, clavicle, and surrounding musculature (Sanders et al., 2007). Compression most commonly occurs at the interscalene triangle, costoclavicular space, or beneath the pectoralis minor tendon.

Types of Thoracic Outlet Syndrome

Neurogenic TOS (nTOS)

Neurogenic TOS accounts for approximately 70–90% of all TOS cases and involves compression of the brachial plexus (Povlsen et al., 2014). Common symptoms include neck and shoulder pain, paraesthesia in the arm or hand, and upper limb weakness, often exacerbated by overhead activities.

Venous TOS (vTOS)

Venous TOS results from compression of the subclavian vein and presents with upper limb swelling, heaviness, cyanosis, and activity-related discomfort (Sanders et al., 2007).

Arterial TOS (aTOS)

Arterial TOS is the least common but most serious form, involving compression of the subclavian artery. Patients may report cold sensitivity, pallor, reduced pulses, and rapid fatigue during arm elevation (Gillard et al., 2001).

Risk Factors and Contributing Factors

TOS is typically multifactorial, with contributing factors including poor posture, repetitive overhead movements, muscle tightness, and anatomical variations such as cervical ribs (Hooper et al., 2010). Occupational demands and sports requiring sustained arm elevation—such as swimming or manual labour—can increase the risk of developing symptoms.

Clinical Assessment in Physiotherapy

Subjective Examination

A comprehensive history is essential, focusing on symptom behaviour, aggravating postures, neurological or vascular features, and work or sport demands. Symptoms that worsen with sustained postures or overhead activity are commonly reported in neurogenic TOS (Balderman et al., 2019).

Objective Examination

Physiotherapy assessment may include postural analysis, cervical and thoracic spine mobility, shoulder function, muscle length testing, and neural tension testing. Provocative tests such as Roos or Adson’s test may be used, although their diagnostic accuracy is limited and they should not be relied upon in isolation (Gillard et al., 2001).

Physiotherapy Management of Thoracic Outlet Syndrome

Conservative management is recommended as the first-line treatment, particularly for neurogenic TOS, with physiotherapy demonstrating favourable outcomes (Povlsen et al., 2014).

Key Components of Treatment

Postural retraining aims to reduce sustained compression through correction of forward head posture and rounded shoulders, improving thoracic extension and scapular positioning (Hooper et al., 2010).

Mobility interventions focus on thoracic spine movement and soft tissue flexibility, particularly of the scalenes and pectoralis minor, which are commonly implicated in neurovascular compression.

Strengthening and motor control exercises target the deep neck flexors, lower trapezius, and serratus anterior to improve scapular stability and load tolerance (Balderman et al., 2019).

Neural mobilisation techniques may be incorporated cautiously in neurogenic presentations to address neural sensitivity, ensuring exercises remain symptom-guided.

Activity modification and education are critical to reduce symptom provocation and support long-term recovery.

When to Refer

Referral for medical investigation is indicated when vascular symptoms are present, symptoms are progressive, or conservative treatment fails to produce improvement. Vascular TOS in particular often requires specialist assessment and may necessitate surgical intervention (Sanders et al., 2007).

Summary

Thoracic Outlet Syndrome is a complex condition that requires a thorough assessment and individualised management strategy. Physiotherapy plays a central role in conservative care, addressing postural, mobility, and neuromuscular contributors. With appropriate treatment, many individuals experience meaningful symptom improvement and return to normal activity.

References

Balderman J, Abuirqeba A, Eichaker L, et al. (2019). Physical therapy management, surgical treatment, and patient-reported outcomes in thoracic outlet syndrome. Journal of Vascular Surgery, 70(3), 832–841.

Gillard J, Perez-Cousin M, Hachulla E, et al. (2001). Diagnosing thoracic outlet syndrome: contribution of provocative tests, ultrasonography, and helical computed tomography. Joint Bone Spine, 68(5), 416–424.

Hooper TL, Denton J, McGalliard MK, Brismee JM, Sizer PS. (2010). Thoracic outlet syndrome: a controversial clinical condition. Part 1: anatomy, and clinical examination/diagnosis. Journal of Manual & Manipulative Therapy, 18(2), 74–83.

Povlsen B, Hansson T, Povlsen SD. (2014). Treatment for thoracic outlet syndrome. Cochrane Database of Systematic Reviews, (11), CD007218.

Sanders RJ, Hammond SL, Rao NM. (2007). Diagnosis of thoracic outlet syndrome. Journal of Vascular Surgery, 46(3), 601–604.