Thoracic Outlet Syndrome
Basics
Description
- This syndrome consists of a constellation of symptoms that affect the head, neck, shoulders, and upper extremities caused by compression of the neurovascular structures (brachial plexus and subclavian vessels) at the thoracic outlet.
- Three forms of thoracic outlet syndrome (TOS) have been described:
- Neurogenic (nTOS)
- Venous (vTOS)
- Arterial (aTOS)
- Synonym(s): scalenus anticus syndrome; cervical rib syndrome; costoclavicular syndrome; first rib syndrome
Epidemiology
- There are no universal diagnostic criteria to accurately determine epidemiology.
- nTOS
- Approximately 90–95% of all TOS cases (1)
- Predominant in 20- to 50-year-old females
- vTOS
- Approximately 5–10% of all TOS cases (1)
- Predominant in 20- to 35-year-old physically active males
- aTOS
- Approximately 1% of all TOS cases (1)
- No gender preference
Etiology and Pathophysiology
- TOS primarily impacts three anatomic spaces within the thoracic outlet (1):
- Scalene triangle
- Bordered by the anterior scalene, middle scalene, and first rib
- Contains trunks of the brachial plexus and subclavian artery
- Costoclavicular space
- Bordered by the clavicle, first rib, and upper portion of the scapula
- Contains divisions of the brachial plexus, subclavian artery, and subclavian vein
- Subcoracoid space
- Bordered by the pectoralis muscle, 2nd to 4th ribs and coracoid process
- Contains cords of the brachial plexus
- Scalene triangle
- Proposed etiologies include (1):
- Congenital: cervical rib, first rib
- Traumatic: motor vehicle accidents
- Functional: overuse activity of the upper extremity, particularly shoulder abduction/extension
Risk Factors
- Trauma to the shoulder girdle
- Presence of a cervical rib (1% of population)
- Exostosis of clavicle or 1st rib
- Postural abnormalities (e.g., drooping of shoulders, scoliosis)
- Occupational exposure via repetitive activity (e.g., computer users, musicians, overhead athletes, repetitive upper body work)
General Prevention
Consider workplace evaluation for proper occupational ergonomics, including proper posture.
Commonly Associated Conditions
- Paget–von Schrötter syndrome: effort thrombosis of subclavian vein
- Gilliatt-Sumner hand: neurogenic atrophy of abductor pollicis brevis
- Pancoast tumor
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Citation
Domino, Frank J., et al., editors. "Thoracic Outlet Syndrome." 5-Minute Clinical Consult, 33rd ed., Wolters Kluwer, 2025. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117600/all/Thoracic_Outlet_Syndrome.
Thoracic Outlet Syndrome. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2025. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117600/all/Thoracic_Outlet_Syndrome. Accessed October 3, 2024.
Thoracic Outlet Syndrome. (2025). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (33rd ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117600/all/Thoracic_Outlet_Syndrome
Thoracic Outlet Syndrome [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2025. [cited 2024 October 03]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117600/all/Thoracic_Outlet_Syndrome.
* Article titles in AMA citation format should be in sentence-case
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T1 - Thoracic Outlet Syndrome
ID - 117600
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ED - Baldor,Robert A,
ED - Golding,Jeremy,
ED - Stephens,Mark B,
BT - 5-Minute Clinical Consult, Updating
UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/117600/all/Thoracic_Outlet_Syndrome
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