What are the symptoms of Thoracic Outlet Syndrome (TOS)?

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Last updated: February 28, 2025View editorial policy

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From the Guidelines

Thoracic outlet syndrome (TOS) typically presents with symptoms such as pain, numbness, and tingling in the neck, shoulder, arm, or hand, particularly along the pinky finger and inner forearm, as well as weakness in the hand and arm muscles, and worsening symptoms when raising the arms overhead or carrying heavy objects. The symptoms of TOS can vary depending on which structures are compressed in the thoracic outlet, including the brachial plexus, subclavian artery, and/or subclavian vein 1. Common symptoms include:

  • Pain, numbness, and tingling in the neck, shoulder, arm, or hand, particularly along the pinky finger and inner forearm (ulnar nerve distribution)
  • Weakness in the hand and arm muscles, with difficulty gripping objects or performing fine motor tasks
  • Worsening symptoms when raising the arms overhead or carrying heavy objects
  • Swelling, discoloration, or coldness in the affected arm due to vascular compression
  • Headaches at the base of the skull and neck pain
  • Muscle wasting in the hand over time in neurogenic TOS (the most common type)
  • Severe symptoms like blood clots, discoloration, or even gangrene in extreme cases of vascular TOS. These symptoms typically develop gradually but can be provoked by certain activities or positions that further compress the neurovascular structures in the thoracic outlet between the collarbone, first rib, and surrounding muscles 1. The costoclavicular triangle, interscalene triangle, and pectoralis minor space are the three distinct spaces that can be implicated in TOS, and narrowing of each space results in slightly different presentations due to differing severity of impingement on the transiting neurovascular structures 1.

From the Research

Symptoms of Thoracic Outlet Syndrome (TOS)

The symptoms of TOS can vary depending on the compressed structure(s) and can be classified as neurogenic, arterial, or venous. Some common symptoms include:

  • Arm pain and swelling 2, 3, 4, 5
  • Arm fatigue 2
  • Paresthesias (numbness, tingling) 2, 3, 4
  • Weakness 2, 3, 4
  • Discoloration of the hand 2
  • Upper limb pain 3
  • Numbness or tingling that is exacerbated by shoulder or neck movement 3
  • Pallor (pale skin) 4

Classification of TOS

TOS can be classified into three main forms:

  • Vascular TOS (vasTOS), including arterial TOS (aTOS) and venous TOS (vTOS) 6
  • Neurogenic TOS (nTOS), which is further subdivided into typical (nTOS) and atypical TOS (disTOS) 6
  • A mixed form of nTOS and vasTOS (nvasTOS) 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Thoracic outlet syndrome: a review.

Journal of shoulder and elbow surgery, 2022

Research

Thoracic Outlet Syndrome: A Narrative Review.

Journal of clinical medicine, 2021

Research

Bilateral thoracic outlet syndrome: A rare entity.

JPMA. The Journal of the Pakistan Medical Association, 2020

Research

[Thoracic Outlet Syndrome].

Zentralblatt fur Chirurgie, 2017

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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