Thoracic Outlet Syndrome: Symptoms, Diagnosis & Treatment
This guide explains the three types, how TOS is diagnosed, how it differs from a pinched neck nerve, and what treatment can realistically do.
What Is Thoracic Outlet Syndrome?
The thoracic outlet is the space between the collarbone, the first rib, and the scalene and pectoralis minor muscles. Nerves (the brachial plexus) and blood vessels (the subclavian vein and artery) pass through it to the arm. TOS happens when one of these is compressed.
There are three types, and they behave very differently:
- Neurogenic (nerve pressure): by far the most common type. Neurogenic thoracic outlet syndrome is the one usually managed with therapy and pain care.
- Venous (vein pressure): less common. It can lead to a blood clot in the arm vein, sometimes after hard, repeated arm use.
- Arterial (artery pressure): the rarest type, often linked to an extra rib. It can damage the artery and reduce blood flow to the hand.
Causes and Risk Factors
- An extra rib in the neck (cervical rib) or an abnormal first rib
- Tight or enlarged scalene or pectoralis minor muscles
- Neck or shoulder injury, such as whiplash or a fall
- Repetitive overhead work or sports
- Drooping shoulder posture
Symptoms by Type
- Neurogenic: neck, shoulder, arm, or hand pain; numbness and tingling, often in the ring and little fingers and inner forearm; hand weakness or clumsiness; symptoms that worsen with the arms overhead or carrying heavy bags.
- Venous: arm swelling, a bluish or dark color, heaviness, and sometimes visible veins over the shoulder or chest.
- Arterial: a cold, pale, or painful hand or fingers, pain with arm use, and, rarely, finger sores.
Thoracic Outlet Syndrome vs Cervical Radiculopathy
Symptoms of cervical radiculopathy (a pinched neck nerve) usually change with neck movement and follow one nerve root. TOS is typically provoked by arm position. MRI of the neck and nerve testing help tell them apart. Ulnar neuropathy at the elbow, carpal tunnel syndrome, shoulder problems, and brachial plexopathy are also considered. For more, see cervicobrachial syndrome vs cervical radiculopathy and cervicobrachial pain.
How TOS Is Diagnosed
There is no single test for the neurogenic type. Doctors combine several findings and rule out look-alike conditions.
- History and physical exam, including tenderness above the collarbone
- Arm-position tests, which support but do not confirm the diagnosis on their own
- Chest or neck X-rays to look for a cervical rib
- Nerve conduction studies and EMG. These are often normal in TOS, but they help rule out a pinched neck nerve or carpal tunnel syndrome.
- Duplex ultrasound, and sometimes CT, MR, or catheter imaging, when a vein or artery may be involved
- A diagnostic scalene muscle injection with numbing medicine. Short-term relief supports the diagnosis and is one of the criteria the Society for Vascular Surgery uses.
Treatment Options by Type
Treatment depends on the type. For the neurogenic type, the goal is less pain and better arm use. Results vary, and high-quality trials of TOS treatments are limited.
Physical Therapy First (Neurogenic Type)
- Physical therapy: scalene and chest stretching, shoulder-blade strengthening, posture work, and nerve gliding exercises.
- Activity changes: limiting long periods with the arms overhead and heavy bags on the shoulder.
- Medications for pain or nerve pain when appropriate.
Therapy is the standard first step, but expectations should be realistic. In one specialty-center study, everyone with neurogenic TOS started with a 6-week therapy trial. About 1 in 4 improved enough to continue therapy alone, and most of the others went on to surgery. Many experts advise a longer trial of about 4 to 6 months before surgery is considered.
Image-Guided Injections
An ultrasound-guided injection of numbing medicine into the scalene or pectoralis minor muscle is mainly a diagnostic test. Relief is usually temporary. Botulinum toxin (Botox) injections into these muscles are an off-label use (not FDA-approved for TOS). In a randomized trial they did not relieve pain better than a placebo injection, so they are considered only in selected cases. Trigger point injections may help nearby muscle knots, but they do not treat the compression itself. Other nerve blocks, such as a brachial plexus block, are not a standard TOS treatment.
Potential injection risks include soreness, bleeding, infection, and temporary arm or hand numbness or weakness.
Venous and Arterial Types
These are vascular problems and are managed by a vascular surgeon. A clot in the arm vein is treated urgently with blood thinners and often clot-dissolving treatment, usually followed by surgery to relieve the compression. Arterial TOS usually needs surgery to relieve the compression and repair the artery.
Dr. Amit Sharma & our minimally invasive pain & spine team.
When Is Surgery Considered?
For the neurogenic type, surgery such as first rib removal (first rib resection) and scalene muscle release may be considered when:
- the diagnosis is well supported by exam, testing, and ruling out other causes,
- symptoms stay disabling after a full course of therapy, or
- hand weakness or muscle wasting is getting worse.
Surgery is done by a vascular or thoracic surgeon. Many people improve after surgery, but some still have symptoms, and risks include nerve or blood vessel injury and a collapsed lung. Venous and arterial types usually need surgical or vascular treatment.
When to Seek Medical Care
Go to the emergency room for sudden arm swelling with a bluish or dark color (a possible clot), or a cold, pale, painful hand or fingers (a possible artery blockage). Call 911 if arm swelling comes with chest pain or shortness of breath, because a clot can travel to the lungs.
Schedule a prompt visit for hand weakness, dropping things, or visible muscle wasting in the hand. Book a routine evaluation if arm numbness or tingling with overhead activity keeps coming back.
Thoracic Outlet Syndrome Care at SpinePain Solutions
At SpinePain Solutions, Amit Sharma, MD, Chief, Division of Pain Medicine, Good Samaritan University Hospital, and our team evaluate arm numbness and pain, sort out TOS from look-alike conditions, and offer image-guided, minimally invasive care at our Bay Shore, Commack, and Farmingdale offices. When a vein or artery problem is suspected, we coordinate vascular care. Call 631-310-0000 to schedule.
Frequently Asked Questions
What are the three types of thoracic outlet syndrome?
Neurogenic (pressure on the brachial plexus nerves), venous (pressure on the subclavian vein), and arterial (pressure on the subclavian artery). Neurogenic is by far the most common. Arterial is the rarest.
Why do my hands go numb when I raise my arms overhead?
Raising the arms can narrow the space between the collarbone, first rib, and neck muscles, squeezing the nerves or blood vessels that pass to the arm. Other causes, such as a pinched neck nerve, are also possible; see why your arm goes numb when you raise it.
How is TOS different from a pinched nerve in the neck?
A pinched neck nerve (cervical radiculopathy) usually worsens with neck movement and follows a single nerve root pattern. TOS symptoms are typically brought on by arm position, especially overhead.
How is TOS different from carpal tunnel syndrome?
Carpal tunnel affects the median nerve at the wrist, causing numbness mainly in the thumb, index, and middle fingers, often at night. TOS symptoms more often involve the ring and little fingers, the inner forearm, and the whole arm.
How is thoracic outlet syndrome diagnosed?
Through history and exam with arm-position tests, X-rays to look for an extra (cervical) rib, nerve tests to rule out other problems, and ultrasound or other vascular imaging when a vein or artery may be involved. A test injection of numbing medicine into a scalene muscle can support the diagnosis.
Can thoracic outlet syndrome improve without surgery?
Many people with the neurogenic type improve with physical therapy, posture changes, and activity changes, though it can take months. Venous and arterial types usually need vascular or surgical treatment.
When is arm swelling or color change an emergency?
Sudden arm swelling with a bluish color can mean a blood clot, and a cold, pale, painful hand can mean an artery problem. Both need emergency care. Call 911 if arm swelling comes with chest pain or shortness of breath.
Dr. Amit Sharma & our minimally invasive pain & spine team.
Medical References
- Illig KA, Donahue D, Duncan A, et al. Reporting standards of the Society for Vascular Surgery for thoracic outlet syndrome. J Vasc Surg. 2016;64(3):e23-e35. doi:10.1016/j.jvs.2016.04.039. PubMed.
- Jones MR, Prabhakar A, Viswanath O, et al. Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment. Pain Ther. 2019;8(1):5-18. doi:10.1007/s40122-019-0124-2. PubMed.
- Povlsen B, Hansson T, Povlsen SD. Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2014;(11):CD007218. doi:10.1002/14651858.CD007218.pub3. PubMed.
- Finlayson HC, O’Connor RJ, Brasher PMA, Travlos A. Botulinum toxin injection for management of thoracic outlet syndrome: a double-blind, randomized, controlled trial. Pain. 2011;152(9):2023-2028. doi:10.1016/j.pain.2011.04.027. PubMed.
- Balderman J, Abuirqeba AA, Eichaker L, et al. Physical therapy management, surgical treatment, and patient-reported outcomes measures in a prospective observational cohort of patients with neurogenic thoracic outlet syndrome. J Vasc Surg. 2019;70(3):832-841. doi:10.1016/j.jvs.2018.12.027. PubMed.
- Kaplan J, Kanwal A. Thoracic Outlet Syndrome. StatPearls. Treasure Island (FL): StatPearls Publishing; 2023. NCBI Bookshelf.
