How is Thoracic Outlet Syndrome diagnosed?

Diagnosis of Thoracic Outlet Syndrome

Thoracic Outlet Syndrome (TOS) is a condition that occurs when the nerves or blood vessels in the thoracic outlet, a narrow space between the collarbone and first rib, become compressed. This compression can lead to various symptoms, including pain, numbness, and weakness in the neck, shoulder, arm, and hand. Diagnosing TOS can be challenging as its symptoms can mimic other conditions, but there are several methods that healthcare professionals use to determine if a patient has this condition.

Medical History and Physical Examination

The first step in diagnosing TOS is a thorough medical history and physical examination. The healthcare provider will ask the patient about their symptoms, when they started, and any activities or positions that worsen or alleviate the symptoms. They will also inquire about any previous injuries or medical conditions that may contribute to the development of TOS. During the physical examination, the healthcare provider will assess the patient's range of motion, strength, and sensation in the affected area. They may also perform specific maneuvers to reproduce the symptoms and evaluate the patient's response.

Imaging Tests

Imaging tests are often used to confirm the diagnosis of TOS and rule out other conditions. The most common imaging techniques used include:

• X-rays: These can help identify any bony abnormalities, such as an extra rib or an abnormal position of the collarbone or first rib.


• Magnetic Resonance Imaging (MRI): This provides detailed images of the soft tissues, such as muscles, ligaments, and blood vessels, allowing the healthcare provider to identify any abnormalities or compression.


• Computed Tomography (CT) Scan: This imaging technique combines X-rays with computer technology to create cross-sectional images of the body. It can help visualize the structures in the thoracic outlet and detect any abnormalities.


• Ultrasound: This non-invasive test uses sound waves to create images of the blood vessels and can help identify any blockages or abnormalities.

Nerve Conduction Studies and Electromyography

In some cases, nerve conduction studies (NCS) and electromyography (EMG) may be performed to assess the function of the nerves and muscles in the affected area. NCS measures the speed and strength of electrical signals as they travel along the nerves, while EMG evaluates the electrical activity of the muscles. These tests can help determine if there is any nerve damage or dysfunction contributing to the symptoms.

Vascular Studies

If vascular compression is suspected, additional tests may be conducted to evaluate the blood flow in the affected area. These tests may include:

• Doppler Ultrasound: This test uses sound waves to assess blood flow and detect any blockages or abnormalities in the blood vessels.


• Angiography: This invasive procedure involves injecting a contrast dye into the blood vessels and taking X-ray images to visualize the blood flow and identify any obstructions.

Other Diagnostic Techniques

In some cases, other diagnostic techniques may be used to further evaluate the condition. These may include:

• Provocative Tests: These involve specific maneuvers or positions that reproduce the symptoms, helping to confirm the diagnosis.


• Injection Tests: Local anesthetic injections may be administered to the affected area to temporarily relieve symptoms, which can help confirm the diagnosis.

It is important to note that the diagnosis of Thoracic Outlet Syndrome often requires a multidisciplinary approach involving healthcare providers from various specialties, such as orthopedics, neurology, and vascular medicine. The combination of medical history, physical examination, imaging tests, and other diagnostic techniques helps healthcare professionals accurately diagnose TOS and develop an appropriate treatment plan.