The Adson test is a clinical maneuver used to evaluate for thoracic outlet syndrome (TOS), a condition characterized by compression or irritation of the nerves and blood vessels in the thoracic outlet, which is the space between the collarbone (clavicle) and the first rib. This diagnostic procedure helps healthcare professionals identify potential abnormalities and determine appropriate treatment strategies. In this article, we will delve into the details of the Adson test, its purpose, procedure, and significance in diagnosing thoracic outlet syndrome.
What is Thoracic Outlet Syndrome
Thoracic outlet syndrome refers to a group of disorders that occur when the nerves or blood vessels in the thoracic outlet become compressed, leading to various symptoms in the upper extremities. The thoracic outlet is a narrow passageway bordered by the clavicle, first rib, and the muscles and soft tissues of the neck and shoulder.
Types of Thoracic Outlet Syndrome
There are three main types of thoracic outlet syndrome:
Neurogenic Thoracic Outlet Syndrome (NTOS)
This form of TOS arises from compression or irritation of the brachial plexus, a network of nerves that originate from the neck and supply the upper limbs.
Vascular Thoracic Outlet Syndrome (VTOS)
VTOS occurs when blood vessels, such as the subclavian artery or vein, become compressed or narrowed, leading to reduced blood flow.
Nonspecific or Disputed Thoracic Outlet Syndrome
This type is a catch-all term used when the symptoms of TOS do not fit neatly into the neurogenic or vascular categories, or when the diagnosis is uncertain.
The Purpose of the Adson Test
The Adson test is employed to assess the presence of neurogenic thoracic outlet syndrome. It specifically evaluates for compression or impingement of the brachial plexus nerves as they pass through the thoracic outlet. By performing this test, healthcare professionals can gain insights into the potential causes of a patient’s symptoms and determine if further diagnostic investigations or treatments are necessary.
Procedure of the Adson Test
The Adson test involves the following steps
The patient is instructed to sit upright with their shoulders relaxed.
The examiner locates the patient’s radial pulse (the pulse felt on the wrist) on the affected side.
The patient is then asked to turn their head toward the side being tested and extend their neck backward.
Next, the patient takes a deep breath and holds it.
The examiner palpates the radial pulse and checks for any changes or disappearance of the pulse while maintaining the patient’s head and neck in the extended position.
The patient then relaxes, and the procedure is repeated on the opposite side for comparison.
Interpreting the Results
During the Adson test, if the radial pulse remains normal and unchanged, it suggests that the brachial plexus is not significantly compressed or affected. However, if the pulse diminishes or disappears, it may indicate a positive result, suggesting the presence of neurogenic thoracic outlet syndrome. Further diagnostic tests, such as imaging studies or nerve conduction studies, may be required to confirm the diagnosis.
Limitations and Considerations
While the Adson test can provide valuable information, it is important to note that it is just one part of the diagnostic process for thoracic outlet syndrome. Other factors, such as the patient’s symptoms, medical history, physical examination findings, and additional tests, should be taken into account for a comprehensive evaluation. Furthermore, false-positive and false-negative results can occur, making it essential to interpret the test results in conjunction with the overall clinical picture.
The Adson test is a useful diagnostic tool in evaluating neurogenic thoracic outlet syndrome. By assessing the presence of compression or impingement of the brachial plexus, healthcare professionals can make informed decisions regarding further investigations and treatment options. However, it is crucial to remember that the Adson test should be interpreted in conjunction with other clinical findings to arrive at an accurate diagnosis. A multidisciplinary approach involving healthcare providers from various specialties can help ensure comprehensive care for individuals with thoracic outlet syndrome.