In general, compression of a single nerve anywhere in the body may cause symptoms such as pain, numbness, tingling and weakness. Doctors describe this process as a nerve entrapment syndrome. Neurogenic TOS occurs through the same process, but is much more complex than entrapment of a single peripheral nerve.
In detail, five nerve roots arise from the spinal cord on each side of the neck. After leaving the spinal cord, these nerve roots enter the thoracic outlet. In each thoracic outlet, the nerve roots form a complex branching network, called the brachial plexus. Compression or tension on any part of the brachial plexus may cause symptoms, resulting in neurogenic TOS. Given the complexity of the structure of the brachial plexus, patients can suffer a broad range of symptoms.
Thus, doctors see a complex clinical presentation, since compression may involve any number of the branches of the brachial plexus. Symptoms may include pain, numbness, tingling, coldness and weakness of the affected upper extremity. The neurogenic type of TOS may cause symptoms in one or both arms or hands, as well as the neck, chest, back or shoulders.