We cannot stop wondering as we learn the marvelous secrets of human body. Humans are considered the most evolved organism. Standing straight and erect is considered as one big evolutionary achievement. This is possible as we have a long spine at the back of our body that supports us and helps us to walk erect. The spine is made of several bones called the vertebrae. The spine is divided into 5 regions – the cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacral vertebrae, and the coccyx. As far this article is concerned, our region of interest is the thoracic region that starts from the collar bone (clavicle) to the first rib bone. This narrow passage (thoracic outlet) from the clavicle to the first rib bone is crowded with muscles, nerves, and blood vessels. If the shoulder muscles present in the chest are not strong enough to hold the collar bone in place, then it might slip from its position and crush the underlying blood vessels and nerves resulting in a condition called as thoracic outlet syndrome (TOS).
More about TOS
TOS does not refer to a single disease; it is an umbrella term that describes pain, numbness, and tingling feeling in the neck, shoulder, and arm. If nerve is compressed, then the patient may feel weakness in the arm, and if blood vessel is compressed, the patient will become sensitive to cold, he/she might turn pale or blue, and the arm might swell and he/she may get tired very soon. There are three categories for TOS:
Neurogenic TOS: Caused by compression of brachial plexus (network of nerves from the spine to the arms, fore-hand, and parts of shoulder girdle
Vascular TOS: Caused by pressing subclavian artery or vein
Non-specific or disputed TOS: Unknown cause
Causes
There are many blood vessels and nerves that pass through the narrow passage between shoulder and collar bone to the arms. Any compression or pressure on these nerves or blood vessels due to slipping of the collar bone can compress the underlying blood vessels and nerves and result in symptoms of TOS. Compression occurs due to change in size and shape of the thoracic outlet. And the change in the outlet can be caused by vigorous exercise, over use of shoulder, injury, pregnancy (as joint loosens during pregnancy), pressure on shoulder joint due to obesity, wrong posture, or may be due to congenital anomalies (defects from birth). People having long neck and drooping shoulders can also develop TOS due to extra pressure on the blood vessel and nerve. TOS is more common in women than men.
Symptoms
TOS may manifest as pain, numbness, and tingling in the ring finger and forearm, and regions of neck and shoulder. The pain worsens, if something heavy is carried. It may lead to a weakened grip. The arms may become cold and turn blue due to poor circulation. There may be no pulse in the affected arm due to compression of blood vessels. The arm may become swollen. In some people, there may be blood clot near the collar bone due to blood vessel compression. Throbbing lump near collar bone may be felt, due to blood vessel compression. There may be visible chest veins. The person may have difficulty with overhead activities.
Diagnosis
Diagnosing TOS is not an easy task unlike many other diseases such as – rotor cuff injury, fibromyalgia, multiple sclerosis, cervical disc disorder, complex regional pain syndrome, and tumor of the syrinx or spinal cord; all exhibit symptoms similar to TOS. There are several tests to diagnose TOS, which starts with medical history and physical examination. Before doing any specific diagnosis for TOS, the physician would like to know about the signs and symptoms from the patient. Then, a simple physical examination will be conducted to check the pain, swelling, color change, and limited motion of the shoulder. During physical examination, the physician will perform a test that provokes symptoms of TOS, which is used to study the cause of the symptoms. If the blood pressure and the pulse rate in the affected arm is diminished, or the symptoms start showing after the provocation test, then TOS is confirmed. This test is repeated in the healthy arm also as most of the time it produces false-positive results. An electromyography (EMG) is performed to know the status of the muscle and nerve and their working capability. Nerve conduction velocity (NCV) testing is done to check how the nerve is able to carry impulse to the brain and to other parts of the body. X-ray study helps to know the condition of the thoracic outlet and the bones surrounding it. It also shows any extra cervical rib in the thoracic outlet region. An MRI scan produces computer images of soft tissues of the body. It helps to know the cause and location of compression of the nerve or blood vessel in the thoracic outlet region. CT scan detects any problem in the bone. Ultrasound makes images of the body, using sound waves. It helps to find out any blood clot, narrowing, or blockage in the vessel, and nerve compression. Angiography is similar to X-ray but captures pictures of arteries and veins, helps to detect any blockage or compression of the blood vessels. In a procedure called arteriography or venography, a special dye is injected into the blood stream to make arteries and veins visible. Now X-ray is taken to check for any blockage or damage to blood vessels.
Treatment
Treatment options for TOS depend on the symptoms and the cause of the symptoms. Physical therapy or exercising the shoulder joint will help to strengthen the shoulder muscle and hold the collar bone in position and release the pressure on any nerve or blood vessel. Physical exercise that helps to maintain a straight posture while sitting and standing will help to minimize the pressure on blood vessel and nerves. To ease or minimize pain, the physician might prescribe non-steroidal anti-inflammatory drugs like ibuprofen and aspirin. If blood clot is detected, then the physician will prescribe a blood thinner or thrombolytic medicine to dissolve the clot; this also helps to reduce swelling of the arm. Weight reduction is another best method that avoids pressure on nerves and blood vessels. If work/job is strenuous and involves heavy weight job, then change of work is required. If the above said treatments fail, then surgery is required to remove or release the structure that is compressing the nerve or blood vessel.
Outlook
TOS that is untreated for many years can result in permanent damage to the shoulder movement. Therefore, it is essential that if the patient knows that he is at high risk for TOS, then he/she should practice few precautionary steps. The person should avoid lifting heavy objects, especially on the shoulder; if obese, reducing weight is one best option. The patient should everyday practice physical activities that will help to strengthen the shoulder muscle. Healthy living is the best treatment and preventive option.
