The Thoracic Outlet is a passageway for blood vessels and nerves to access the upper extremity. The vessels and nerves provide supply to the hand and the arm. The thoracic outlet is a space formed by the first rib and the collar bone; any reduction in the space may result in Thoracic Outlet Syndrome (TOS).
Thoracic outlet syndrome is a group of disorders that occur when the thoracic outlet is compressed, therefore compromising the blood vessels or the nerves within this space. These nerves and blood vessels provide supply to the upper extremity, therefore this syndrome would typically produce symptoms within the arm and hand on the affected side. TOS affects approximately 8% of the population.
There are different types of TOS, and they are categorised by the structures affected:
- Neurogenic TOS– the most common type, accounting for 95% of all diagnosed cases of TOS. This type results in compression of the brachial plexus (a bundle of nerves traveling into the arm). The most commonly affected nerves are the lower 2 nerves exiting the neck- C8 and T1.
- Vascular TOS– occurs when there is compression on one or more of the veins (venous TOS) or arteries (arterial TOS).
- Nonspecific-type TOS– this occurs when people complain of chronic pain in the area of the thoracic outlet, worsening with activity, but the exact cause cannot be determined.
The symptoms of TOS can vary according to what type you are suffering from:
What causes TOS?
- Physical trauma
- Anatomical defects such as an extra rib
- Tight musculature (including bodybuilding)
- Repetitive injuries from work or sports-related activities
- Weight gain
Females are 3-4 times more likely to be diagnosed with the condition than men. This is mainly due to anatomical structure and the presence of breast tissue which may put tension on the shoulders and change the thoracic outlet space.
Young adults are diagnosed more frequently between the ages of 20 and 40 years of age.
Treatment for TOS:
Manual therapy can be effective in the treatment of Neurogenic TOS, as the main aim will be to loosen, stretch and strengthen the muscles surrounding the thoracic outlet in order to open the outlet and improve the range of motion of surrounding joints and tissues. You may also learn how make some postural changes, and how to strengthen these muscles at home to improve your prognosis. This overtime, will increase the size of the thoracic outlet, decreasing the pressure exerted on the nerves and the blood vessels.
In severe cases where symptoms are ongoing or if you experience progressive neurological symptoms, surgery is required.