THORACIC OUTLET SYNDROME

I see many people who complain of numbness and weakness in their arm or numbness and tingling going down the arm. Usually I think of a pinched nerve in the neck, or carpal tunnel syndrome. A rare condition that is not uncommonly diagnosed is Thoracic Outlet Syndrome ( TOS ). Yankee pitcher Phil Hughes was also thought to have this recently, although this was later ruled out.

Thoracic Outlet Syndrome is compression of the neuro-vascular structures in the supra-clavicular region of the shoulder. In lay terms, this is the area between the base of the neck and the shoulder -just where a woman's bra strap lies. The actual anatomic Thoracic Outlet is an interval between the clavicle (collarbone) on top and the first rib below. The area is covered by the scalene muscles in the front and back. These muscles extend from the sides of the upper spine in the neck down to the first rib. Passing through the Thoracic Outlet are the subclavian artery and vein and major nerve bundles ( the Brachial Plexus ). These nerves branch off and descend down the arm. It's blood supply is from the artery.

Rarely, people may have an extra rib -a cervical rib - which abnormally comes off of the C7 vertebra. This, along with tight scalene muscles, can compress the vascular and nerve structures and produce numbness when the arm is overhead.

TOS can be congenital or developmental. It can be post traumatic or be associated with a fractured clavicle. It is more common in woman. It can be aggravated by obesity or enlarged breasts. Or, from weak shoulder muscles like the Traps. But, it may occur for unknown reasons.

Patients will complain of numbness and perhaps some subtle finger weakness or loss of dexterity. Frequently symptoms occur at night, perhaps due to overhead positioning of the arms over the pillow. Commonly the 4th and 5th fingers are numb, and this is frequently a tip-off for me.

Pulse alterations with deep breaths ( Adson Test ) or overhead positions are common with TOS and raise suspicions.

Work-up includes neck and shoulder x-rays, and perhaps an MRI, EMG's, or a vascular surgery consult. Differential diagnosis includes a cervical disc herniation; a peripheral nerve compression syndrome(carpal tunnel or ulnar neuropathy) ; or, rarely, a lung tumor.

Thoracic Outlet Syndrome is usually treated conservatively -ergonomic and positional changes , and, physiotherapy to strengthen the Traps and other shoulder muscles. Surgery is rare. The first rib and tight scalene muscle is removed and this will cure the condition. But, most people with this do not require surgery.