Thoracic Outlet Syndrome

[Physiobase]

Firstly here's an overview of TOS gained from various websites. This should give you a starting point for a more specific assessment of the causative factors, before deciding on a treatment approach.

Thoracic outlet syndrome is actually a collection of syndromes brought about by abnormal compression/pressure on the nerves and vessels in the thoracic outlet area. This is usually caused by bony, ligamentous or muscular obstacles between the cervical spine and the lower border of the axilla. The specific structures compressed are usually the nerves of the branchial plexus and occasionally the subclavian artery or subclavian vein.

Vascular symptoms include:

• Swelling or puffiness in the arm or hand
• Bluish discoloration of the hand
• Feeling of heaviness in the arm or hand
• Pulsating lump above the clavicle
• Deep, boring toothache-like pain in the neck and shoulder region which seems to increase at night
• Easily fatigued arms and hands
• Superficial vein distention in the hand

Neurological symptoms include:

• Parasthesia along the inside forearm and the palm (C8, T1 dermatome)
• Muscle weakness and atrophy of the gripping muscles (long finger flexors) and small muscles of the hand (thenar and intrinsics)
• Difficulty with fine motor tasks of the hand
• Cramps of the muscles on the inner forearm (long finger flexors)
• Pain in the arm and hand
• Tingling and numbness in the neck, shoulder region, arm and hand

Compression occurs when the size and shape of the thoracic outlet is altered. The outlet can be altered by exercise, trauma, pregnancy, a congenital anomaly, an exostosis, postural weakness or changes.

Depending on the exact site of injury and the injury component of the neurovascular bundle, three distinct syndromes or a combination thereof may be encountered. One, neurological syndrome - Two, arterial syndrome - Three, venous syndrome. Each will have varying signs and symptoms. For more information have a look at the Thoracic Outlet Syndrome Website.

Below is a list of the component syndromes which comprise thoracic outlet syndrome along with a brief description of each.

Anterior scalene tightness

Compression of the interscalene space between the anterior and middle scalene muscles-probably from nerve root irritation, spondylosis or facet joint inflammation leading to muscle spasm.

Cervical Rib Syndrome

A variation of the Scalenus Anticus Syndrome is the Cervical Rib Syndrome. In this syndrome, it is an osseous anomaly, not muscular hypertrophy, that is responsible for the compression. Cervical ribs are hereditary elongations of the transverse processes of the C7 vertebrae. They may be unilateral or bilateral.

Costoclavicular approximation

Compression in the space between the clavicle, the first rib and the muscular and ligamentous structures in the area-probably from postural deficiencies or carrying heavy objects.

Pectoralis minor tightness

Compression beneath the tendon of the pectoralis minor under the coracoid process-may result from repetitive movements of the arms above the head (shoulder elevation and hyperabduction).