Thoracic Outlet syndrome: information

Thoracic outlet syndrome is a group of conditions characterised by compression or irritation of the brachial plexus and blood vessels (subclavian artery and vein) as they travel from the neck into the upper limb.

The passage of this neurovascular bundle can be compromised by any soft tissue or bony enlargement which reduces the small space within the thoracic outlet located between the collar bone and the first rib. This can be due to:-

• an enlargement of the scalene muscles ( Anterior Scalene syndrome) in the interscalene triangle
•  the presence of a rib in the lower part of the neck (Cervical Rib syndrome)

• poor posture reducing the space of the costoclavicular triangle (costoclavicular syndrome)
• Tightness of the Pectoralis Minor in the subcoracoid space beneath the coracoid process (Pectoralis Minor Syndrome)

The resultant compression can produce an array of symptoms dependant on the extent and location of the compression. It has been suggested that Thoracic Outlet Syndrome can be subdivided into neurogenic, venous and arterial symptoms however, the most common subtype is neurogenic accounting for 95% of cases1(Chang 2010)

The clinic presentation of neurogenic thoracic outlet syndrome are similar to cervical nerve root irritation (C8-T1 more frequently reported than C5-7) and as such symptoms which may be reported include:

• pins and needles in a specific dermatomal distribution. For the C8-T1 nerve root, changes in sensation are frequently felt in the ulnar nerve distribution which is located on the inside of the forearm and hand . This symptom is often worse at night and often is noted in the whole hand with the severity of symptoms being greater in the forth and fifth digits

• Infrequently, weakness and wasting may be observed in the small muscles of the hand and in the finger flexors leading to a reduced grip strength
• 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
• These symptoms may get worse by carrying heavy weights, using ruck sacs or having the arms above the head

With compression of the subclavian artery and vein, vascular symptoms may also be observed such as :

• Swelling or puffiness in the arm or hand
• Bluish discoloration of the hand (cyanosis)
• Hand Coldness and possible cold intolerance
• Feeling of heaviness in the arm or hand
• Deep, boring toothache-like pain in the neck and shoulder region which seems to increase at night
• Easily fatigued arms and hands
• Prominent veins in the hand

Treatment options for Thoracic Outlet syndrome

The diagnosis of this complaint frequently involves a battery of orthopaedic tests as well as imaging studies dependent on individual presentation

After a diagnosis is made by your health care professional, often a conservative line of treatment is initially the first course of action. This frequently involves stretching of the involved muscles (pectoralis minor, scalenes), soft tissue work, nerve mobilisation exercises, mobilisation of the neck and mid back and postural exercise prescription. In some instances surgery is a treatment option.

 1 Andrew K Chang, MD, Associate Professor, Department of Emergency Medicine, Albert Einstein College of Medicine, Montefiore Medical Center
J Stephen Bohan, MD, FACP, FACEP, Director, Observation Medicine, Department of Emergency Medicine, Clinical Director, Harvard Medical School, Brigham and Women's Hospital

Updated: Jan 25, 2010