The condition known as thoracic outlet syndrome is not one thing but the name given to a collection of symptoms, all ascribed to problems with compression of blood vessels or nerves as they pass through the anatomical thoracic outlet. This structure is outlined by the first rib, the collar bone or clavicle and the neck scalene muscles, with the neurological and vascular structures passing through it to reach the axilla and travel into the arm. Diagnosis of these related conditions is difficult and there is little clarity or consensus about them.

People with thoracic outlet syndrome show such wide variation in their symptoms and their signs and there is no clear follow up test to substantiate the diagnosis. This ensures diagnosis of this condition correctly is problematic and unclear. How many people suffer from this syndrome is consequently not certain although higher numbers of female patients present with poor posture and poor development of thoracic and shoulder muscles.

The neurovascular bundle, the rope of nerves and blood vessels, travels from the neck on its way to supply the arm and goes across three small spaces roughly triangular in shape. Any of these small spaces can contribute to compression problems and the spaces are small as the arm is rested by the side, narrowing even further if the arm is moved into certain postures. The positions which increase the tightness of the spaces are used as tests, as testing can indicate which structures are compressing and which being compressed. Physiotherapy and medical testing involves placement of the patient’s arm in a stressful posture and then to ask them to do a repeated action such as clenching and unclenching the fist. This causes an increased demand on the neurological and vascular systems.

The repetitive movement of the shoulder towards the ends of its ranges makes the onset of thoracic outlet syndrome more likely, increasingly so if shoulder abduction (moving the arm out to the side) and outward rotation are involved at end ranges. A common occurrence is for swimmers to complain of pain during their stroke and this should raise the suspicion of thoracic outlet problems. Repetitive shoulder movements towards the end of the available movement make this more likely to occur in many sports or activities. Symptoms may present as neurological difficulties or as problems connected with blood supply to the arm.

Thoracic outlet syndrome presents differently due to whether the compressed structures are the blood vessels, the nerves or both together. The level of pain and disability involved can vary from mild to severe, with symptoms continuous or intermittent. The normal presentation groups are one whose symptoms are not clear or specific, the vascular group and the neurological group. Compression of the main vein or artery in the arm does not occur commonly and perhaps most often in young athletes who perform excessive overhead throwing.

If the arterial flow is disrupted the arm can change colour, there can be pain on muscle use due to their not getting enough blood and an overall pain in the hand and the arm. Mild onset is typical as blood can often get round a blockage, but when the block is large patients attend for medical review independently. Thoracic outlet syndrome from neurological compression involves compression of some of the brachial plexus, a nerve crossroads in the neck which supplies the arms. Nerve compression does not usually occur alone but presents with awkwardness holding a ball or a racket and loss of muscle bulk in the small hand muscles.

Neurological compromise may also cause pins and needles or loss of feeling, with some reports of pain but this tends not to be a major issue. Overhead actions with the arm repetitively tend again to be the aggravating factors. The third group is the contentious one, with a large number of patients who complain of pain in the neck, shoulder blade and arm. Often starting after an accident of some type, this kind of pain is not well understood and there is little medical agreement as to whether this is thoracic outlet syndrome or not.

Jonathan Blood Smyth is the Superintendent of Physiotherapists at an NHS hospital in the South-West of the UK. He writes articles about back pain, neck pain, and injury management. If you are looking for London Physiotherapist visit his website.