What should you know about subclavian artery thoracic outlet syndrome?

The thoracic outlet is a narrow passage between the neck, first rib, and shoulder region. Muscles, ribs, posture, trauma, or an anatomical variation can narrow this space. Arterial compression may cause a cool or pale hand, colour change, fatigue with arm use, or symptoms that appear when the arm is raised. Arm numbness and tingling or hand numbness can also occur, although nerve or vein compression may be responsible instead. A vascular and neurological examination helps separate these patterns.

Arrange a medical assessment rather than relying on posture exercises alone, especially if one hand is colder or changes colour. The clinician may compare pulses and blood pressure between arms and decide whether vascular imaging or specialist review is needed. If compression is mild and no urgent blood-flow problem is found, physiotherapy may address shoulder control, breathing mechanics, and muscle balance. Postural correction therapy should be personalised; forceful stretching or repeated overhead activity can aggravate symptoms in some people.

Seek emergency care for sudden severe arm pain, a cold or pale or blue hand, rapidly increasing swelling, new weakness, loss of pulse, or numbness that does not settle. These changes may signal a serious circulation problem and should not wait for a routine physiotherapy appointment.

Do my signs suggest arterial, nerve, or venous compression? Are the pulses and blood flow equal in both arms? Do I need vascular imaging? Which positions or exercises should I avoid while this is assessed?