Thoracic Outlet Syndrome

TOS is compression of the nerves to the arm (the brachial plexus), the main vein of the arm (subclavian vein), or the main artery (subclavian artery) as they pass through the narrow space between the neck, first rib, and collarbone. There are three subtypes. Neurogenic TOS, where the nerves are compressed, accounts for the large majority of cases in published series from Sanders, Illig, and the Society for Vascular Surgery reporting standards. Venous TOS (Paget-Schroetter) and arterial TOS are uncommon but serious and are managed surgically. The three are genuinely different conditions that happen to share a name, and knowing which one you have changes the plan considerably.

A pinched nerve in the neck (cervical radiculopathy) usually gives symptoms along the path of a single nerve root, brought on by tilting the head and pressing down on it (Spurling's test). Neurogenic TOS tends to cause more widespread arm and hand symptoms that are worse with the arm overhead or with carrying, often on the little-finger side of the hand, into the ring and little fingers. On examination, TOS symptoms come on with the arms held up in set positions, such as opening and closing the hands with both arms raised (elevated arm stress test), not with pressure on the neck. The two can coexist, and I assess both when the picture is mixed.

For neurogenic TOS without significant weakness or muscle wasting, rehabilitation is usually the first step, and for many people it is the only one needed. The Cochrane review by Povlsen and colleagues updated in 2014 found limited high-quality comparative evidence but noted that the established intervention pathway remains a trial of physiotherapy first, reserving surgery for those who do not respond. Current non-surgical frameworks describe a graded program built around shoulder blade control, posture, nerve mobility, and breathing pattern. Venous and arterial subtypes are a different conversation and are surgical.

Colour change, coldness, or a swollen, purplish arm after activity can point to a blood vessel problem (venous or arterial TOS) rather than the far more common nerve type. Venous TOS classically shows up as a swollen, heavy, bluish arm, often after repeated overhead work or a bout of hard exertion. Arterial TOS can cause a pale, cold, weak hand, with the pulse disappearing in certain arm positions. Both require prompt vascular assessment. If you are seeing real colour or temperature changes, I want you seen by a vascular physician, not treated in the clinic first.

Stretching and releasing the scalenes can give short-term relief, but on its own it often does not settle the problem. Rehabilitation usually also works on shoulder blade control, breathing, upper back and first rib mobility, and gradually loading the shoulder girdle, although the best program has not been firmly established. Non-surgical frameworks describe this as retraining the whole shoulder and neck region, not just freeing one muscle.

Nerve gliding (neural mobilisation) has a role, but the dose needs care when TOS is easily irritated. Vigorous flossing of the median or ulnar nerve early on often flares symptoms. I usually start with gentle, small movements that slide the nerve without stretching it fully (sliders), and add the more demanding stretching versions (tensioners) only once symptoms are settling and shoulder blade control is improving. Done well, it is useful. Done aggressively, it often backfires.

Published guidance, including non-surgical frameworks and most vascular surgery consensus statements, suggests a minimum of two to three months of consistent physiotherapy before concluding that non-surgical care has not worked. Realistically, meaningful improvement often takes three to six months. A few sessions may be too short to judge the overall plan, but a lack of progress is a reason to reassess the diagnosis, the exercise dose and any practical barriers.

For neurogenic TOS, surgery (usually removal of the first rib and release of the scalene muscles) is usually considered after a proper trial of rehabilitation, often three to six months, has not helped enough, with supporting test results where relevant and a surgeon experienced in TOS. Significant or worsening weakness or muscle wasting is an exception that can bring a surgical opinion forward (INTOS consensus, 2024). The Society for Vascular Surgery reporting standards (Illig and colleagues, 2016) set out how candidates are evaluated. For venous or arterial TOS, surgery is often the main treatment and happens much sooner.