Thoracic outlet syndrome
Between the base of the neck and the armpit there is a short, tight corridor. Through it the nerves of the brachial plexus, the subclavian artery and the…
Prescription review online
A doctor will review your case and issue a prescription if medically appropriate.
Talk to a doctor online
Discuss your symptoms and possible next steps with a doctor online.
On this page
Medicines commonly prescribed for Thoracic outlet syndrome
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: TABLET, 650 mgActive substance: paracetamolManufacturer: Laboratorio Stada S.L.Prescription requiredDosage form: ORAL SOLUTION/SUSPENSION, 600 mgActive substance: ibuprofenManufacturer: Laboratorio Stada S.L.Prescription requiredDosage form: ORAL SOLUTION/SUSPENSION, 100 mg ibuprofen / 5 mlActive substance: ibuprofenManufacturer: Laboratorios Normon S.A.Prescription not required
Between the base of the neck and the armpit there is a short, tight corridor. Through it the nerves of the brachial plexus, the subclavian artery and the subclavian vein leave the chest and travel into the arm. When that corridor narrows further, its contents are squeezed, and the arm starts to go numb, to tire quickly, to swell or to turn cold. That is thoracic outlet syndrome. One name covers three different conditions with very different degrees of urgency: one is treated with exercise over months, the other two need attention the same day. So the first thing worth sorting out is which of the three you have.
Where the space runs out
There are three tight spots along the route, one after another.
- The gap between the anterior and middle scalene muscles in the neck. The nerves and the artery pass through it; the vein does not.
- The slot between the collarbone and the first rib. Everything goes through here — nerves, artery and vein. It is the commonest site of compression, and it explains why symptoms get worse when you raise your arm: the collarbone moves down and back and the slot closes.
- The space beneath the pectoralis minor muscle, nearer the shoulder. Everything arrives here after emerging from under the collarbone.
The corridor can be narrowed by something you were born with or by something acquired. The best known congenital cause is a cervical rib, a short extra rib growing from the seventh neck vertebra. Roughly one person in a hundred has one, and most of them never have a symptom in their lives. There are also fibrous bands, which do not show on an X-ray, and first ribs of unusual shape.
Acquired causes are more numerous: a collarbone fracture that healed out of line, a whiplash injury to the neck, the habit of holding the head forward with the shoulders dropped, a heavy bag always on the same shoulder, large breasts with straps that dig in, and bulky scalene muscles in someone who breathes only with the top of the chest. A group of their own are people who work with their arms up: painters, hairdressers, electricians, fitters, assembly line workers, and also swimmers, volleyball players, throwers and weightlifters.
The neurogenic form: much the commonest
Nine cases in ten are compression of the nerves rather than the vessels. It is usually the lower part of the brachial plexus that suffers, and the picture is fairly recognisable.
- Numbness and pins and needles in the arm, particularly in the little and ring fingers and along the inner edge of the forearm.
- A dull ache in the neck, over the top of the shoulder, in the shoulder blade and down the inner side of the arm.
- The arm tires and weakens quickly, things slip out of the fingers, and holding a mug or a hairbrush becomes hard work.
- All of it is clearly worse with the arms up: drying your hair, hanging out washing, painting a ceiling, reaching a high shelf, holding a handrail on the bus.
- Numbness may wake you at night, especially if you sleep with the arm above your head.
- After a long time the muscles of the hand between thumb and index finger become flatter.
Less often the upper part of the plexus is compressed. Then it is the neck, the side of the head and the front of the chest that hurt, and the numbness runs into the thumb and index finger. On the left, that pain sometimes raises the fear of the heart, and that is worth checking rather than waving away.
The neurogenic form is a nuisance and it gets in the way of work, but it does not put the arm at risk. There is plenty of time for unhurried investigation and for months of work with a physiotherapist.
When it is a matter of hours
The other two forms are far rarer, but they behave quite differently, and they need to be recognised in the first few hours.
The venous form. Over a few hours the whole arm swells, from hand to shoulder, turns bluish or purple, feels heavy and tight, and dilated surface veins appear over the shoulder and chest wall. It often happens to a young, healthy person after hard repetitive arm work or a training session. Behind that picture is a thrombosis of the subclavian vein — a genuine deep vein thrombosis, only in the arm, and it can throw a clot to the lungs. This needs a doctor the same day, not watchful waiting until Monday.
The arterial form. The rarest, and almost always linked to a cervical rib or another bony anomaly. The hand is pale and cold to the touch, the arm fills with pain during exertion and forces you to stop, and the pulse at the wrist is weak or cannot be felt at all. Sometimes small dark spots appear on the fingertips, the trace of tiny clots that have broken away.
Call an ambulance straight away if:
- the arm has suddenly turned white, cold and very painful, and is losing movement and sensation;
- there is sudden breathlessness, chest pain on breathing in, coughing up blood or a blackout — that is how a pulmonary embolism presents.
In Spain, Italy, Portugal, Poland and Ukraine the single European number 112 is in use. A swollen, blue arm without breathlessness does not need an ambulance, but it does need to be seen by a doctor today.
What it gets mistaken for
This diagnosis is hard to make, and people are often treated for two or three other things first. The reason is simple: there is no test and no scan that says "yes, this is it", and there are plenty of look-alikes.
- A cervical disc prolapse. Also neck pain with numbness in the arm. It differs in getting worse when you turn or tilt the head rather than when you raise your arms, and it usually fits the territory of a single nerve root.
- Carpal tunnel syndrome. Numbness in the thumb, index and middle fingers, waking you at night and easing when you shake the hand. Here it is the median nerve at the wrist that suffers, not the plexus.
- Ulnar nerve compression at the elbow. The most treacherous twin: the same fingers, little and ring. The clue is that it worsens with the elbow bent — a long phone call, for instance — rather than with the arm raised.
- Shoulder problems such as a rotator cuff tear or bursitis. There the pain is tied to shoulder movement and to one spot on the shoulder, and there is no numbness.
- Raynaud's phenomenon. The fingers blanch in the cold symmetrically on both hands, which is not what compression of one subclavian artery does.
And one thing that should be said plainly. The lower part of the brachial plexus can be compressed not by a muscle or a rib but by a tumour at the apex of the lung. What raises the suspicion is stubborn shoulder pain that keeps you awake and does not change with the position of the arm, in someone who smokes, especially if a drooping eyelid and a small pupil on the same side, weight loss or a hoarse voice have joined in. It is uncommon, but it is precisely why a chest X-ray is arranged for these complaints instead of sending you straight to a massage therapist.
How it is investigated
It starts with the history and the examination. The doctor asks which arm positions make things worse, looks at your posture and the set of your shoulder blades, compares the girth and colour of the two arms, tests power and sensation, and feels the pulses.
There are provocation manoeuvres: the arms are raised and opened out and you are asked to open and close your hands for three minutes to see whether the symptoms come back. One important detail: the pulse simply disappearing when the arm is raised is not a diagnosis, because it happens in a great many healthy people. What counts is the return of your familiar numbness and pain, not the pulse on its own.
After that it depends. X-rays of the chest and neck look for a cervical rib and for the aftermath of a collarbone fracture. Nerve conduction studies are less about confirming compression of the plexus than about ruling out the carpal and cubital tunnels. An MRI scan of the neck settles the question of a disc prolapse. If a vascular form is suspected, a duplex ultrasound scan of the arm vessels is done, including with the arm raised, and then, if needed, CT or MR angiography.
What helps in the neurogenic form
The backbone of treatment is neither medicine nor surgery but work with a physiotherapist, and it is long work: the first shift usually comes at about six weeks, a clear result at three to six months. Giving up in the second week achieves nothing.
- Strengthening the muscles that draw the shoulder blades down and together — they return the shoulder girdle to a position in which the corridor is wider.
- Stretching the scalene muscles of the neck and the pectoralis minor.
- Retraining the breath to come from the abdomen. Breathing with the top of the chest keeps the first rib lifted and sustains the compression.
- Nerve gliding exercises — gentle, pain-free, with no "stretch it harder".
- Going through the workstation: lower the working height, remove sustained overhead movements, alternate tasks, take breaks.
Everyday details pay off here more than you would expect. A rucksack instead of a bag always on the same shoulder; wide straps and a properly fitted supportive bra if the breasts are large; sleeping without the arm above the head; stopping the long phone calls held against the ear. Painkillers, muscle relaxants and drugs for neuropathic pain are given in short courses, so that the exercises become possible — not instead of them. Botulinum toxin into the scalene muscle is offered in selected cases, but the evidence for it is thin and it should not be counted on as the answer.
When surgery is discussed
In the vascular forms surgery is discussed almost always, and fairly quickly. First the acute situation is dealt with — in thrombosis with anticoagulants, sometimes by dissolving the clot — and then the cause is removed, that is, the first rib or the cervical rib, so that the thrombosis does not come back. In the arterial form the damaged segment of artery often has to be repaired at the same time.
In the neurogenic form the logic is different. Surgery comes up when several months of treatment genuinely carried out have not worked, the picture is clear and the symptoms seriously interfere with life. The first rib is removed and, where necessary, the scalene muscle is divided and fibrous bands are taken out. It is worth knowing in advance that the operation does not help everyone, that complete relief is not the rule, and that the possible complications include injury to the nerves of the plexus, air entering the pleural cavity and damage to the lymphatic duct. It is a sensible step, but not the first one.
Online consultation
A remote appointment does the main job here: sorting the situation by urgency. The doctor will ask what exactly goes numb, which arm positions make it worse, whether the colour, temperature or size of the arm has changed, and will ask you to hold both arms up to the camera and compare them. That is usually enough to tell a quiet neurogenic form, which can be thought about over weeks, from a vascular one that means going to a doctor today.
The second reason people come is to stop spending years being treated for the wrong thing. A remote appointment is a good setting for going through how your picture differs from carpal tunnel syndrome and from a cervical disc, and for drawing up a sensible plan of tests instead of ordering the lot. The third is support through the long months of exercise: adjusting the load, reviewing your workstation from photographs, and deciding when it is time to talk about surgery.
If, however, the arm has swollen and turned blue over a few hours, or has become pale, cold and painful, there is no reason to wait for any appointment — that is a reason to seek help immediately.
This material is for information only and does not replace medical advice.
Consult with a doctor about Thoracic outlet syndrome
Discuss your symptoms and possible next steps with a doctor online.
Online doctors for Thoracic outlet syndrome
Discuss your symptoms and possible next steps for Thoracic outlet syndrome with a doctor online.
