Thoracic outlet syndrome

What it is

The nerves and blood vessels supplying the arm pass through a narrow corridor between the scalene muscles in the neck, over the first rib and under the collarbone, then beneath pectoralis minor. Compression anywhere along that route produces arm symptoms.

The great majority of cases are neurogenic - compression of the brachial plexus - producing numbness, heaviness and fatigue, typically worse with the arms raised. Vascular forms are much rarer and more serious: a swollen, blue, painful arm or a cold, pale one is a vascular emergency rather than a postural problem.

What it feels like

• Aching, heaviness and fatigue in the arm, worse with it raised or held out
• Numbness and tingling, often along the little-finger side of the arm and hand
• Symptoms worse carrying a bag, hanging washing, driving or sleeping with the arm up
• Weakness and dropping things after sustained use
• Sometimes neck and shoulder pain, and a heavy dead feeling overnight

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Tight or overactive scalene muscles

The nerves pass between the scalene muscles in the neck. Shallow upper-chest breathing recruits them as accessory breathing muscles thousands of times a day, keeping them short and tight.

A depressed, forward shoulder girdle

Rounded, drooping shoulders narrow the space between the collarbone and the first rib. This is why posture and scapular strength are central to treatment.

Tight pectoralis minor

The neurovascular bundle passes beneath this muscle. When it is short it compresses the structures with the arm raised, which is why symptoms are position-dependent.

A cervical rib or fibrous band

An extra rib at the base of the neck, or a fibrous band in its place, narrows the space anatomically. It is present in a small percentage of people and is the classic structural cause.

Carrying loads on the shoulder

A heavy bag strap presses directly over the space and pulls the shoulder girdle down. It is one of the most immediate and most correctable aggravators.

Repetitive overhead work

Hairdressing, painting, swimming and throwing all hold the arm in the position that closes the space, repeatedly.

Whiplash and neck trauma

A significant proportion of neurogenic cases follow a neck injury, probably through scalene muscle changes and scarring.

A large bust or a heavy chest

Weight pulling the shoulder girdle down and forward narrows the space in exactly the way the postural cause does.

Poor sleep position

Sleeping with the arm above the head holds the space closed for hours, which is why overnight numbness is so common.

Being misdiagnosed

Neurogenic thoracic outlet syndrome is frequently mistaken for carpal tunnel syndrome, cubital tunnel or a neck nerve root problem. Treating the wrong one is a common reason it persists for years.

Who tends to get it

• Anyone with rounded, drooping shoulders and a forward head
• People doing repetitive overhead work
• Anyone who carries a heavy bag on one shoulder
• Women, in whom it is more commonly diagnosed
• People with a previous whiplash or neck injury

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineNeck Relief & Range

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Arm swelling, discoloration, or coolness suggests vascular TOS - urgent vascular referral, this is not a stretching problem

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Neurogenic thoracic outlet syndrome responds well to a structured programme of postural strengthening, stretching and breathing retraining over three to six months, and conservative treatment is the appropriate first choice for most people. Surgery is reserved for cases that fail it or where a structural cause is clear. The vascular forms are different: a suddenly swollen, blue, painful arm or a cold, pale, pulseless one needs emergency assessment.

Prevalence basis: Vascular and neurosurgical series

Others the same routine covers

These share the Neck Relief & Range routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.