Wrist and hand
Carpal tunnel syndrome
The carpal tunnel is a narrow passage on the palm side of the wrist, bounded by the wrist bones and a thick ligament, through which the median nerve and the finger flexor tendons pass. Carpal tunnel syndrome is the collection of symptoms produced when pressure within that tunnel compresses the median nerve. It is the most common nerve entrapment, and its symptom pattern follows the nerve’s territory: the thumb, index and middle fingers, and half the ring finger.
Symptoms
The distribution and the timing together are characteristic enough to suggest the diagnosis before any test is performed.
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Numbness and tingling in the median distribution
Affecting the thumb, index and middle fingers and the thumb side of the ring finger. The little finger is supplied by a different nerve and is typically spared.
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Waking at night
One of the most characteristic features. People commonly describe shaking or hanging the hand out of bed for relief.
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Symptoms with sustained grip
Driving, holding a phone or a book, and similar sustained positions frequently provoke it.
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Weakness and clumsiness
In more advanced cases, weakness of thumb movement and wasting of the muscle at the base of the thumb. These are later findings and a reason not to delay assessment.
Causes and risk factors
Anything that reduces the space in the tunnel or increases the volume of its contents can contribute.
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Anatomy and repetitive use
A naturally narrow tunnel, and sustained or repetitive forceful wrist use, particularly with vibration.
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Medical conditions
Diabetes, thyroid disease, rheumatoid arthritis and obesity are each associated with increased risk.
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Pregnancy
Fluid retention during pregnancy commonly produces symptoms, which frequently resolve after delivery.
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Injury
Wrist fracture or dislocation can alter the dimensions of the tunnel.
Diagnosis
The main differential is a cervical nerve root problem, which can produce overlapping hand symptoms and is managed entirely differently.
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Examination
Sensory testing in the median distribution, thumb strength, assessment for muscle wasting, and provocative manoeuvres at the wrist.
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Nerve conduction studies and EMG
The confirmatory test. It measures how well the median nerve conducts across the wrist, grades severity, and distinguishes carpal tunnel syndrome from radiculopathy or a more generalised neuropathy.
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Ultrasound
Can show swelling of the nerve at the tunnel and identify space-occupying causes, and is sometimes used alongside electrodiagnostic testing.
Common questions
Why is it worse at night?
Most people sleep with the wrist flexed, which raises pressure inside the tunnel, and fluid distribution when lying down contributes. This is why a night splint is often effective.
Is it caused by typing?
Heavy, forceful and vibrating tool use shows a clearer association than ordinary keyboard work. Computer use is a commonly assumed cause but the evidence for it is weaker than generally believed.
Do I need nerve testing before treatment?
Not always for a trial of splinting, but it is the standard test for confirming the diagnosis, grading severity, and excluding a nerve root problem — and it is usually obtained before surgery.
Will it get better on its own?
Mild symptoms sometimes settle, particularly where a reversible cause such as pregnancy is involved. Persistent numbness, weakness or muscle wasting is unlikely to resolve without treatment.
General reference information, and not advice about your own case. It may not reflect the most recent guidance or what is offered on a given day — call (201) 408-5151 to check.
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