Overview
Carpal tunnel syndrome occurs when the median nerve, which runs through a narrow passage in the wrist called the carpal tunnel, becomes compressed. This causes tingling, numbness, and pain in the hand and fingers, particularly the thumb, index, middle, and part of the ring finger.
How common is it?
Carpal tunnel syndrome affects around 1 in 10 people at some point. It is more common in women and in people over 50.
Causes and risk factors
The carpal tunnel is a tight space in the wrist through which the median nerve and finger tendons pass. When anything causes swelling or narrowing in this tunnel, the nerve becomes compressed.
Common risk factors
- Pregnancy (fluid retention causes swelling)
- Hypothyroidism
- Diabetes
- Rheumatoid arthritis
- Repetitive wrist movements from work or sport
- Wrist fracture or injury
- Obesity
Symptoms
- Tingling and numbness in the thumb, index, middle, and ring fingers
- Symptoms worse at night and on waking
- Dropping objects or clumsiness
- Pain radiating up the forearm
- Weakness of grip
- Relief by shaking hands (known as flick sign)
- In severe cases, wasting of thumb base muscle
When to see a doctor
See a doctor if tingling is persistent, is affecting sleep, or is causing hand weakness or clumsiness. Early treatment prevents permanent nerve damage.
Diagnosis
Tinel's sign (tapping the wrist triggers tingling) and Phalen's test (holding wrist flexed triggers numbness) support clinical diagnosis. Nerve conduction studies confirm the diagnosis and severity.
Treatments
Night splint
A wrist splint worn at night keeps the wrist in a neutral position, preventing compression during sleep. Often dramatically improves nighttime symptoms.
Steroid injection
Injection into the carpal tunnel reduces inflammation and provides significant relief, often for many months.
Carpal tunnel release surgery
A small incision cuts the ligament forming the roof of the carpal tunnel, permanently relieving pressure. Highly effective and performed as day surgery.
Self-care and lifestyle
- Take regular breaks from repetitive hand or wrist activities
- Ergonomic keyboard and mouse positioning reduce wrist strain
- Treat any underlying conditions such as hypothyroidism or diabetes
- Symptoms in pregnancy usually resolve after delivery
Prevention
Ergonomic workstation setup, regular breaks from repetitive work, and treating underlying conditions reduce risk. There is no guaranteed prevention.