Carpal Tunnel Syndrome
(Wrist Problems · Median Nerve Dysfunction)
In this condition factsheet:
The Facts on Carpal Tunnel Syndrome
Carpal tunnel syndrome is due to squeezing of the median nerve as it passes through the wrist to the hand. This nerve is contained in the carpal tunnel, a narrow channel just above the wrist. In carpal tunnel syndrome, the channel starts to shrink, compressing the nerve and causing inflammation. The result is hand pain, numbness, tingling, and sometimes, hand weakness or restricted movement. The ring finger and little finger usually aren’t affected, though the entire hand may be involved in more severe cases.
Carpal tunnel syndrome is one of the most common causes of claims for workers' injury compensation, second only to lower back pain. Women are at three times greater risk of developing carpal tunnel syndrome compared to men. It occurs at any age, but is more common in people over 50 years old.
Causes of Carpal Tunnel Syndrome
The median nerve carries messages between the thumb, index finger, middle finger, and the brain. Pain, touch, and sensation are transmitted to the brain and instructions to move muscles are sent from the brain.
The transverse ligament runs across the inside of the wrist like a watch strap. The carpal tunnel is the space between this and the bones on the outside of the wrist. The tendons, muscles of the fingers, blood vessels, and nerves pass through it. The median nerve lies on top of them on the inside of the wrist. There is just enough room for it between the tendons and the transverse ligament.
Carpal tunnel syndrome results when there is increased pressure on the median nerve and tendons within the carpal tunnel. It is usually a combination of things that causes the increased pressure. Factors that contribute to the development of carpal tunnel syndrome include:
- trauma or injury to the wrist
- certain medical conditions (e.g., rheumatoid arthritis, hypothyroidism or underactive thyroid, diabetes)
- repetitive movements of the hand or wrist
- cysts or tumours
- pregnancy
- frequent use of vibrating hand tools
- having wrists too small for all the ligaments and nerves to fit properly
In many cases, the exact cause cannot be determined.
Symptoms and Complications of Carpal Tunnel Syndrome
Symptoms are caused by the pinched median nerve in the carpal tunnel. People with this condition may experience:
- numbness in two or more fingers
- pain that can extend into the elbows
- tingling or burning sensations in the hand (from thumb to middle fingers), wrist, and forearm
- inability to feel the difference between hot and cold
- difficulty gripping small objects
- fingers feeling swollen
- thumb weakness
Most people first realize something is wrong when they wake up one night feeling that their hand is asleep, yet painful at the same time.
