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Updated January 02, 2015.

Carpal tunnel syndrome occurs when a nerve is pinched in the wrist. This nerve, called the median nerve, is the connection from the brain down to the finger tips. In patients with carpal tunnel syndrome, the median nerve is pinched as it passes through the wrist. Because of the compression, the nerve does not function properly.

Nerves are structures that relay messages to and from your brain. The nerve sends a message to your muscles when you want to move, and the nerve relays messages to your brain about sensations.


Nerves control specific muscles, and nerves provide sensations for your body. The median nerve (the nerve that is affected in carpal tunnel syndrome) supplies messages to specific muscles of the hand. The median nerve also sends sensory information from most of the palm side of your hand and the thumb, forefinger, middle finger, and half of the ring finger.

The median nerve travels from branches off the spinal cord, down the arm, and into the wrist and hand. In the wrist, the median nerve passes through the carpal tunnel. Carpal comes from the Greek word for 'wrist'-that's what gives the tunnel its name. The carpal tunnel is actually made up of the wrist bones on the bottom, and a tight ligament on the top. The ligament that makes up the top of the carpal tunnel is not flexible, nor are the wrist bones. Coursing through the carpal tunnel is the median nerve, as well as tendons that attach to your fingers.

Signs of Carpal Tunnel Syndrome

Carpal tunnel syndrome is caused when there is pressure in the carpal tunnel that compresses the median nerve, causing the nerve to function improperly.

Because the carpal tunnel is surrounded by bone on one side, and an inflexible ligament on the other, if pressure builds, the nerve has nowhere to go. Simply put, in patients with carpal tunnel syndrome the nerve gets squished.

When carpal tunnel syndrome occurs, the median nerve is pinched, and the normal functions of the nerve are impaired. Problems that can occur include:

• Pain
• Numbness
• Tingling
• Weakness

Carpal Tunnel Risk Factors

Most patients with carpal tunnel syndrome have what is called 'idiopathic' carpal tunnel, which means that there is no clear reason why they developed the condition.  It is well known that carpal tunnel is more common in women than in men, and more common with advancing age.  A number of medical conditions are linked to carpal tunnel syndrome including:

• obesity
• hypothyroidism
• alcoholism
• diabetes
• rheumatoid arthritis
• kidney disease

One of the most common times women are diagnosed with carpal tunnel syndrome is during pregnancy.  In fact, between 20-45% of women are diagnosed with carpal tunnel in the third trimester of pregnancy.  The best treatment for these women are simple measures (like night splints), and the symptoms almost always resolve postpartum.

Treatment of Carpal Tunnel

The typical treatment of carpal tunnel syndrome is to begin with simple steps, and progress to more involved and invasive steps if the simple treatments are ineffective.  There has been a significant amount of research to investigate the best treatments for carpal tunnel syndrome, and the American Academy of Orthopedic Surgeons has published guidelines to help you understand which treatments are effective and which are ineffective.

In patients who don't improve with simple treatments, surgery may become an option.  Surgery is also considered in people who have severe carpal tunnel syndrome, even if simple treatments haven't been attempted.  When surgery is considered, there are options for a traditional open surgical procedure, as well as a minimally invasive endoscopic carpal tunnel release.  As with any surgery, there are possible complications from carpal tunnel release that patients should understand.

<sub>Sources:

Adams, BD. "Endoscopic Carpal Tunnel Release" J. Am. Acad. Ortho. Surg., May 1994; 2: 179 - 184.

Osterman AL, Whitman M, Porta LD. "Nonoperative carpal tunnel syndrome treatment" Hand Clin. 2002 May;18(2):279-89.</sub>