When pain or tingling occurs in the wrist and hand, people often assume it’s caused by carpal tunnel syndrome. This common condition is familiar to many.

But since carpal tunnel syndrome is not the only cause of hand and wrist pain, it is important to understand what causes carpal tunnel syndrome, who is at risk, and how it can be treated.

See Is My Hand and Wrist Pain Caused by Carpal Tunnel Syndrome or Something Else?

Anatomy of the Carpal Tunnel

The carpal tunnel is literally that: a tunnel. It is a narrow passageway running from the base of the hand’s palm to just above the wrist. The “walls” of the carpal tunnel are formed by wrist and hand bones, and “the roof” is a ligament that runs lengthwise across the wrist known as the transverse carpal ligament.

See Guide to Wrist Anatomy

Running through the carpal tunnel are several tendons that control the movement of the fingers, plus the median nerve. The median nerve sits above the tendons, closest to the transverse carpal ligament.

See Soft Tissues of the Wrist

The median nerve starts around the shoulder in a cluster of nerve roots and branches known as the brachial plexus. It then passes into the bottom of the upper arm, inside the elbow and forearm, through the carpal tunnel, and finally into the thumb, the index finger, the middle finger, and the side of the ring finger adjacent to the middle finger.


How Carpal Tunnel Syndrome Occurs

Because it contains multiple tendons and the median nerve, the carpal tunnel is already a fairly crowded structure. When inflammation in the tendons occur, it compresses the median nerve, causing symptoms like pain, tingling, and numbness to travel down the nerve path.

See Carpal Tunnel Syndrome vs. Soft Tissue Inflammation

Symptoms can occur on either side of the carpal tunnel:

  • Below the carpal tunnel, people typically experience numbness, tingling, and pain in the thumb, index, and middle fingers. This is the most common sign of carpal tunnel syndrome.
  • Above the carpal tunnel, shooting pains can affect the wrist and inner forearm.

It’s possible for both to occur at once, with more consistent pain and tingling in the fingers and occasional shooting pains in the forearm.

People who experience pain and tingling in the thumb, index and middle fingers should make an appointment to see their physician and receive an accurate diagnosis, so treatment can begin. If untreated, injury to the nerve may progress and result in permanent numbness and weakness of the hand.

See 6 Myths and Truths About Carpal Tunnel Syndrome

Dr. Ethan Rand is a physiatrist specializing in spine and sports injuries at Kaiser Permanente, Los Angeles Medical Center. He previously practiced in the Department of Rehabilitation Medicine at Weill Cornell Medicine in New York City, where he also served as an Assistant Professor.