What is carpal tunnel syndrome?

Carpus is a word derived from the Greek word karpos, which means "wrist." The wrist is surrounded by a band of fibrous tissue that normally functions as a support for the joint. The tight space between this fibrous band and the wrist bone is called the carpal tunnel. The median nerve passes through the carpal tunnel to receive sensations from the thumb, index, and middle fingers of the hand. Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index, and the middle fingers -- a condition known as "carpal tunnel syndrome."

What is tarsal tunnel syndrome?

Anatomy similar to that of the wrist and hand exists in the ankle and foot. Tarsal is a word derived from the Latin word for "ankle." When the sensory nerve that passes through the tarsal tunnel is irritated by pressure in the tunnel, numbness and tingling of the foot and toes can be felt. This condition is referred to as "tarsal tunnel syndrome." Tarsal tunnel syndrome is analogous to, but far less common, than carpal tunnel syndrome. It is treated similarly.

What conditions and diseases cause carpal tunnel syndrome?

For most patients, the cause of their carpal tunnel syndrome is unknown. Any condition that exerts pressure on the median nerve at the wrist can cause carpal tunnel syndrome. Common conditions that can lead to carpal tunnel syndrome include obesity, pregnancy, hypothyroidism, arthritis, diabetes, and trauma. Tendon inflammation resulting from repetitive work, such as uninterrupted typing, can also cause carpal tunnel symptoms. Carpal tunnel syndrome from repetitive maneuvers has been referred to as one of the repetitive stress injuries. Some rare diseases can cause deposition of abnormal substances in and around the carpal tunnel, leading to nerve irritation. These diseases include amyloidosis, sarcoidosis, multiple myeloma, and leukemia.

What are carpal tunnel syndrome symptoms?

People with carpal tunnel syndrome initially feel numbness and tingling of the hand in the distribution of the median nerve (the thumb, index, middle, and part of the fourth fingers). These sensations are often more pronounced at night and can awaken people from sleep. The reason symptoms are worse at night may be related to the flexed-wrist sleeping position and/or fluid accumulating around the wrist and hand while lying flat. Carpal tunnel syndrome may be a temporary condition that completely resolves or it can persist and progress.