A common, painful defect of the wrist and hand. It is caused by pressure on the middle nerve in the carpal tunnel. The syndrome is seen more often in women, especially in pregnant and in menopausal women. Symptoms may result from a blow, swelling, a tumor, rheumatoid arthritis, or a small carpal tunnel that squeezes the nerve. Pain may be infrequent or constant and is often most intense at night.