Carpal tunnel syndrome, which is caused by a pinched nerve in the wrist, is a hand and arm condition that causes numbness, tingling and other symptoms. The wrist is surrounded by a band of fibrous tissue that normally functions as a support for the joint. The tight space between the band and the wrist bone is called the carpal tunnel, which is a narrow passageway located on the palm side of the wrist and protects a main nerve to the hand and the nine tendons that bend the fingers. The median nerve passes through the tunnel to receive sensations from the thumb, index and middle fingers.




The three main symptoms are tingling, numbness and pain. They occur in the thumb, the index finger, the middle finger and in one half of the ring finger. However, the tingling, numbness and pain can sometimes extend outside this area. These symptoms can be present in one or both hands, although most cases affect both hands eventually.

Other possible symptoms of CTS include:

  • Discomfort in the hand, forearm or upper arm;
  • A burning, prickling sensation in the hand;
  • Weakness in the hand and a tendency to drop objects;
  • Dry skin, swelling or changes in the skin color of the hand;
  • Hypoaesthesia;
  • Atrophy of the muscles at the base of the thumb.



For most patients, the exact cause of their CTS is unknown. Any condition that exerts pressure on the median nerve at the wrist can cause CTS. Common conditions that can lead to CTS include: tendon inflammation resulting from repetitive work, obesity, pregnancy, a family history of CTS, hypothyroidism, arthritis, diabetes and trauma. 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.



Complications are uncommon, but they may include atrophy and weakness of the muscles at the base of the thumb in the palm of the hand. This can be a permanent complication if not corrected early enough, which can consequently lead to lack of dexterity of the affected fingers.



Risk Factors

A number of factors have been associated with CTS, which include:

  • Anatomic factors, such as: a wrist fracture or dislocation that alters the space within the carpal tunnel;
  • CTS is generally more common in women;
  • Nerve-damaging conditions;
  • Inflammatory conditions;
  • Alterations in the balance of body fluids;
  • Medical conditions, such as menopause, obesity, thyroid disorders and kidney failure;
  • Workplace factors.



There are no proven strategies to prevent CTS, but the patient can minimize stress on the hands and wrists by taking the following precautions:

  • Reduce the force and relax the grip;
  • Take frequent breaks;
  • Watch the form;
  • Improve the posture;
  • Keep the hands warm.