Carpal tunnel syndrome occurs when a combination of health conditions and activities
puts pressure on the
median nerve as it passes through the
carpal tunnel in your wrist. This pressure leads to
tingling, numbness, pain, and/or weakness in parts of your hand and, sometimes,
up into your arm. Anything that decreases the amount of space in the carpal
tunnel, increases the amount of tissue in the tunnel, or increases the
sensitivity of the median nerve can lead to carpal tunnel syndrome.
Things that help cause carpal tunnel syndrome include:
- Conditions or illnesses that can cause or
contribute to arm pain or swelling in the joints and soft tissues in the arm,
or to reduced blood flow to the hands. These conditions and illnesses include
- Repeated hand and wrist movements that cause the membranes surrounding the tendons (tendon
sheaths) to swell (tenosynovitis).
- Buildup of fluid (edema) in the
carpal tunnel that can occur from pregnancy or such conditions as rheumatoid
arthritis or diabetes.
- Broken wrist bones, dislocated bones, new
bone growth from healing bones, or bone spurs. These can take up space in the
carpal tunnel and put more pressure on the median nerve.
- Tumors and
other growths (such as
ganglions). These uncommon causes of carpal tunnel
syndrome are usually benign.
- Normal wear and tear of the tissues in the hand and wrist caused
by aging and repeated movements of the hand or wrist.
which may contribute to carpal tunnel syndrome by affecting the blood flow to
the median nerve.
Carpal tunnel syndrome is a common work-related injury.
Work that requires forceful or repetitive hand movements, hand-arm vibration,
or working for long periods in the same or in awkward positions—especially when
combined with other health conditions—may cause carpal tunnel syndrome.
In some cases the cause of carpal tunnel
syndrome cannot be determined.