Causes of Carpal Tunnel

Gradual, Repetition Based

Most cases of Carpal Tunnel Syndrome are unknown in origin though the condition is signalled by gradually increasing symptoms over time. A common factor in Carpal Tunnel Syndrome is increased hand use or activity. Physiology and family history may be significant factors in a persons susceptibility to the condition.

It is also argued that a common cause of Carpal Tunnel is Repetitive Strain Injury. The almost compulsory long duration use of keyboards when working in an office setting can be aggravate this condition.

Every time you type you are flexing and extending the wrist and fingers requiring the tendons that run inside the carpal tunnel to slide through their protective sheath. The sheath acts as a protective tube to separate the tendon from the surrounding tissues and prevent any adhesions from forming to the tendon itself. It is much like the hand break on a bicycle. When you squeeze the hand break on your bike, the wire travels through the tube and causes the break to engage much like the forearm muscles pull the tendon through the sheath to cause movement in the hand.

Now if the sheath becomes irritated due to the amount of repetitive movement of the tendon through it this is called tendonitis. This irritation is reflected in inflammation that can fill up the carpal tunnel and cause compression on the median nerve. The median nerve sends the signals to all the muscles and receives all the sensations from the tissues and muscles located from the thumb to the middle finger of the hand. You can think of the nerve like your garden hose, when you compress or kink the hose the water cannot flow through freely much like a compressed nerve cannot send or receive the electrical signals coming in and out if the hand tissues.

Single Traumatic Event

It is less common, but single acute traumatic incidents can cause Carpal Tunnel Strain or Carpal Tunnel Syndrome as well. Fractures of the wrist bones (the carpal bones) as well as fractures of the distal radius near the wrist can cause CTS. Acute injuries that do not break bones but stress the wrist excessively (even if for only a very short period of time, such as in a rear end motor vehicle accident while grasping the steering wheel) can cause this problem.

In fact the list of potential causes for CTS is massive, and includes: alcoholism, hemophilia, local tumors such as a lipomata or ganglia, hormonal changes, menopause, pregnancy, rheumatoid arthritis, thyroid imbalance, acromegaly, multiple myeloma, amyloidosis, diabetes mellitus, and local trauma to the wrist as is sometimes seen in motor vehicle accident victims.

What is tenosynovitis and tendonitis?

Tendonitis means inflammation of a tendon.
(It is sometimes spelled as 'tendinitis')

Tenosynovitis means inflammation of the sheath that surrounds a tendon (the sheath is called the synovium). Tenosynovitis can be caused by calcium deposits, repeated strain or trauma, high levels of blood cholesterol, rheumatoid arthritis, gout, or gonorrhea.

These two conditions often occur together.