Carpal Tunnel Syndrome

Carpus is derived from the Greek word "karpos" which means "wrist."

Carpal Tunnel Syndrome (CTS) is the name for a group of problems that includes swelling, pain, tingling, and loss of strength in your wrist and hand. It occurs when the median nerve, which runs from the forearm into the hand, becomes compressed or squeezed at the wrist. The carpal tunnel is a space in the wrist surrounded by wrist bones and by a rigid ligament that links the bones together. The median nerve runs through the carpal tunnel, a canal in the wrist that is formed by a series of small bones called the Metacarpals on three sides, and a fibrous sheath called the flexor retinaculum which acts as a pulley for the forearm flexors on the other. There are nine tendons of the hand that also pass through this canal. The median nerve can be compressed in one of a few ways, (1) be by swelling of the contents of the canal, (2) soft tissue swelling in and around the tunnel, (3) by direct pressure from part of a broken or dislocated bone. Nearly half of CTS sufferers have symptoms in both hands.

Carpal Tunnel Syndrome Anatomy

The top of the Carpal tunnel is formed by 8 carpal bones that form 2 rows and (scaphoid, lunate, triquetrum, pisiform) and the distal row of carpal bones (trapezium, trapezoid, capitate, hamate) create the top of the tunnel. These bones are small and glide against each other so that we can move our wrist in different directions. The other side of the carpal tunnel is formed by the flexor retinaculum which forms a retinacular bridge over the carpal tunnel. Its main function is to protect the contained tendon without a significant mechanical action in supporting the transverse carpal arch that acts as a pulley for the wrist flexor ligaments when tension is applied to them by contraction of the forearm flexor muscles.

Inside the Carpal Tunnel there is nine tendons that when pulled flex the fingers of the hand. Flexor digitorum superficialis has 4 tendons that pass through the carpal tunnel and insert on the middle phalanx (middle bone of the finger) of digits 2-5 (all fingers but the thumb). Flexor digitorum profundus has 4 tendons that pass through the carpal tunnel and insert on the middle phalanx (middle bone of the fingers) of digits 2-5 (all fingers but the thumb). Flexor pollicis longus has one tendon that passes through the carpal tunnel and inserts in the distal phalanx (bone at the tip of the thumb). When inflammation occurs in the onset of tendenosis with any of these tendons the median nerve can become compressed then numbness, muscle weakness and tingling can occur to thumb, index finger, middle finger and ring finger.

Causes of Carpal Tunnel

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 singles coming in and out if the hand tissues.

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.

Never use Ultrasound over an area injected with a steroid (ie. cortisone) for at least 30 days.
Never use Ultrasound after surgery until your physician recommends and approves of it.

More Information

www.aidMyCTS.com Aid My CTS with Ultrasound
www.medicinenet.com Carpal Tunnel Syndrome Center
www.answers.com Answers about Carpal Tunnel Syndrome

Carpal Tunnel Syndrome-Type Ailments

Arthritis
Amyloidosis
Atrophy
Carpal Tunnel Syndrome
Diabetes
Hypothyroidism
Leukemia
Multiple Myeloma
Obesity
Pregnancy
Sarcoidosis
Tarsal Tunnel Syndrome

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