What is carpal tunnel syndrome?

Definition of the carpal tunnel syndrome

You punctually feel pins and needles on the tip of your fingers? Your hands are tingling or seem numbed? You might have the carpal tunnel syndrome . Focus on this musculoskeletal disorder admitted as an occupational disease.


Definition of the carpal tunnel syndrome

The term ‘carpal’ is derived from the Greek Karpos, which means ‘wrist’. This could be surprising given that the symptoms of this condition are specially felt in the hand whereas the problems come from the wrist! More precisely, these problems affect the thumb, forefinger, middle finger and ring finger. This is due to the compression of the median nerve in the carpal tunnel that passes through the wrist. This nerve is the one giving sensitivity to the aforementioned fingers. Then compressed, it doesn’t play its role properly and cause disabling disorders and pain.

Tingling, numbness, sensitivity disorders, strength reduction and decreased grip strength are some symptoms associated with this condition. These symptoms sometimes get mixed up with those of tendinitis , neurological syndrome or trauma .

To better understand this condition, let’s discover more details about the carpal tunnel and the median nerve.


Focus on the carpal tunnel : a limited space

The carpal tunnel is a narrow passage in the wrist. This space is surrounded and preceded by the wrist bones and by a ligament on its anterior side. It is into this inelastic tunnel that pass the median nerve of the hand and the nine flexor tendons of the fingers.

To move a finger, flexor muscles and tendons activate thanks to electrical signals transmitted by the brain. These structures slide in a kind of sheath that is lubricated by synovial fluid .


Focus on the median nerve: numerous roles

The median nerve begins in the arm, continues in the elbow, in the forearm and then in the carpal tunnel . It ends on the tip of the 3 first fingers, on the anterior side of the hand and on the external side of the ring finger.

The median nerve plays several roles:

• It transmits the signals from the brain to produce the wrist and fingers movements;
• It allows sensitivity in the thumb, forefinger, middle finger and part of the ring finger;
• It gives information to the brain: temperature, pain, touching, etc.

If the median nerve is compressed, the transmission of nerve impulse is less effective. As a result, sensations as well as the action of muscles and tendons are impaired.


Dysfunction of the median nerve when compresses in the carpal tunnel

Some movements favour the dysfunctions linked with the carpal tunnel syndrome . For example, extreme angular positions of the wrist highly compress he median nerve; in flexion against the flexor retinaculum, in extension against the carpal bones. This excessive pressure can cause intense pain and impact the functions of the median nerve.

The median nerve can also suffer from chronic compressions. This is often linked with an inflammation of the flexor muscles and tendons of the fingers or of their synovial sheath . As a consequence, it increases the size of tendons, what put pressure on the median nerve.

The carpal tunnel syndrome then involves adopting a neutral posture that keeps the hand aligned with the forearm. Therefore, the space available in the carpal tunnel remains optimal and the compression on the median nerve is limited. Wearing the rigid brace CARP’IMMO™* is used for holding the wrist in this position to reduce pain and allow the joint to rest.

Carpal Tunnel Syndrome, what is it ?

*CARP’IMMO™ is a class I medical device that bears the CE marking under this regulation. Carefully read the instructions before use. Manufacturer: MILLET Innovation. 09/2021

Share this article about