Carpal Tunnel Syndrome is a neuropathy caused by the compression of the median nerve, which travels through the carpal tunnel from the forearm into the hand. It is associated with parasthesiae, pain, numbness, muscle weakness and atrophy in the hand but may also involve similar signs in the arm and forearm.
The carpal tunnel is a structure located on the flexor surface of the wrist, through which a number of important structures pass into the hand from the forearm. These include the four tendons of flexor digitorum superficialis, the four tendons of flexor digitorum profundus, the tendon of flexor pollicis longus and the median nerve.
The median nerve, located in this space, is susceptible to compression by surrounding structures. Distal to the carpal tunnel it supplies the thenar muscles and the first and second lumbricals. Often, in long standing cases of Carpal Tunnel Syndrome, the thenar muscles are particularly weakened and present with a “hollowed” appearance at the thenar eminence as a result of muscle atrophy that has occured. Proximal to the carpal tunnel it also supplies a number of muscles in the forearm and has a sensory branch to the hand which breaks off prior to and thus does not travel through the space.
Many cases of Carpal Tunnel Syndrome are idiopathic but can be associated with a number of other conditions including cases of fluid retention (such as pregnancy), fractures, rheumatoid arthritis, tumours, obesity and others.
A number of treatments are in current usage, each with merits based on the individual patient involved as determined by a health care professional. These may include more invasive interventions such as surgery to relieve pressure placed upon the nerve or injections of corticosteroids to relieve local inflammation. Often patients will use a range of support braces and splints which keep the hand and wrist in place in an attempt relieve pain especially at night where patients can fall asleep in an awkward position. Exercises (including physiotherapy) may also be determined and used in an effort to improve symptoms.