Diminished discriminant sensibility can be measured by testing two-point discrimination: the number of millimeters two points of contact need to be separated before you can distinguish them.A person with idiopathic median neuropathy at the carpal tunnel will not have any sensory loss over the thenar eminence (bulge of muscles in the palm of hand and at the base of the thumb). This is because the palmar branch of the median nerve, which innervates that area of the palm, separates from the median nerve and passes over the carpal tunnel.Severe IMNCT is also associated with weakness and atrophy of the muscles at the base of the thumb. People may lose the ability to palmarly abduct the thumb. IMNCT can be detected on examination using one of several maneuvers to provoke paresthesia (a sensation of tingling or "pins and needles" in the median nerve distribution). These so-called provocative signs include:

Phalens maneuver. Performed by fully flexing the wrist, then holding this position and awaiting symptoms. A positive test is one that results in paresthesia in the median nerve distribution within sixty seconds. Tinels sign is performed by lightly tapping the median nerve just proximal to flexor retinaculum to elicit paresthesia. Durkan test, carpal compression test, or applying firm pressure to the palm over the nerve for up to 30 seconds to elicit paresthesia. Hand elevation test The hand elevation test is performed by lifting both hands above the head.
Physician George S. Phalen of the Cleveland Clinic identified the pathology after working with a group of patients in the 1950s and 1960s. TreatmentPaget described two cases of carpal tunnel syndrome. The first was due to an injury where a cord had been wrapped around a mans wrist. The second was due to a distal radial fracture. For the first case, Paget performed an amputation of the hand. For the second case Paget recommended a wrist splint – a treatment that is still in use today. Surgery for this condition initially involved the removal of cervical ribs despite Marie and Foixs suggested treatment. In 1933 Sir James Learmonth outlined a method of decompression of the nerve at the wrist. This procedure appears to have been pioneered by the Canadian surgeons Herbert Galloway and Andrew MacKinnon in 1924 in Winnipeg but was not published. Endoscopic release was described in 1988. See also
Repetitive strain injury
Tarsal tunnel syndrome
Ulnar nerve entrapment

References
External links

Carpal Tunnel Syndrome Fact Sheet (National Institute of Neurological Disorders and Stroke) Archived 2016-03-03 at the Wayback Machine
NHS website carpal-tunnel.net provides a free to use, validated, online self diagnosis questionnaire for CTS
"Carpal Tunnel Syndrome". MedlinePlus. U.S. National Library of Medicine.