It is proposed that repetitive use of the arm can affect the biomechanics of the upper limb or cause damage to tissues. It is proposed that postural and spinal assessment along with ergonomic assessments should be considered, based on observation that addressing these factors has been found to improve comfort in some studies although experimental data are lacking and the perceived benefits may not be specific to those interventions. A 2010 survey by NIOSH showed that 2/3 of the 5 million carpal tunnel diagnosed in the US that year were related to work. Women are more likely to be diagnosed with work-related carpal tunnel syndrome than men. Associated conditions
A variety of patient factors can lead to CTS, including heredity, size of the carpal tunnel, associated local and systematic diseases, and certain habits. Non-traumatic causes generally happen over a period of time, and are not triggered by one certain event. Many of these factors are manifestations of physiologic aging. Diagnosis
There is no consensus reference standard for the diagnosis of carpal tunnel syndrome. A combination of characteristic symptoms (how it feels) and signs (what the clinician finds on exam) are associated with a high probability of IMNCT without electrophysiological testing. Electrodiagnostic testing (electromyography and nerve conduction velocity) can objectively measure and verify median neuropathy.Ultrasound can image and measure the cross sectional diameter of the median nerve, which has some correlation with idiopathic median neuropathy at the carpal tunnel (IMNCT). The role of ultrasound in diagnosis--just as for electrodiagnostic testing--is a matter of debate.
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.