Ergonomics expert witness John D. Lloyd, Ph.D., M.Erg.S., C.P.E., writes on Carpal Tunnel Syndrome (CTS):
Symptoms of CTS are usually experienced in the region of the hand served by the median nerve. This encompasses the second to forth fingers and base of the thumb on the palmer side, and backs of the first four fingers on the dorsal side.
Acute CTS is often associated with nocturnal pain and tingling, episodic tingling during the workday and gradual numbness, all of which may be encouraged by certain activties such as abnormal postures, or repetitive or forceful hand motions. Symptoms usually diffuse shortly after the activity is changed.
As severity increases the patient may experience aching, tingling and what has been described as ‘painfull numbness’ in the fingers of the median distribution and deep in the palm. Perceptually the patient may recall subjective feelings of uselessness related to the affected hand and wrist, mental sensation of swelling (although not apparent on inspection), clumsiness, and difficulty performing everyday tasks, such as unscrewing a bottle cap.
At the most severe level, patients with CTS may experience dull aching throughout the limb which radiates not only distal to the site of compression, but also proximally. Patients may report pain throughout the forearm, upper arm, shoulder, and even the neck. Changes in coloration of the skin become more apparent, especially with exposure to cold. There may be excessive sweating in the palm and a possible mild degree of edema which has been related to vasomotor imbalance. Wasting of the thenar muscle and mild weakness of the abductor pollicis brevis or opponens pollicis muscle may also be observed in severe cases.