The painful arm.

The painful arm often presents a diagnostic challenge. The cause is often obvious, especially with regional pain syndromes including the carpal tunnel and the tennis elbows. However, pain reference syndromes can be confusing and it is advisable to first examine the cervical spine because it is a common and often overlooked cause of arm pain or paraesthesia. It is common for arm pain to cause sleep disturbances and in such cases it is worth considering cervical causes, carpal tunnel syndrome and the thoracic outlet syndromes. The working rule is: patients with thoracic outlet syndrome cannot fall asleep; a carpal tunnel lesion wakes the patient in the middle of the night; and cervical spondylosis wakes the patient with pain and stiffness that persists well into the day.