Final answer:
Carpal tunnel syndrome occurs when the median nerve in the wrist becomes compressed, leading to pain, numbness, and tingling in the thumb and first two fingers. Referred pain may cause the perception of pain in the arm due to misinterpretation of sensory signals by the brain. Treatment options include wrist splints, corticosteroid injections, or surgery.
Step-by-step explanation:
Carpal tunnel syndrome occurs when the median nerve in the wrist becomes compressed between the carpal bones. This can be caused by repetitive use of the wrist, trauma to the wrist, or other factors. The compression of the median nerve can result in symptoms such as pain, numbness, and tingling in the thumb and first two fingers of the hand.
The sensation of pain on gentle touching of the arm in this case is likely due to referred pain. Referred pain occurs when particularly strong visceral sensations are felt in unexpected places. In the case of the damaged median nerve, the brain misinterprets the sensations from the mediastinal region as being from the axillary and brachial regions, leading to the perception of pain in the arm.
Treatment options for carpal tunnel syndrome include wearing a wrist splint, receiving corticosteroid injections, or surgery to cut the carpal ligament and reduce pressure on the median nerve.