My nan has a trapped nerve what is a trapped nerve?

Entrapped nerve: A band of fibrous tissue can compresse a nerve which leads to pain, numbness, and weakness. The most common location is the median nerve at the wrist (carpal tunnel syndrome). Other common locations are the ulnar nerve at the elbow (cubital tunnel syndrome), common fibular nerve at the knee, and tibial nerve at the ankle (tarsal tunnel syndrome). See a neurosurgeon for evaluation.