Which nerve is affected in tennis elbow tendinopathy?

Tennis elbow, or lateral epicondylitis, primarily involves overuse of the extensor muscles of the forearm, particularly leading to pain at the lateral epicondyle of the humerus. The condition is most closely associated with irritation or injury to the structures around this area, especially affecting the radial nerve.

The radial nerve branches off to provide sensation to the skin of the posterior arm and forearm and innervates various muscles responsible for extending the wrist and fingers. In cases of tennis elbow, the radial nerve can become entrapped or irritated due to the inflammation and microtears associated with the repetitive motions involved in racquet sports.

As the condition progresses, the irritation around the lateral epicondyle can affect the functioning of the radial nerve, contributing to pain, weakness in wrist extension, and altered sensation in the distribution areas innervated by this nerve. The significance of the radial nerve in tennis elbow underlines the injury's mechanical and neurological implications on the patient's movement and pain pattern.

In contrast, the median and ulnar nerves are not typically implicated in tennis elbow, as they run along different pathways in the arm and are associated with other conditions such as carpal tunnel syndrome or cubital tunnel syndrome, respectively.