Which muscle is crucial to test in a suspected case of radial nerve palsy?

The brachioradialis muscle is innervated by the radial nerve and is primarily responsible for flexing the forearm at the elbow, especially when the forearm is in a neutral position (thumbs up). In cases of radial nerve palsy, testing the brachioradialis muscle helps determine the integrity of the radial nerve. If the brachioradialis is weak or non-functional, it indicates a potential issue with the radial nerve. This muscle is particularly useful in differentiating radial nerve palsy from other nerve injuries, as it is not affected by lesions of the median or ulnar nerves.