Swelling of the knuckles is the main symptom of ulnar deviation. Other signs and symptoms include: Loss of ability for the thumb to oppose the index finger Warmth in your wrist, hand, and finger ...

wkes.eu The extensor carpi ulnaris (ECU) muscle plays a key role not only in the active movements of wrist extension and ulnar deviation but also in providing stability to the ulnar side of the wrist.