Hand numbness: In addition to the median nerve, there is another nerve that plays an important role in the sensory and motor function of the hand: the ulnar nerve. The ulnar nerve innervates sensation on the ulnar side of the little finger and ring finger (near the little finger side), as well as most of the intrinsic muscles of the hand. What happens after an injury to the ulnar nerve? As an example, a few years ago a professor came to see me about his hand, saying that he had been seeing a cervical spine patient for almost a year and was not getting better, and in recent months he had some difficulty even holding the key to the door. After listening to his description and examining the sensory and motor functions of his hand, I found that the sensation on the ulnar side of his little finger and ring finger was numb, the muscles on the back of his hand were obviously atrophied and much thinner compared to the healthy side of his hand, and the strength of the affected hand to split and join fingers was very weak. This is a typical symptom of chronic entrapment of the ulnar nerve. Unfortunately, although the numbness in this professor’s hand improved a lot after the surgery, the motor function of his hand could not be fully restored.