I. Overview The innervation of the hand mainly comes from the median nerve, ulnar nerve and radial nerve. Since nerve injury not only causes sensory impairment, but also often involves the motor and sympathetic nerve function of the hand, so it has a greater impact on hand function, and if not treated in time, once the small muscles of the hand atrophy, the effect of treatment will be greatly reduced. Therefore, for the hand nerve injury to do timely detection, timely treatment. Second, the causes of hand nerve injury are more, mainly divided into traumatic nerve injury and compression nerve injury. Traumatic nerve injury is mainly due to trauma, while compression nerve injury is often ligament or local swelling for a long time compression of the nerve caused by injury. The overall clinical manifestations of hand nerve injury are sensory, motor and sympathetic nerve dysfunction, as well as positive Tinel’s sign at the site of nerve injury. Sympathetic nerve dysfunction is mainly manifested as sweating dysfunction in the nerve distribution area. Since the innervation areas of different nerves are different, the specific manifestations also vary. 1, the clinical manifestations of median nerve injury median nerve injury, the main distribution area of sensory and sympathetic nerve dysfunction is the palmar side of the radial half of the thumb, the thumb, the middle finger and the ring finger, the motor innervation area is mainly the greater interphalangeal muscle, after the injury is mainly manifested as thumb to palm dysfunction and atrophy of the greater interphalangeal muscle. 2, clinical manifestations of ulnar nerve injury ulnar nerve injury, sensory and sympathetic nerve dysfunction is the main distribution area is the little finger and ring finger ulnar side half of the palmar side and the back of the hand ulnar side half, motor innervation area is mainly the small interphalangeal muscle and intrinsic hand muscle, after the injury is mainly manifested as ring, little finger straightening disorder, split finger, finger dysfunction and fine motor dysfunction, muscle atrophy is mainly manifested as the small interphalangeal muscle and intrinsic hand muscle Atrophy. 3, the clinical manifestations of radial nerve injury radial nerve below the wrist only sensory nerve and sympathetic nerve distribution, its dysfunctional distribution area is mainly the dorsal radial half of the hand. Fourth, the examination of nerve injury after a more specific auxiliary examination is electromyography, but, acute nerve injury for electromyography is often less accurate. Therefore, electromyography is generally used for nerve injury cases with a disease duration of more than one month. For traumatic nerve injuries and closed traumatic nerve injuries, ultrasound or magnetic resonance imaging can also be performed to clarify the location, severity, and cause of the nerve injury. To examine sympathetic nerve injury, an ninhydrin test can be performed to check for sweat secretion in the nerve distribution area. Because this test is not a routine clinical examination, you need to prepare your own ninhydrin test paper, so, less commonly used. V. Diagnosis For hand nerve injury with a clear history of trauma, it is not difficult to make a clear diagnosis based on clinical symptoms and signs. Electromyography can be performed when necessary. If nerve entrapment is suspected, auxiliary imaging is needed to clarify the cause and location of the entrapment. Because of the complexity of neurological diseases, it is important not to think only of the nerve injury of the hand when seeing the sensory and motor dysfunction of the hand, but also other diseases such as neuroinflammatory lesions, tumors of the nervous system, lesions of the central nervous system, and certain systemic diseases (e.g. peripheral neuropathy of diabetes mellitus) should be considered for a comprehensive judgment. VI. Treatment of traumatic hand nerve injury Once the continuity of the nerve is confirmed to be interrupted, in principle, the earlier the repair, the better the functional recovery. If the nerve is disconnected and there is no defect, direct end-to-end suturing is feasible. If the nerve is defective due to severe contamination or old injury, etc., nerve grafting is generally required. Currently, for small finger nerve defects, nerve sheath bridging is feasible to avoid nerve grafting. Nerve sutures require plaster immobilization for about 4 weeks. If continuity of the nerve exists, the nerve can be treated conservatively for a period of time, and the decision to continue conservative treatment or to perform nerve exploration and release surgery will be based on the recovery of the nerve. In the case of entrapment nerve injury, it is necessary to distinguish whether the entrapment is caused by pathological factors (e.g., local mass) or physiological factors (ligament). It should be noted that the treatment effect of nerve injury has a certain degree of uncertainty, because even if the doctor carries out the nerve suture or nerve release well, whether the nerve can fully restore its function depends on the growth of the nerve and the atrophy of the target muscles of the hand. Seven, prevention of traumatic hand nerve injury prevention is mainly to strengthen labor protection, strengthen pre-job training, and enhance the work proficiency of workers. For stuck nerve injury, early treatment of primary disease and reduction of strain is the best means of prevention.