The brachial plexus is an important nerve that innervates the upper extremity. Brachial plexus injuries are easily caused when external forces separate the head and shoulder in opposite directions. Mechanism of injury: Most brachial plexus injuries in adults occur as a result of a pulling injury in a motorcycle or automobile accident. If a person falls from a motorcycle, the head or shoulder hits an obstacle or the ground, causing the head and shoulder to be in a separated position, the brachial plexus is subject to excessive strain injury, and in mild cases there is nerve concussion and temporary dysfunction, in severe cases the nerve axon is broken and the nerve root cadre is fractured. Heavy objects smashed into the shoulder, upper limbs inadvertently by the machine, transport belt involvement can also cause brachial plexus injury. Neonatal brachial plexus injury is seen when the mother’s head is first exposed during obstructed labor, using a fetal head suction device or using forceps, resulting in separation of the baby’s head from the shoulder and excessive pulling and injury to the brachial plexus, mostly incomplete. Presentation: After injury to the brachial plexus, the muscles innervated by the corresponding nerve branches are paralyzed and the skin feels numb. Shoulder abduction disorder, deltoid atrophy, shoulder subluxation, elbow flexion disorder, biceps atrophy, numbness of thumb and index finger, triceps muscle weakness, flexor muscle atrophy or dysfunction, intra-hand muscle atrophy and dysfunction may occur. Generally, there are upper brachial plexus injuries, lower brachial plexus injuries, and total brachial plexus injuries. In case of total brachial plexus injury, the whole upper limb muscle paralysis, low muscle tone, loss of sensation in the upper limb other than the medial one, loss of tendon reflexes, and Horner’s sign may also appear. Examination:Electrophysiological examination and CTM, MRI, etc. Treatment:The aim is to reduce permanent disability and to restore or improve upper limb function. Due to the different degrees of pathology of brachial plexus injuries, regular review is required to accurately record the functional status and recovery of the neuromuscles. Generally nerve concussion injuries tend to recover function within 3 weeks, and axonal rupture injuries tend to begin to recover function and progress within 3 months, and can continue to be observed. On the contrary, if functional recovery is not seen within 3 months, nerve rupture injury or imaging diagnosis of radicular avulsion injury is considered, and early brachial plexus surgical exploration is recommended.