Monoplegia is a paralysis of one of the patient’s extremities. Monoplegia can be caused by peripheral neuropathy as well as central neuropathy. Although this type of monoplegia is not the most serious, it is not as easy to improve in treatment as other common types because it is relatively rare. Examination methods: 1. Wound examination: Check for wounds. If there is a wound, the extent and depth, soft tissue damage, and the presence of infection should be examined. Identify the trajectory of the gunshot blind or penetrating wounds, the presence of fractures and dislocations. If the wound has healed, the scar situation and the presence of aneurysm and arteriovenous fistula formation should be observed. 2.Limb posture: wrist ptosis after monoplegia, claw-like fingers after ulnar nerve injury, i.e., hyperextension of the metacarpophalangeal joints of the 4th and 5th fingers, and flexion of the interphalangeal joints. After injury to the median nerve, the deformity of “ape hand” appears, i.e., interphalangeal paresis, with the thumb parallel to the other fingers. Injury to the common peroneal nerve results in foot drop. 3.Motor function examination: according to the degree of muscle paralysis to determine the nerve injury, generally use the 6-level method to distinguish muscle strength. M “0” level: no muscle contraction. M “1” level: slightly contracted muscles. M “2” level: the joint has movement, and can actively move the joint in a certain direction to reach full mobility without fighting against gravity. M “3” level: full joint motion is achieved against gravity, but not against resistance. M “4” level: the joint can move completely against resistance, but the muscle strength is poorer than the healthy side, M “5” level: normal. 4.Sensory function examination: The sensory fibers of the nerve have a certain distribution area on the skin, check the range of sensory loss or disappearance, can determine what nerve damage. Generally, only the pain and touch sensation can be checked. Neighboring sensory nerve distribution area has overlapping innervation phenomenon, the nerve injury within a few days after the sensory loss range gradually reduced, but does not indicate that the nerve has been restored, but the adjacent nerve instead of the function of a limited expansion, and finally only the nerve distribution area alone without any sensory recovery.