Weakness from a blow to the neck is considered to be possibly related to joint dislocation, nerve damage, soft tissue injury and other causes. 1. A blow to the neck is likely to lead to dislocation of the joints in the neck. Dislocated joints may compress the blood vessels and nerves, leading to weakness. 2. A blow to the neck may also lead to nerve damage, affecting the normal physiological function of the muscles innervated by the nerve, which may also lead to weakness. 3. It may also lead to soft tissue injury. Localized hematoma may compress the blood vessels and nerves, affecting blood circulation, which may also lead to weakness. There may be other clinical reasons for weakness after a blow to the neck. It is recommended to go to the orthopedic department of the hospital as soon as possible, and cooperate with the doctor to improve the CT, MRI and other related examinations, in order to clarify the cause of the disease.