The weakness of the right arm now after the injury may be caused by muscle injury, cervical spondylosis, brachial plexus injury, peripheral neuritis and fracture and other diseases. 1. Muscle injury: the right arm is a functional limb, which is easy to cause muscle fatigue or injury, and the symptoms can be relieved by rest and medication. 2. Cervical spondylosis: due to long-term poor sitting posture, looking down at the cell phone, etc., resulting in cervical degeneration, compression of the nerves innervating the arm, soreness, weakness, shoulder can not be lifted up after arm injury and other phenomena. 3. Brachial plexus nerve injury: trauma leads to brachial plexus nerve injury or trauma secondary to thoracic outlet syndrome or, the location of the nerve outlet due to bone, ligament lesions compression, irritation, muscle soreness. 4, peripheral neuritis: after trauma because of wound inflammation or scar compression and adhesion of peripheral nerves, peripheral neuritis. The clinical symptoms of arm pain and weakness will also appear. 5. Fracture: Fracture is the interruption of the integrity or continuity of the bone, if the patient accidentally falls, falls, impact, traffic accidents, may lead to right side geb fracture. Patients may show localized pain, pressure pain, dysfunction, deformity, and patients may present with right arm injury now weakness. There are many reasons that lead to the right arm injury now weakness, it is recommended that patients promptly identify the cause of the disease and take relevant treatment measures.