Lifting the back of the hand without strength is generally caused by damage to the radial nerve, the specific causes may be trauma leading to joint dislocation or fracture, frozen shoulder, cervical spondylosis, etc.. 1. Trauma leading to joint dislocation or fracture: if the arm is traumatized and the shoulder and elbow joints are fractured or dislocated, it may lead to damage of nerves and blood vessels, which may cause ischemia or compression of the radial nerve, resulting in the relaxation of the muscles of the back side of the small arm, which can’t exert force, and is manifested as a lack of strength in lifting the back of the hand. 2. Frozen shoulder: generally due to long-term strain caused by inflammation of the shoulder joint and the surrounding tissues, resulting in inflammatory hyperplasia or swelling, compression of the brachial plexus, resulting in compression of the radial nerve and difficult to innervate the muscles of the small arm dorsal side of the back of the hand is difficult to lift. 3. Cervical spondylosis: If the cervical disc herniation may cause the brachial plexus to be compressed, which may lead to the radial nerve compression and difficult to play a role. If you have weakness in lifting the back of the hand, it is recommended that you seek medical attention to identify the specific cause of the problem and receive relevant treatment.