Li xx, male,42 years old ,odontoid fracture with atlantoaxial subluxation,neck pain before operation muscle force of exremities is  3-4 degree,the patient had a operation of posterior fusion of Atlantoaxial and external fixation with vertebral root screw.After operation ,the neck pain disappeared ,and when left  hospital ,the muscle tension recovered to normal,and muscle force reached to 4-5 degree.