Inclusion Criteria:  ages ranged 30-75 compliance to MRI scan no MRI contraindication (Patients) clinical diagnosis of CSM and surgery in our hospital (Healthy controls) no spinal cord dysfunction  Exclusion Criteria:  prior head or neck surgery or accompanying diseases with neurologic deficits and/or symptoms including multiple sclerosis, spinal cord injury, motor neuron disease, or spinal cord tumour images with motion artifact