Conclusion With the referential range of the normal natural angle between medulla oblongata and upper spinal cord,we can make a diagnosis of basilar invagination by MRI.

• 结论对于颅底凹陷症的诊断，MR能够直接显示脑桥延髓受压的情况，在MRI成像中可以应用参考上述正常参考值对于该疾病作出正确的诊断。