Skull base entrapment is a bony deformity of the greater occipital foramen, caused by the protrusion of the dentate process of the cardinal vertebrae into the greater occipital foramen, which compresses the medulla oblongata, higher cervical medulla, cranial nerves and pulls on the spinal nerves causing the corresponding symptoms and signs. It may be accompanied by subungual herniation of the cerebellar tonsils, atlanto-axial subluxation, atlanto-occipital fusion and spinal cord cavity. The diagnostic significance of imaging is decisive. X-rays of the occipitocervical junction, X-ray sagittal tomography and CT of the skull base are of definite significance for the diagnosis of bony structural abnormalities, while MRI examinations show better the compression status and internal changes of the spinal cord, brainstem and cerebellum, and enhanced scans in the sagittal position can also indicate the degree of local dural thickening. Measurement of the distance of the dentate process over the Chamberlain line, the Klaus height index, and the medulla cerebral bridge angle can help in the selection of treatment options. The pathological factors requiring surgical management of skull base entrapment are mainly static spinal cord compression and dynamic spinal instability after decompression. The main reported decompression surgical approaches are suboccipital decompression by posterior median approach, anterior decompression by trans-oral pharyngeal approach and lateral decompression by posterior occipocervical approach. The cervical medulla cerebral bridge angle is selected according to the size of the cervical medulla cerebral bridge angle. For those with cervical medulla cerebral bridge angle <130º, because the medulla and cervical medulla are obviously compressed ventrally, transoral pharyngeal dentate removal is performed first, followed by posterior decompression for occipitocervical fixation and bone fusion; for those with cervical medulla cerebral bridge angle >130º, only posterior suboccipital decompression is performed. After decompression, the stability of the atlantoaxial intervertebral space was reestablished by internal fixation.