Figure 1D

T2 weighted axial image through the plane of the foramen magnum in a patient whose symptoms were consistent with a Chiari type-1 malformation. The neurological examination was remarkable for diffuse hyper-reflexia and a left Babinski response. Note that the cerebellar tonsils are herniated into the lateral foramen magnum. CSF is evident in the dorsal midline(arrow).The ventral medulla oblongata(m) is deformed by the vertebral arteries which are applied to it. In accordance with our criteria, this foramen magnum would be considered crowded.