Figure 1.

Representative axial section of left frontal cortex with cortex in light grey and lateral ventricle in dark grey (A). White matter lesions are shown in red. TMF, tumefactive lesion—note size >3 cm and extension from ventricular surface to juxtacortical zone; PV, periventricular—note lesions abutting or immediately adjacent to lateral ventricle; CT, cortical—lesion wholly or predominantly located with the cortex; JC, juxtacortical—subcortical white matter lesion following the contour of the cortex but sparing the U-fibre layer; SC, subcortical—any other lesion predominantly located superficial to an imaginary line drawn half-way between the lateral ventricular surface and the cortex. Diagrammatic representation of axial section of spinal cord showing quadrantic segmentation of central and peripheral zones used to define lesions, showing (B) a central spinal cord lesion occupying at least a part of all central quadrants and (C) a partial spinal cord lesion occupying part of only three central regions.