regional_part_of White matter structure of cerebral hemisphere Extreme capsule Extreme capsule is an organ subdivision of the telencephalon which is made up primarily of myelinated axonal neural tissue (white matter). The extreme capsule is a sheet-like fiber bundle located lateral to the clausturm and medial to the insula which projects dorsally to the white matter underlying the cerebral cortex. FMA:61960 fma Capsule of cerebral hemisphere