Coronal Section - Internal Capsule

The internal capsule is a compact, V-shaped bundle of white matter fibers situated between the caudate nucleus and thalamus medially and the lentiform nucleus laterally. Its anterior limb carries frontopontine and thalamocortical fibers, the genu contains corticobulbar fibers controlling cranial nerves, while the posterior limb contains the corticospinal tract and major sensory pathways. Owing to the dense concentration of motor and sensory fibers, even a small lesion, particularly from a lacunar infarct due to hypertension, can produce profound neurological deficits, including contralateral hemiplegia, hemisensory loss, facial weakness, and dysarthria. The internal capsule is therefore regarded as the brain's "information superhighway," transmitting nearly all voluntary motor commands and sensory information between the cerebral cortex and the rest of the body