The human thalamocortical sensory path in the internal capsule: evidence from a small capsular hemorrhage causing a pure sensory stroke.

A patient is presented who suffered a strokelike event during life that resulted in a hemisensory dificit for some modalities. On pathological examination of the brain, the lesion responsible for the deficit was found to be a small slit hemorrhage located in the posterior limb of the internal capsule adjacent to and minimally involving the thalamus. Clinicopathological correlation suggests that the sensory thalamocortical radiations must lie farther posterior in the posterior limb of the internal capsule than the corticospinal motor fibers, and that they probably lie adjacent to the thalamus. The case emphasizes that small slit hemorrhages deep in the brain, although rare, must be considered in the differential diagnosis of sudden hemisensory deficits.