Corona radiata

The corona radiata is a fan-shaped sheet of projection fibres within the cerebral white matter. It forms the superior continuation of the internal capsule and spreads superiorly into the centrum semiovale, with its fibres radiating toward widespread areas of the cerebral cortex. Thus, the projection fibres are densely compacted as they pass through the internal capsule but spread out as they approach the cortex.

It contains both ascending (afferent) and descending (efferent) fibres and carries a major proportion of neural traffic to and from the cerebral cortex. Ascending thalamocortical fibres convey sensory and other information from the thalamus to the cortex, whereas descending corticofugal fibres include the corticospinal, corticobulbar and corticopontine fibres, which connect the cortex with lower centres in the brainstem and spinal cord.

Functional and clinical correlates

Functionally, the corona radiata is therefore a major communication pathway linking the cerebral cortex with the thalamus, brainstem and spinal cord. Clinically, small subcortical infarcts involving the corona radiata can interrupt motor and sensory pathways, producing contralateral weakness and/or sensory deficits depending on the fibres affected.