Proximal weakness due to injury of the corticoreticular pathway in a patient with traumatic brain injury.

BACKGROUND: The corticoreticular pathway (CRP) innervates the proximal muscles of extremities and axial muscles; therefore, it is involved in postural control and gait. We report on a patient who exhibited proximal weakness due to a CRP injury, which was evaluated using diffusion tensor tractography (DTT).

METHODS: A 62-year-old male patient who had been injured in a traffic accident underwent conservative management for a contusional hemorrhage in the right frontotemporal lobes, and a subdural and epidural hematoma in the right temporoparietal lobes. The patient exhibited right proximal weakness (shoulder: 3+, hip: 3+) at two weeks after onset. Findings on brain MRI revealed encephalomalactic lesions in both frontal lobes.

RESULTS: Findings on DTT of the left CRP showed discontinuation at the midbrain level; in contrast, the integrities of the corticospinal tract in both hemispheres were maintained from the cerebral cortex to the medulla along the known pathway of the corticospinal tract.

CONCLUSION: The proximal weakness of the right shoulder and hip observed in this patient appeared to be attributed to injury of the left CRP.