Pathological synergies are a frequent consequence of cerebrovascular accidents and hinders further recovery. The existing concept of the formation of pathological synergies considers them as a compensatory strategy in response to damage to the pyramidal tract, which, due to paresis and increased muscle tone, has acquired a pathological character. Recent studies in primates have shown that the contralateral hemisphere, in particular the reticulospinal and rubrospinal tracts, may be involved in motor control of the hand. The current hypothesis presents the corticoreticulospinal and corticorubrospinal tracts as a back-up system for neuronal reorganization due to injury.
 This clinical case describes the role of the white matter of the contralateral hemisphere in the mechanism of formation of pathological flexion synergy, based on data from the analysis of movements and neuroimaging.