The lateral bulbar syndrome is a heterogeneous clinical condition. It is usually of vascular origin, due to a reduction in postero inferior cerebellar artery (PICA) and vertebral artery blood flow. We studied two cases: a woman aged 59 years and a man of 49 years, who were admitted with Wallenberg s syndrome. The diagnosis was confirmed on magnetic resonance which showed an ischaemic lesion in the lateral bulbar region ipsilateral to the clinical signs. On angioresonance there was lack of filling of the vertebral artery involved, and the PICA was not seen. At the present time, the most sensitive technique available for the diagnosis of the lateral bulbar syndrome is cranial magnetic resonance (it even appears to be useful for making aetiopathogenic hypotheses). Similarly, arteriography is widely used for assessing disorders of the posterior cerebral circulation, although it is not without risk. According to recent studies, angioresonance gives sensitivity and specificity of over 75% when used to assess anomalies of the vertebral and basilar arteries. So our observations corroborate the finding that angioresonance is a very sensitive, specific investigation for showing disorders of the vertebral arteries and PICA, which spares patients the morbidity associated with conventional arteriography.