Two patients with posttraumatic dissection of the internal carotid artery were referred to the neurosurgical department with secondary neurological deterioration following a minor head injury with concussion. Both developed aphasia and right hemiparesis during the first few hours after the accident; one patient also had right focal seizures. On admission, both were only mildly lethargic, which contrasted with the severity of the focal neurological signs. Early CT scan was normal in both cases, whereas cerebral blood flow (CBF) studies by single photon emission computerized tomography (SPECT) with Tc-HMPAO (Ceretec) showed perfusion defects in the region supplied by the left middle cerebral artery (MCA), correlating with the clinical picture. Doppler sonography disclosed pathologic flow patterns, and carotid angiography demonstrated dissection of the internal carotid artery, in one patient on the left only and in the other bilaterally, with embolic occlusion of a branch of the left MCA in the latter case. Clinical features, pathogenesis, diagnostic workup and possible treatment (medical, as in our two cases, versus surgical) of this rare pathology are briefly reviewed.