The spontaneous cervical artery dissection (SCAD) is one of the main causes of cerebro-vascular accident in the young adult. It may results from minor cervical trauma. The pathophysiological basis of the neurological complications remain unclear. For that reason, the treatment of SCAD is often empirical. In a retrospective study (1984-1994), we have reviewed 20 cases admitted to Notre-Dame Hospital for a SCAD confirmed by angiography. The initial clinical diagnosis was missed in 65% of the cases despite a suggestive symptomatology (headache 80%, hemiparesis 65% and Horner 45%). We have studied the clinical evolution as related to blood pressure, volemia, haematocrit and the administered treatment (aspirin, Coumadin). 60% of the patients (mean age 39) deteriorated in the hours following their admission. Their was one death (5%) and 85% had neurological sequelae. This study suggest that SCAD is a potentially serious disease. A delayed diagnosis may lead to a poor prognosis. Early aggressive treatment aiming at an optimal cerebral perfusion could improve the patients outcome.