Rupture of the aorta accounts for a significant proportion of fatalities following blunt trauma. A great deal of consensus exists describing the circumstances under which acute traumatic aortic dissection occurs as well as its investigation and management. However, there remains some controversy surrounding the pathogenic aetiology underlying this injury. Univariate and multivariate models of blunt traumatic aortic rupture (BTAR) are discussed. To account for the consistency in the nature of BTAR, despite a range of trauma scenarios, the concepts of dynamic multivariate models and a final common pathway are introduced. Clinical management is described elsewhere. Greater understanding of the mechanism of BTAR could lead to a range of safety systems aimed at a reduction in its incidence and severity.