[Morphological changes in arterial ruptures]

The historical opinion that the intima layer of a ruptured artery of muscular type could stop bleeding by "rolling in" should be controlled experimentally. Five segments of human femoral/popliteal artery (3-4 cm long) were overstretched until complete rupture occurred. Furthermore a longitudinally split and a partially oblique incised segment were ruptured. As morphological finding a sandclock deformity was observed in the region of rupture. This phenomenon was induced by adventitia layer, which closed the ends of ruptured media layer like a Chinese finger trap. In the longitudinally split segment a transverse rupture of the media layer could be observed, while the fibers of adventitia layer were pulled out when the traction was continued. Neither macroscopical nor microscopical signs could be found for "rolling in" of intima or media layer. The reason for spontaneous hemostasis after arterial rupture is more likely the activation of platelets by collagenous fibers of adventitia layer than "rolling in" of intima or media layer. If there is no finger trap mechanism of adventitia layer like in shot- or stab wounds a massive blood loss must be expected.