To determine the spatial extent of shock-wave-induced vascular damage human umbilical cords were exposed to electromagnetically generated, focused ultrasound waves of different energy densities. During treatment macroscopically visible hematoma and superficial holes appeared. Following exposure specimens were fixed and examined histologically. In addition to vessel wall necrosis and rupture, complete detachment of endothelial cells in defined regions was observed. A correlation of the extent of the damage with the energy density distribution revealed that a local energy density of 0.3 mJ/mm2 is the lower threshold for the occurrence of severe vascular damage.