The longitudinal movement of the arterial wall has gained little interest. It has been assumed that this movement is negligible compared with the diameter change. Using a new high-resolution non-invasive ultrasonic method we measured the longitudinal movements and the diameter change of the common carotid artery of 10 healthy humans. During the cardiac cycle a distinct bidirectional longitudinal movement of the intima-media complex could be observed in all investigated subjects. In early systole an antegrade longitudinal movement, i.e., a movement in the direction of the blood flow, was seen (0.39 ± 0.26 mm). This was later in systole followed by a retrograde longitudinal movement, i.e., a movement in the direction opposite to the blood flow, (-0.52 ± 0.27 mm). In diastole, a second antegrade longitudinal movement followed (0.41 ± 0.33 mm). The corresponding diameter change was 0.65 ± 0.19 mm. The adventitial region showed the same basic pattern of longitudinal movement, however, the magnitude of the movements was smaller than that of the intima-media, thereby introducing shear strain, and thus shear stress, within the wall (maximum shear strain between the intima-media and the adventitial region 0.36 ± 0.26 radians). These are phenomena that have not previously been described. Measurements were also performed on the abdominal aorta (n=3), the brachial (n=3) and the popliteal (n=3) arteries. The results are all completely new information, which seems to be of fundamental importance for the further study and evaluation of vascular biology and hemodynamics, and thus for the study of atherosclerosis and vascular diseases.