Knowledge of physiological flow velocities in the carotid arteries belongs to basic orientation when assessing pathological states. We analyzed systolic and diastolic velocities in the common (CCA), external (ECA) and internal (ICA) carotid arteries, and the values of resistance and pulsatility indices in 199 persons with normal ultrasonographic findings (diffuse atherosclerotic changes were acceptable). Values were correlated with the age of examined persons in the range of 21–92 years. Results: The average maximum systolic velocity in the CCA dx/sin 62/64 cm/s rises in the ECA to 79/80 cm/s, in the ICA to 72/75, despite the common rule that velocity in somatic arteries drops after bifurcation. Velocity of systolic and diastolic flow decrease during life in all three arteries, with the following yearly rate: in the right CCA 6.44 mm/s/year (p<0.001), left 7.39 mm/s/year (p<0.001), in the ECA more slowly, 3.1 mm/s/year on the right (p<0.022), 3.21 mm/s/year on the left (p<0.005). The ICA maintains its systolic velocities relatively the best, as it loses yearly only 2.32 mm/s on the right (p<0.016) and 2.30 mm/s on the left (p<0.017). The yearly decreases of diastolic velocities in all three carotid arteries on both sides range between 1.72 and 2.28 mm/s (all p<0.001). Resistance indices in both CCA, 0.78/0.78, drop after the bifurcation in the ICA to 0.67/0.66. In the ECA, they are the highest of all the three carotid arteries, namely 0.86/0.85. In the ICA the index increases during lifetime (0.0018/0.0017 per year), similar to the ECA (0.0020/0.0016 per year). Pulsatility indices with average values of 1.79/1.84 in the CCA, increase after the bifurcation in the ECA to 2.40/2.35, whereas in the ICA they drop bilaterally to 1.2. Pulsatility indices increase moderately with age only in both filial arteries.

        Key words: systolic and diastolic velocity, carotid arteries, resistance index, pulsatility index, physiology, age