In textbooks on anatomy, radiology and stead of the normal one. An "accessory ar- surgery only the "normal" arterial blood tery" is a second artery ip addition to the one normally present, without any specifi- supply is usually described. This "nor- mality", however, is sometimes found in cation of size being made. However, there less than 30% of all cases for some arteries, is no general agreement on whether minute but in over 95% for others. Rarely men- vessels with very small diameters and hard- tioned are deviations in the individual ar- ly any significant blood flow should also be tery's...