Artery of Adamkiewicz
In human anatomy, the artery of Adamkiewicz (also arteria radicularis magna) is the largest anterior segmental medullary artery. It typically arises from a left posterior intercostal artery at the level of the 9th to 12th intercostal artery, which branches from the aorta, and supplies the lower two thirds of the spinal cord via the anterior spinal artery.
Bühler's anastomotic artery
In human anatomy, Bühler's anastamotic artery (also called the arc of Bühler) is an anastomotic shunt joining the superior mesenteric artery and the celiac trunk in vertical orientation. As the aforesaid arteries arise separately from different levels of the abdominal aorta, the shunt provides limited collateral circulation should a blockage occur in the intervening arterial segment. Bühler's artery is a rare phenomenon present in up to 3% of the population, and is thought to be an unobliterated remnant of the ventral longitudinal anastomosis present during embryological development.