Typically, the accessory renal artery courses into the renal hilum to perfuse the upper or lower renal poles. They may also enter the renal parenchyma directly from the renal cortex (called a polar artery). Rarely, they may arise from the lower thoracic aorta, as well as from the lumbar and mesenteric arteries.
The chain rule can be used to find whether they are getting closer or further apart. For example, one can consider the kinematics problem where one vehicle is heading west toward an intersection at 80 miles per hour while another is heading north away from the intersection at 60 miles per hour.
A chain is a unit of length. A chain measures generally between 60 and 100 feet. If not otherwise qualified, the chain as a unit normally refers to the English unit chain, also called a Gunter's chain. This is defined as 66 feet (20.1168 metres). It is also known as the surveyor's chain or land chain. chain is a unit of length. A chain measures generally between 60 and 100 feet. If not otherwise qualified, the chain as a unit normally refers to the English unit chain, also called a Gunter's chain. This is defined as 66 feet (20.1168 metres). It is also known as the surveyor's chain or land chain.