ABSTRACT
This figure is an example of a false plane that can develop in the process of opening the ICA lumen. The Penfield No. 4 retractor is situated in the true lumen of the vessel, and it can be seen that the Potts scissors went through the atheroma of a false plane and eventually burst into the true lumen in the ICA. There are no untoward consequences from a false dissection of this type in opening the vessel; however, it should be emphasized that the surgeon must ascertain the true lumen of the ICA either by direct inspection or visualization of backbleeding before any attempt at shunt placement.
