(a) This dissection of a cadaver viewed from the front shows the course of the right and left phrenic nerves. (b) Dissection of the left phrenic nerve, which descends onto the fibrous pericardium anterior and lateral to the aortic arch, alongside the distal part of pulmonary trunk (PT), left atrial appendage (LAA), and the lateral wall of the left ventricle. (c) Left lateral volume rendered CT image of the heart shows the anatomic course of left phrenic neurovascular bundle (shown in green and demarcated by yellow arrows) in relation to the LAA. Corresponding two-dimensional axial CT at the superior margin of the LAA (red arrow) is also shown (inlay images). Neurovascular bundle is usually seen as a single trunk anterior or over the body of LAA. In 23% of individuals, the nerve moves over the neck of LAA. LS = left superior pulmonary vein, Ao = aorta, Eso = esophagus, LB = left bronchus, RPN = right phrenic nerve, and LI = left inferior pulmonary vein.
