Transverse pericardial sinus
The transverse pericardial sinus is an area of the pericardial cavity located behind the aorta and pulmonary trunk and anterior to the superior vena cava. When entering the transverse pericardial sinus, a surgeon will insert an index finger between the aorta and pulmonary trunk on the ventral side and the superior vena cava on the dorsal side. The oblique pericardial sinus is an area of the pericardial cavity located behind the left atrium of the heart. If a surgeon places fingers under the apex of the heart, then moves the fingers until they are stopped by a pericardial reflection, then the fingers are in the oblique sinus. You should understand what these two sinuses are and how they can be entered!
The cardiac notch is a structure on the left lung which separates the lingula below from the upper portion of the superior lobe of left lung. The coronary sinus is a venous sinus on the posterior surface of the heart which receives blood from the smaller veins which drain the heart. The coronary sulcus is a groove on the heart, between the atria and ventricles. The coronary sinus, circumflex artery, and right coronary artery lie in the coronary sulcus.