Remove the heart from the middle mediastinum.

1. Identify the fibrous pericardium. Use scissors to cut the pericardium from the apex of the heart, along the left border, across the pulmonary trunk, ascending aorta and superior vena cava, and back to the diaphragm along the right border. Reflect the anterior aspect of the pericardial sac towards the diaphragm. (G 3.44;N 209;Gl 9.6B)
2. Place your hand posterior to the heart in the pericardial sac. Extend your hand in the superior direction until you feel the pulmonary veins. Your fingers are touching the visceral and parietal serous pericardium lining the oblique pericardial sinus. (G 3.46;N 209;Gl 9.8) Remove your hand and place your right index finger between the left upper pulmonary vein and the base of the pulmonary trunk. Extend your finger posterior to the ascending aorta and finally anterior to the superior vena cava. Your index finger is in the transverse pericardial sinus.
3. Cut the ascending aorta and pulmonary trunk at the level of the transverse pericardial sinus. Cut the superior vena cava at the same level (make certain this cut is inferior to the arch of the azygos vein). (G 3.46;N 209;Gl 9.3) Cut the pulmonary veins as close to the heart as possible without damaging the left atrium. Finally, elevate the heart and cut the inferior vena cava approximately 1 cm inferior to the right atrium. Remove the heart from the pericardial sac and observe the location of the oblique pericardial sinus