Fig. 23-2. Mirror images of the pericardial reflections. A, The reflections onto the heart, viewed from behind. The arrow indicates the transverse sinus of the pericardium. B, The heart removed, and the posterior part of the pericardium viewed from in front. The reflection at the veins forms an irregular continuous line that begins at the inferior vena cava, extends up to the lower right pulmonary vein, and turns to the left across the left atrium to the left pulmonary veins. The irregular space thereby bounded is the oblique sinus of the pericardium (arrow). Click for high resolution image.