Figure 11d. Pericardial recesses and sinuses. (a) Drawing illustrates the pericardial sac with the heart removed. Note that the transverse sinus (T) and oblique sinus (*) are separated by pericardial reflections. Note also the extension of the pericardium superiorly. The pulmonic vein recesses (arrows) lie between the superior and inferior pulmonary veins. (b, c) Axial contrast-enhanced cardiac-gated images of the heart obtained at (b) and inferior to (c) the level of the right inferior pulmonary vein show areas of fluid attenuation anterior, posterior, and inferior to the vein (arrowheads). (d, e) Sagittal (d) and coronal (e) reformatted images from CT data show the relationship between the fluid in the pulmonic vein recess (arrowhead) and the pulmonary vein.