[Study on cross-sections at the plane of the aortic arch and its adjacent structures]

The purpose of this study was to describe and explain the normal appearances of aortic arch and its adjacent structures on the transaxial sections and to provide anatomical data for the diagnosis of CT and MR images. Dissections were performed on 1.2 cm interval cross-sections of the thorax of 30 embalmed cadavers. The results showed 20.00 +/- 7.30% of the aortic arch and arch of the azygos vein at the same plane and 40.00 +/- 8.94% of the arch of the azygos vein at the level of concavity of the aortic arch. 80.00 +/- 7.30% of the top of the superior aortic recess extended to the level of the aortic arch from which the branchiocephalic trunk arises. At the level of the aortic arch, 100% of the lymph nodes of superior vena cava were located among the aortic arch, superior vena cava and trachea. At the level of azygos vein, 100% of the lymph nodes of azygos vein and the superior aortic recess were located among the superior vena cava, arch of azygos vein, trachea and concavity of aortic arch. These data suggest that aortic arch and arch of azygos vein are the key structures to identify the superior aortic recess and lymph nodes. They are essential for understanding the related pathologic changes depicted on CT and MR images.