Great vessels of the heart
A. Ascending Aorta
- Takes its origin from the left ventricle within the pericardial sac and ascends behind the sternum to end at the level of the sternal angle.
- Lies in the middle mediastinum, has three aortic sinuses located immediately above the cusps of the aortic valve, and gives off the right and left coronary artery.
B. Arch of the Aorta
- Is found within the superior mediastinum, begins as a continuation of the ascending aorta, and arches over the right pulmonary artery and the left main bronchus.
- Forms a prominence that is visible on the radiograph as the aortic knob.
- Gives rise to the brachiocephalic, left common carotid, and left subclavian arteries.
C. Superior Vena Cava
- Is formed by the union of the right and left brachiocephalic veins and returns blood from all structures superior to the diaphragm, except the lungs and heart.
- Descends on the right side of the ascending aorta, receives the azygos vein, and enters the right atrium. Its upper half is in the superior mediastinum, and its lower half is in the middle mediastinum.
D. Pulmonary Trunk
- Arises from the conus arteriosus of the right ventricle, passes obliquely upward and backward across the origin and on the left side of the ascending aorta within the fi brous pericardium, and bifurcates into the right and left pulmonary arteries in the concavity of the aortic arch.