What is where is the sternal angle?

The sternal angle, also known as the Angle of Louis, is the point where the body of the sternum (breastbone) articulates with the manubrium (upper part of the sternum). It is located in the center of the chest, at the level of the second rib. The sternal angle is an important anatomical landmark as it marks the level of important structures in the mediastinum, such as the aortic arch, the tracheal bifurcation, and the beginning and end of the pericardium. Clinical examination of the sternal angle can help diagnose conditions such as aortic aneurysms, lung cancer, and pericarditis.