Complex sentence: The sternal angle or angle of Louis, from the Latin "angulus Ludovici" is the anterior angle formed by the junction of the manubrium and the body of the sternum (the manubriosternal junction) in the form of a secondary cartilaginous joint (symphysis).
Split into simpler sentences: The sternal angle (also known as the angle of Louis or manubriosternal junction), refers to the angle formed by the junction of the manubrium and the body of the sternum. The angle is in the form of a secondary cartilaginous joint (symphysis).