Sternal angle

The sternal angle (also known as the angle of Lewis, angle of Louis, angle of Ludovic, or manubriosternal junction) is the projecting angle formed between the manubrium and body of a sternum at their junction at the manubriosternal joint.

The sternal angle is a palpable and visible landmark in surface anatomy, presenting as either a slight body ridge or depression upon the upper chest wall which corresponds to the underlying manubriosternal joint. The sternal angle is palpable and often visible in young people.

The sternal angle corresponds to the level of the 2nd costal cartilage on either side, and the level between the fourth and fifth thoracic vertebra. The sternal angle is used to define the transverse thoracic plane which represents the imaginary boundary between the superior and inferior mediastinum. It is also used to identify the second rib during physical examination and then the rest of the ribs by counting.