Sternal angle

The Sternal Angle also known as the Angle of Louis or manubriosternal junction is a notable anatomical landmark in the human body. It is a horizontal ridge on the sternum, marking the junction between the manubrium and the body of the sternum.

Etymology

The term "Angle of Louis" comes from the French physician Antoine Louis who recognized its clinical significance in the 18th century.

Anatomy

The sternal angle is a palpable, transverse projection on the anterior thoracic wall at the level of the second costal cartilage. It is formed by the articulation of the manubrium and the body of the sternum. The sternal angle is at the level of the intervertebral disc between T4 and T5.

Clinical Significance

The sternal angle is an important landmark in the anatomy of the thorax. It is used as a starting point for counting the ribs and intercostal spaces, as the second rib attaches to the sternum at the sternal angle. It also marks the level where the trachea bifurcates into the left and right main bronchi, and where the aorta descends behind the heart.

Related Terms

• Manubrium
• Sternum
• Thorax
• Trachea
• Aorta

See Also

• Thoracic wall
• Intercostal space
• Bronchus