|Lateral border of sternum.|
|Anterior surface of sternum and costal cartilages. (Sternal angle not labeled, but visible at second costal cartilage.)|
|Latin||angulus sterni, angulus sternalis|
|Gray's||subject #27 121|
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). This is also called the manubriosternal joint or Angle of Louis. The sternal angle is a palpable clinical landmark.
It is named after Pierre Charles Alexandre Louis, a French physician of the 19th century, who was one of the first to bring mathematics to medicine, disproving bloodletting as a practice by showing statistically that it did not work.
The sternal angle, which varies around 162 degrees in males, marks the approximate level of the 2nd pair of costal cartilages, which attach to the second ribs, and the level of the intervertebral disc between T4 and T5. The angle also marks a number of other features:
- Boundary between the superior and inferior portion of the mediastinum
- Passage of the thoracic duct from right to left behind esophagus
- Aortic Arch
- Tracheal Bifurcation
- End of the azygos system into SVC
- Ligamentum arteriosum
- Loop of left recurrent laryngeal nerve around aortic arch
- Aortic arch starts and ends
A use mnemonic for what passes through here is "RAT PLLANT"
- Rib 2
- Aortic arch
- Tracheal bifurcation
- Pulmonary trunk
- Ligamentum arteriosum
- Left recurrent laryngeal
- Nerves (Cardiac and Pulmonary plexuses)
- Thoracic duct
A more detailed mnemonic is "PLOT of EARTH PLLANTS"
- Phrenic and Vagus Nerve
- Lymph Nodes
- Oblique fissure of lungs (top of it)
- Esophagus (trending right to left)
- Aortic Arch (bottom of the arch)
- Rib 2, Manubrium-sternal angle, T4(more specifically T4-5 disc)
- Tracheal Bifurcation (Carina: Latin –like keel of boat)
- Pulmonary trunk bifurcation
- L2 : Left Recurrent Laryngeal (Looping under Aorta); Ligamentum Arteriosum: Connects Aortic Arch to Pulmonary. Bifurcation
- Azygous vein arches over the roof of the Rt. Lung and opens in SVC.
- Nerve plexi: Cardiac and Pulmonary Plexus
- Thoracic duct (on its way to drain into the Left Subclavian)
- SVC going down
The vagus nerve turns back.
C6 is found there.
- Dalley, Arthur F.; Moore, Keith L. Clinically Oriented Anatomy. Hagerstown, MD: Lippincott Williams & Wilkins. ISBN 0-7817-5936-6.
- Gray's Anatomy 40th edition. Chapter 54: Chest wall and breast: Churchill Livingstone Elsevier. 2008. p. 922. ISBN 978-0-8089-2371-8.