Sternal angle

The sternal angle forms an angle of about 162° in males.{{cite book|editor=Susan Standring |editor2=Neil R. Borley |chapter=Chapter 54: Chest wall and breast |title=Gray's anatomy : the anatomical basis of clinical practice |pages=922 |date=2008|publisher=Churchill Livingstone|location=London|isbn=978-0-8089-2371-8|edition=40th|ref={{harvid|Gray's Anatomy|2008}}|display-editors=etal}}

It marks the approximate level of the 2nd pair of costal cartilages,{{Rp|page=319}} (sources differ) the level of the intervertebral disc between thoracic vertebra T4-T5{{cite book |last1=Wilson |first1=Herbert H. Srebnik ; illustrations by Genevieve M. |title=Concepts in anatomy |date=2002 |publisher=Kluwer Academic Publishers |isbn=0792375394 |location=Boston |pages=70}}{{Rp|page=319}} or the lower border of the thoracic vertebra T4,{{Cite book |last=Sinnatamby |first=Chummy S. |title=Last's Anatomy |vauthors= |publisher= |year=2011 |isbn=978-0-7295-3752-0 |edition=12th |pages=}}{{Rp|page=218}} and the space between the spinous processes of thoracic vertebrae T3-T4.{{Rp|page=319}} The horizontal plane that passes through the sternal angle and the articular disc between the 4th and 5th thoracic vertebrae represents the imaginary boundary between the superior mediastinum and inferior mediastinum.{{Citation needed|date=June 2023}}

It is located approximately 7 cm inferior to the superior margin of the manubrium.{{Citation needed|date=June 2023}}

The sternal angle is used in the definition of the thoracic plane.{{Citation needed|date=June 2023}}

The angle also marks the level of a number of features:

:* Boundary between the superior and inferior portion of the mediastinum{{Citation needed|date=June 2023}}

:* Passage of the thoracic duct from right to left behind esophagus{{Citation needed|date=June 2023}}

:* Tracheal bifurcation.{{Rp|page=|pages=387, 1039, 1060}} The carina of the trachea is thus, present here. It is deep to the sternal angle.

:* The bifurcation of the pulmonary trunk{{Rp|page=336}}

:* The superior limit of the fibrous pericardium surrounding the ascending aorta{{Rp|page=350}}

:* Termination of the azygos vein into the superior vena cava{{Rp|page=193}}

:* Ligamentum arteriosum{{Citation needed|date=June 2023}}

:* Loop of left recurrent laryngeal nerve around aortic arch{{Citation needed|date=June 2023}}

:* The beginning and end of the aortic arch{{Rp|page=383}}{{Rp|page=190}}

The sternal angle is the most frequent site of sternal fracture among elderly people.{{Rp|page=303}}

The sternal angle marks the point at which the costal cartilage of either second rib articulates with the sternum. During physical examinations, the readily palpated sternal angle is thus used as a landmark to identify the 2nd rib, and by extension, by counting, also the remaining ribs. Meanwhile, the first rib cannot be used for this purpose because it cannot be palpated.{{Rp|page=321}} Counting ribs is essential attempting to make a thoracic incision; an incision at the first or second rib interspace can result in damage to large, important blood vessels and the brachial plexus. Identification of the second rib and thus the second intercostal space inferiorly is useful when auscultating heart sounds. The optimal location for auscultation of the aortic valve is generally the right second intercostal space, whereas the optimal location for auscultation of the pulmonic valve is generally the left second intercostal space.{{Citation needed|date=June 2023}}

The sternal angle is used as the starting point in physical examinations of the heart since the sternal angle is located 5 cm superior to the right atrium.{{Citation needed|date=June 2023}}

The sternal angle is also called the angle of Louis, but the reason for that name was lost. Once thought to be after Antoine Louis or Wilhelm Friedrich von Ludwig, it is now believed to be after Pierre Charles Alexandre Louis.{{cite journal |url=http://eurjanat.com/data/pdf/eja.130056ld.pdf |journal=Eur. J. Anat. |volume=17 |issue=3 |pages=190–192 |date=2013 |title=The "Angle of Louis" |author=Alberto Coscione |author2=L. Dixon |author3=H. Ellis }}

• Thoracic plane
• List of medical mnemonics

• {{SUNYAnatomyLabs|18|st|02|12}} - "Thoracic Wall: Bones"

{{Bones of torso}}

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{{DEFAULTSORT:Sternal Angle}}

Category:Bones of the thorax