Costal margin
Lower edge of the chest (thorax) formed by the bottom edge of the rib cage
The costal margin, also known as the costal arch, is the lower edge of the chest (thorax) formed by the bottom edge of the rib cage.
01Structure
The costal margin is the medial margin formed by the cartilages of the seventh to tenth ribs. It attaches to the body and xiphoid process of the sternum.
The thoracic diaphragm attaches to the costal margin.
The costal angle is the angle between the left and right costal margins where they join the sternum.
02Function
The costal margins somewhat protect the higher abdominal organs, such as the liver.
03Clinical significance
The costal margin may be used for tissue harvesting of cartilage for use elsewhere in the body, such as to treat microtia.
Different abdominal organs may be palpated just below the costal margin, such as the liver on the right side of the body.
Pain across the costal margin is most commonly caused by costochondritis.
The costal paradox, also known as Hoover's sign and the costal margin paradox, is a sign where the costal angle decreases upon inspiration rather than increasing, indicating chronic obstructive pulmonary disease.
Sources and credits
This article is adapted from the Wikipedia article “Costal margin”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Gray115.png by Henry Vandyke Carter, Public domain
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