{{Short description|Lower edge of the chest (thorax) formed by the bottom edge of the rib cage}} {{Infobox anatomy | Name = Costal margin | Latin = arcus costalis | Image = Gray115.png | Caption = Anterior surface of sternum and costal cartilages. (The costal margin forms a large upside-down V on the inferior border.) | Image2 = | Caption2 = | System = }} The '''costal margin''', also known as the '''costal arch''',<ref>{{Cite journal|last1=Talucci|first1=R. C.|last2=Webb|first2=W. R.|date=March 1983|title=Costal chondritis: the costal arch|journal=The Annals of Thoracic Surgery|volume=35|issue=3|pages=318–321|doi=10.1016/s0003-4975(10)61566-4|issn=0003-4975|pmid=6830368|doi-access=free}}</ref> is the lower edge of the chest (thorax) formed by the bottom edge of the rib cage.
== Structure == 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.<ref name=":2">{{Citation|last=McGee|first=Steven|title=Chapter 33 - Chronic Obstructive Lung Disease|date=2018-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323392761000330|work=Evidence-Based Physical Diagnosis (Fourth Edition)|pages=285–290.e2|editor-last=McGee|editor-first=Steven|place=Philadelphia|publisher=Elsevier|language=en|isbn=978-0-323-39276-1|access-date=2021-01-04}}</ref>
The thoracic diaphragm attaches to the costal margin.<ref>{{Citation|last1=Mack|first1=Savannah M.|title=Lung Anatomy and Aging☆|date=2020-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780128012383116009|work=Reference Module in Biomedical Sciences|publisher=Elsevier|language=en|isbn=978-0-12-801238-3|access-date=2021-01-04|last2=Wu|first2=Ching-Wen|last3=Zhang|first3=Chuanzhen|last4=Richard Harding|last5=Pinkerton|first5=Kent E.}}</ref>
The '''costal angle''' is the angle between the left and right costal margins where they join the sternum.<ref name=":2" />
== Function == The costal margins somewhat protect the higher abdominal organs, such as the liver.<ref name=":0" /><ref name=":1">{{Citation|last=McGee|first=Steven|title=Chapter 51 - Palpation and Percussion of the Abdomen|date=2018-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323392761000512|work=Evidence-Based Physical Diagnosis (Fourth Edition)|pages=433–444.e4|editor-last=McGee|editor-first=Steven|place=Philadelphia|publisher=Elsevier|language=en|isbn=978-0-323-39276-1|access-date=2021-01-04}}</ref>
== Clinical significance == The costal margin may be used for tissue harvesting of cartilage for use elsewhere in the body, such as to treat microtia.<ref name=":0">{{Citation|last1=Szpalski|first1=C.|title=6.621 - Biomaterials and Their Application in Craniomaxillofacial Surgery|date=2011-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780080552941002191|work=Comprehensive Biomaterials|pages=325–341|editor-last=Ducheyne|editor-first=Paul|place=Oxford|publisher=Elsevier|language=en|isbn=978-0-08-055294-1|access-date=2021-01-04|last2=McRae|first2=M.|last3=Rogers|first3=G. F.|last4=Bumgardner|first4=J. D.|last5=Warren|first5=S. M.}}</ref>
Different abdominal organs may be palpated just below the costal margin, such as the liver on the right side of the body.<ref name=":1" />
Pain across the costal margin is most commonly caused by costochondritis.<ref>{{Citation|last1=Suresh|first1=Santhanam|title=Chapter 16 - Chronic Pain Management in Children|date=2008-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323041843500194|work=Raj's Practical Management of Pain (Fourth Edition)|pages=343–365|editor-last=Benzon|editor-first=Honorio T.|place=Philadelphia|publisher=Mosby|language=en|isbn=978-0-323-04184-3|access-date=2021-01-04|last2=McClain|first2=Brenda C.|last3=Tarbell|first3=Sally|editor2-last=Rathmell|editor2-first=James P.|editor3-last=Wu|editor3-first=Christopher L.|editor4-last=Turk|editor4-first=Dennis C.}}</ref>
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.<ref name=":2" />
== References == <references />
==External links== * {{SUNYAnatomyFigs|35|01|03}}—"Bony landmarks of the abdomen" * {{UMichAtlas|abdo_wall60}}
{{Bones of torso}} {{Authority control}}
Category:Bones of the thorax