Editing Rib (section)

==Human anatomy==
===Rib details===
Human ribs are [[flat bone]]s that form part of the [[rib cage]] to help protect internal organs. Humans usually have 24 ribs, in 12 pairs.<ref name=":0">{{Citation|last1=Sly|first1=Peter D.|title=Chapter 7 - Applied Clinical Respiratory Physiology|date=2008-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323040488500116|work=Pediatric Respiratory Medicine (Second Edition)|pages=73–88|editor-last=Taussig|editor-first=Lynn M.|place=Philadelphia|publisher=Mosby|language=en|doi=10.1016/b978-032304048-8.50011-6|isbn=978-0-323-04048-8|access-date=2020-11-03|last2=Collins|first2=Rachel A.|editor2-last=Landau|editor2-first=Louis I.|url-access=subscription}}</ref> 1 in 500 people have an extra rib known as a [[cervical rib]]. People may have a cervical rib on the right, left or both sides.<ref>{{cite journal |last1=Oner |first1=Zulal |last2=Oner |first2=Serkan |last3=Sahin |first3=Necati Emre |last4=Cay |first4=Mahmut |title=Evaluation of congenital rib anomalies with multi-detector computed tomography in the Turkish population |journal=Folia Morphologica |date=26 January 2023 |doi=10.5603/FM.a2023.0006|pmid=36794687 |s2cid=256899032 |doi-access=free }}</ref>  All are attached at the back to the [[thoracic vertebrae]] and are numbered from 1 to 12 according to the vertebrae to which they attach. The first rib is attached to thoracic vertebra 1 (T1). At the front of the body, most of the ribs are joined by [[costal cartilage]] to the [[sternum]]. Ribs connect to vertebrae at the [[costovertebral joints]].<ref>{{cite book |last1=Moore |first1=Keith L. |last2=Dalley |first2=Arthur F. |last3=Agur |first3=Anne M. R. |title=Clinically Oriented Anatomy |date=2018 |publisher=Wolters Kluwer |location=Philadelphia |isbn=9781496347213 |pages=293–297 |edition=8th}}</ref>

The parts of a rib includes the head, neck, body (or ''shaft''), tubercle, and angle. 

The '''head of the rib''' lies next to a vertebra. The ribs connect to the vertebrae with two costovertebral joints, one on the head and one on the neck. The head of the rib has a superior and an inferior articulating region, separated by a crest. These articulate with the [[superior costal facet|superior]] and [[inferior costal facet]]s on the connecting vertebrae.<ref name="Netter">{{cite book |last1=Netter |first1=Frank |title=Atlas of human anatomy |date=2014 |publisher=Saunders |isbn=9781455704187 |pages=183–184 |edition=Sixth}}</ref> The crest gives attachment to the [[intra-articular ligament of head of rib|intra-articulate ligament]] that joins the rib to the vertebra of the same number, at the [[intervertebral disc]]. Another [[ligament]], the [[radiate ligament of head of rib|radiate ligament]] joins the head of the rib to both the body of the upper vertebra and to the body of the lower vertebra. The smaller middle part of the ligament connects to the intervertebral disc. This [[plane joint]] is known as the [[articulation of head of rib|articulation of the head of the rib]].

The other costovertebral joint is that between the tubercle on the neck and the transverse process of the corresponding thoracic vertebra, known as the [[costotransverse joint]]. The [[superior costotransverse ligament]] attaches from the non-articular facet of the tubercle to the transverse process of the vertebra.

The '''neck of the rib''' is a flattened part that extends laterally from the head. The neck is about 3&nbsp;cm long. Its anterior surface is flat and smooth, whilst its posterior is perforated by numerous foramina and its surface rough, to give attachment to the ligament of the neck. Its upper border presents a rough crest (''crista colli costae'') for the attachment of the anterior [[costotransverse ligament]]; its lower border is rounded. 

A '''tubercle of rib''' on the posterior surface of the neck of the rib, has two facets (surfaces) one articulating and one non-articulating. The articular facet, is small and oval and is the lower and more medial of the two, and connects to the [[transverse costal facet]] on the thoracic vertebra of the same rib number.<ref name="Netter" /> The transverse costal facet is on the end of the transverse process of the lower of the two vertebrae to which the head is connected. The non-articular portion is a rough elevation and affords attachment to the ligament of the tubercle. The tubercle is much more prominent in the upper ribs than in the lower ribs.


===Rib cage===
{{Main|Rib cage}}
[[Image:Ribs labeled.png|thumb|left|200px|[[X-ray]] image of human chest, with ribs labelled]]
The first seven sets of ribs, known as "[[true ribs]]", are attached to the [[sternum]] by the [[costal cartilage]]s. The first rib is unique and easier to distinguish than other ribs. It is a short, flat, C-shaped bone, and attaches to the manubrium.<ref>{{Citation|last1=Sly|first1=Peter D.|title=Chapter 7 - Applied Clinical Respiratory Physiology|date=2008-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323040488500116|work=Pediatric Respiratory Medicine (Second Edition)|pages=73–88|editor-last=Taussig|editor-first=Lynn M.|place=Philadelphia|publisher=Mosby|language=en|doi=10.1016/b978-032304048-8.50011-6|isbn=978-0-323-04048-8|access-date=2020-11-03|last2=Collins|first2=Rachel A.|editor2-last=Landau|editor2-first=Louis I.|url-access=subscription}}</ref> The vertebral attachment can be found just below the [[neck]] at the first thoracic vertebra, and the majority of this bone can be found above the level of the [[clavicle]]. Ribs 2 through 7 then become longer and less curved as they progress downwards.<ref name="Saladin, K. S. 2010">Saladin, K. S. (2010). Anatomy and Physiology: The Unity of Form and Function (5th ed.). New York, NY: McGraw-Hill.</ref> The following five sets are known as "[[false ribs]]", three of these sharing a common cartilaginous connection to the sternum, while the last two (eleventh and twelfth ribs) are termed [[floating rib]]s.<ref name=":0" /> They are attached to the [[vertebrae]] only, and not to the sternum or cartilage coming off of the sternum. 

In general, human ribs increase in length from ribs 1 through 7 and decrease in length again through rib 12.  Along with this change in size, the ribs become progressively oblique (slanted) from ribs 1 through 9, then less slanted through rib 12.<ref name="Saladin, K. S. 2010"/> 

The rib cage is separated from the lower abdomen by the [[thoracic diaphragm]] which controls breathing. When the diaphragm contracts, the thoracic cavity is expanded, reducing intra-thoracic pressure and drawing air into the lungs. This happens through one of two actions (or a mix of the two): when the lower ribs the diaphragm connects to are stabilized by muscles and the central tendon is mobile, when the muscle contracts the central tendon is drawn down, compressing the cavity underneath and expanding the thoracic cavity downward. When the central tendon is stabilized and the lower ribs are mobile, a contraction of the diaphragm elevates the ribs, which works in conjunction with other muscles to expand the thoracic indent upward.