Human rib cage 4029780 215882066 2008-05-30T02:58:10Z EricV89 1475928 Reverted edits by [[Special:Contributions/75.47.250.200|75.47.250.200]] ([[User talk:75.47.250.200|talk]]) to last version by Diligent Terrier {{Infobox Anatomy | Name = {{PAGENAME}} | Latin = | GraySubject = | GrayPage = | Image = Gray112.png | Caption = The human '''rib''' cage. <small>(Source: ''[[Gray's Anatomy|Gray's Anatomy of the Human Body]]'', 20th ed. 1918.)</small> | Image2 = | Caption2 = | Precursor = | System = | Artery = | Vein = | Nerve = | Lymph = | MeshName = | MeshNumber = | DorlandsPre = c_01 | DorlandsSuf = 12204262 | }} The '''human rib cage''' is a part of the [[human skeleton]] within the [[thoracic]] area. A typical human ribcage consists of 24 [[rib]]s, 12 on each side of the [[thoracic cavity]], the [[sternum]] and the 12 [[thoracic vertebra]]e in both males and females. ==Number of ribs== The number of ribs was noted by the [[Flemish people|Flemish]] [[anatomist]] [[Vesalius]] in [[1543]], setting off a wave of controversy, as it was traditionally assumed from the Biblical story of [[Adam and Eve]] that men's ribs would number one fewer than women's. (''[[De humani corporis fabrica]]''<ref>{{cite web |url=http://vesalius.northwestern.edu/ixmlquery/hilight?parm1=chapters/FA.1.19&keyword=rib&scrollpoint=FA.1.19.07& |title=Chapter 19 On the Bones of the Thorax |accessdate=2007-08-23 |format= |work=}}</ref>) A small proportion of people have one pair more or fewer but this is unrelated to sex. Humans have seven rows of [[true ribs]], each with its own connection to the sternum. Humans also have three rows of [[false ribs]] which connect to the ones above it. The last two rows, which don't connect to the sternum, are called [[floating ribs]]. In the front, the upper 7 ribs are attached to the sternum by means of costal [[cartilage]]. Due to their elasticity they allow movement when inhaling and exhaling. The 8th, 9th, and 10th ribs join with the costal cartilages of the ribs above. The 11th and 12th ribs are known as floating ribs, as they do not have any anterior connection. ==Function== The Human rib cage is a component of the human [[respiratory system]]. It encloses the [[thoracic cavity]], which contains the lungs. An inhalation is accomplished when the muscular [[diaphragm]], at the floor of the thoracic cavity, contracts and flattens, while contraction of [[intercostal muscles]] lift the rib cage up and out. These actions produce an increase in volume, and a resulting partial vacuum, or negative pressure, in the thoracic cavity, resulting in [[atmospheric pressure]] pushing air into the lungs, inflating them. An exhalation results when the diaphragm and intercostal muscles relax, and elastic recoil of the rib cage and lungs expels the air. ==Rib anatomy== [[Image:Gray122.png|thumb|right|300px]] The human [[rib]] parts: *The [[Head of rib|head]] is the end of a [[rib]] closest to the [[vertebral column]]. *The [[Neck of rib|neck]] is the flattened portion which extends lateralward from the head. *The [[Tubercle (rib)|tubercle]] is an eminence on the posterior surface. *The [[Angle (rib)|angle]] is a bending part. *The [[Costal groove]] is a groove between the ridge of the internal surface of the [[rib]] and the inferior border. ==Types of ribs== [[Image:Gray115.png|thumb|left|Anterior surface of sternum and costal cartilages.]] * The first seven pairs of ribs are connected to the [[sternum]] in front and are known as ''true ribs'' or ''vertebrosternal ribs'' (''costae verae'', I-VII). * The eighth, ninth, and tenth attached in front to the [[cartilage|cartilaginous]] portion of the next rib above and are known as ''false ribs'' or ''vertebrochondral ribs'' (''costae spuriae'', VIII-X). * The lower two, that is the eleventh and twelfth, are not attached in front and are called ''[[floating rib]]s'' or ''vertebral ribs'' (''costae fluitantes'', XI-XII). * In some humans, the rib remnant of the 7th [[Cervical vertebrae|cervical vertebra]] on one or both sides is replaced by a free extra rib called a [[cervical rib]], which can cause problems in the nerves going to the arm. The spaces between the ribs are known as [[intercostal spaces]]; they contain the intercostal [[muscle]]s, [[nerve]]s, and [[artery|arteries]]. The rib cage allows for [[breath]]ing due to its elasticity. ===Atypical ribs=== The atypical ribs are the 1st, 2nd, and 10th to 12th. * The first rib has a shaft that is wide and nearly horizontal, and has the sharpest curve of the seven true ribs. Its head has a single facet to articulate with the first thoracic vertebra ([[thoracic vertebrae|T1]]). It also has two grooves for the subclavian vessels, which are separated by the scalene tubercle. * The second rib is thinner, less curved, and longer than the first rib. It has two facets to articulate with T2 and T1, and a tubercle for muscles to attach to. * The 10th to 12th ribs have only one facet on their head; the 11th and 12th ribs are short with no necks or tubercles and terminate in the abdominal wall before fusing with the [[costal cartilage]]s. ==Medical conditions== * [[Rib fracture]]s can occur. These most frequently affect the middle ribs. When several ribs are injured, this can result in a [[flail chest]]. * A [[bifid rib]] is a [[congenital]] [[abnormality]] occurring in about 1.2% of the population. * Pectus deformities: [[Pectus excavatum]] also called "sunken chest"; and [[Pectus carinatum]], also called "pigeon chest". ==Additional images== <gallery> Image:Gray124.png Image:Gray125.png Image:Gray126.png Image:Gray127.png Image:Gray128.png Image:Ribs labeled.png|[[X-ray]] image of human chest, with ribs labeled. </gallery> ==See also== *[[Cervical rib]] *[[Bone#Terminology|Bone terminology]] *[[Terms for anatomical location]] *[http://vesalius.northwestern.edu/index.html De Humani Corporis Fabrica] Online English translation of Vesalius' books on human anatomy. *[[Rib removal]] *[[Costovertebral articulations]] ==References== <references/> *Clinically Oriented Anatomy, 4th ed. Keith L. Moore and Robert F. Dalley. pp. 62-64 *Tortora GJ and Derrickson B. PRINCIPLES OF ANATOMY PHYSIOLOGY, 11th ED. John Wiley and Sons, 2006. ISBN-10: 0-471-68934-3 {{Spine}} {{human anatomical features}} [[Category:Human anatomy]] [[Category:Thorax]] [[Category:Flat bones]] [[bg:Ребро]] [[da:Ribben]] [[de:Rippe]] [[fr:Côte (anatomie)]] [[he:צלעות]] [[lt:Šonkaulis]] [[nl:Ribbenkast]] [[ja:肋骨]] [[no:Ribben]] [[pl:żebra (anatomia)]] [[pt:Costela]] [[sv:Bröstkorg]] [[tr:Göğüs kafesi]]