| Costal cartilage | |
|---|---|
 Position of the costal cartilages (shown in red). | |
 Sternocostal andinterchondral articulations. Anterior view. | |
| Details | |
| Identifiers | |
| Latin | cartilagines costales |
| Greek | costo condrio |
| MeSH | D066186 |
| TA98 | A02.3.01.005 |
| TA2 | 1140,1139 |
| FMA | 7591 |
| Anatomical terminology | |
Costal cartilage, also known asrib cartilage, are bars ofhyaline cartilage that serve to prolong theribs forward and contribute to the elasticity of the walls of thethorax.[1] Costal cartilage is only found at the anterior ends of the ribs, providing medial extension.
The first seven pairs are connected with thesternum; the next three are each articulated with the lower border of the cartilage of the preceding rib; the last two have pointed extremities, which end in the wall of theabdomen.[2]
Like the ribs, the costal cartilages vary in theirlength,breadth, and direction. They increase in length from the first to the seventh, then gradually decrease to the twelfth.
Their breadth, as well as that of the intervals between them, diminishes from the first to the last. They are broad at their attachments to the ribs, and taper toward their sternal extremities, excepting the first two, which are of the same breadth throughout, and the sixth, seventh, and eighth, which are enlarged where their margins are in contact.
They also vary in direction: the first descends a little to the sternum, the second is horizontal, the third ascends slightly, while the others are angular, following the course of the ribs for a short distance, and then ascending to the sternum or preceding cartilage.
Each costal cartilage presents two surfaces, two borders, and two extremities.
Theanterior surface is convex, and looks forward and upward: that of the first gives attachment to thecostoclavicular ligament and thesubclavius muscle; those of the first six or seven at their sternal ends, to thepectoralis major. The others are covered by, and give partial attachment to, some of the flat muscles of the abdomen.
Theposterior surface is concave, and directed backward and downward; that of the first gives attachment to thesternothyroideus, those of the third to the sixth inclusive to thetransversus thoracis muscle, and the six or seven inferior ones to thetransversus abdominis muscle and thediaphragm.
Of the two borders thesuperior is concave, the inferior convex; they afford attachment to theinternal intercostals: the upper border of the sixth gives attachment also to thepectoralis major.
Theinferior borders of the sixth, seventh, eighth, and ninth cartilages present heel-like projections at the points of greatest convexity. These projections carry smooth oblong facets which articulate with facets on slight projections from the upper borders of the seventh, eighth, ninth, and tenth cartilages, respectively.
Theinterchondral articulations are thejoints formed between thecostal cartilages of theribs. The contiguous borders of the sixth, seventh, and eighth, and sometimes those of the ninth and tenth,costal cartilages articulate with each other by small, smooth, oblong facets. Each articulation is enclosed in a thinarticular capsule, lined bysynovial membrane and strengthenedlaterally and medially byligamentous fibers (interchondral ligaments) which pass from one cartilage to the other. Sometimes the fifth costal cartilages, more rarely the ninth and tenth, articulate by theirlower borders with the adjoining cartilages by small oval facets; more frequently the connection is by a few ligamentous fibers.
The lateral end of each cartilage is continuous with theosseous tissue of the rib to which it belongs.
The medial end of the first is continuous with the sternum; the medial ends of the six succeeding ones are rounded and are received into shallow concavities on the lateral margins of the sternum.
The medial ends of the eighth, ninth, and tenth costal cartilages are pointed, and are connected each with the cartilage immediately above.
Those of the eleventh and twelfth are pointed and free.
Inold age, the costal cartilages are prone to superficialossification, particularly in women with age of 50 years and over.[3]
Incostochondritis andTietze syndrome, inflammation of the costal cartilage occurs.[4] This is a common cause ofchest pain.[5]
Severe trauma may lead tofracture of the costal cartilage.[6] Such injuries often go unnoticed duringx-ray scans, but can be diagnosed withCT scans.[6]Surgery is typically used to fix the costal cartilage back onto either the rib or sternum.[6]
Costal cartilage may beharvested for reparative use elsewhere in the body.[1][7] Whilst this is typically conducted using ageneral anaesthetic, IVsedation can also be used.[7] The procedure presents a minor risk ofpleural tear.[7]
This article incorporates text in thepublic domain frompage 127 of the 20th edition ofGray's Anatomy(1918)
