| Costal cartilages | |
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| Sternocostal and interchondral articulations. Anterior view. | |
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| Anterior surface of sternum and costal cartilages. The sternum (from Greek στέρνον sternon, "chest" or breastbone) is a long flat Bone located in the center of the thorax (chest | |
| Latin | cartilagines costales |
| Gray's | subject #29 127 |
| Dorlands/Elsevier | c_12/12217117 |
The costal cartilages are bars of hyaline cartilage which serve to prolong the ribs forward and contribute very materially to the elasticity of the walls of the thorax. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Introduction ( classes Long bones body or Diaphysis Medullary canal Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group The term hyaline (from the Greek ὕαλος ‘glassy’ literally refers to a substance with a glass-like appearance Cartilage is a type of dense Connective tissue. It is composed of specialized cells called chondrocytes that produce a large amount of extracellular matrix The thorax is a division of an Animal 's body that lies between the head and the Abdomen.
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Differences from 1-12
The first seven pairs are connected with the sternum; 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 the abdomen. The sternum (from Greek στέρνον sternon, "chest" or breastbone) is a long flat Bone located in the center of the thorax (chest In Vertebrates such as Mammals the abdomen (belly constitutes the part of the body between the Thorax (chest and Pelvis.
Like the ribs, the costal cartilages vary in their length, 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, 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.
Structure
Each costal cartilage presents two surfaces, two borders, and two extremities.
Surfaces
The anterior surface is convex, and looks forward and upward: that of the first gives attachment to the costoclavicular ligament and the Subclavius muscle; those of the first six or seven at their sternal ends, to the Pectoralis major. The costoclavicular ligament ( rhomboid ligament) is short flat strong and rhomboid in form The Subclavius is a small triangular muscle placed between the Clavicle and the First rib. The Pectoralis major (popularly known as pecs) is a thick fan-shaped muscle situated at the upper front ( Anterior) of the Chest wall The others are covered by, and give partial attachment to, some of the flat muscles of the abdomen.
The posterior surface is concave, and directed backward and downward; that of the first gives attachment to the Sternothyroideus, those of the third to the sixth inclusive to the Transversus thoracis, and the six or seven inferior ones to the Transversus abdominis and the diaphragm. The Sternothyreoideus (or Sternothyroid muscle) is shorter and wider than the Sternohyoideus, beneath which it is situated The tranversus thoracis lies internal to the Thoracic cage, anteriorly The transversus abdominis muscle, also known as the transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior and lateral Abdominal For other types of diaphragm see Diaphragm. In the Anatomy of Mammals the thoracic diaphragm is a sheet of Muscle
Borders
Of the two borders the superior is concave, the inferior convex; they afford attachment to the Intercostales interni: the upper border of the sixth gives attachment also to the Pectoralis major. The Intercostales interni ( Internal intercostals) are eleven in number on either side The Pectoralis major (popularly known as pecs) is a thick fan-shaped muscle situated at the upper front ( Anterior) of the Chest wall
The inferior 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 respectively with facets on slight projections from the upper borders of the seventh, eighth, ninth, and tenth cartilages.
Extremities
The lateral end of each cartilage is continuous with the osseous 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.
In old age the costal cartilages are prone to undergo superficial ossification.
External links
This article was originally based on an entry from a public domain edition of Gray's Anatomy. The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened is an English-language Human anatomy Textbook As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
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