Bone: Sternum
Thoracic cage
Posterior surface of sternum.
Gray's	subject #27 119
MeSH	Sternum
Dorlands / Elsevier	s_23/12758288

The sternum (from Greek στέρνον, sternon, "chest" or breastbone) is a long, flat bone located in the center of the thorax (chest). Introduction ( classes Long bones body or Diaphysis Medullary canal Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce The chest is a part of the Anatomy of humans and various other animals sometimes referred to as the Thorax. It connects to the rib bones via cartilage, forming the rib cage with them, and thus helps to protect the lungs, heart and major blood vessels from physical trauma. In Vertebrate Anatomy, ribs ( Latin costae) are the long curved Bones which form the ribcage. 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 human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic (chest cavity and supports the pectoral lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic Treatment of physical trauma is described here and in First aid.

The sternum is sometimes cut open (a median sternotomy) to gain access to the thoracic contents when performing cardiothoracic surgery. Median sternotomy is a type of Surgical procedure in which a vertical inline Incision is made along the Sternum, after which the sternum itself is divided

Overview

The sternum is an elongated, flattened bone, forming the middle portion of the anterior wall of the thorax. Its upper end supports the clavicles (Collar bones), and its margins articulate with the cartilages of the first seven pairs of ribs. Its top is also connected to the Sternocleidomastoid muscle. In Human Anatomy, the sternocleidomastoid (pronounced /ˌstɚ It consists of three parts, from above downward:

• Manubrium
• Body of sternum (gladiolus)
• Xiphoid process

In its natural position, the inclination of the bone is oblique from above, downward and forward. The manubrium (from Latin manubrĭum, "a handle" or manubrium sterni is the broad upper part of the Sternum. The body of the Sternum ( gladiolus) considerably lengthier narrower and thinner than the Manubrium, attains its greatest breadth close to the lower end The xiphoid process, also known as the xiphisternum is a small cartilaginous extension to the lower part of the Sternum which is usually It is slightly convex in front and concave behind; broad above, becoming narrowed at the point where the manubrium joins the body, after which it again widens a little to below the middle of the body, and then narrows to its lower extremity. Its average length in the adult is about 17 cm, and is rather longer in the male than in the female. A centimetre ( American spelling: centimeter, symbol cm) is a unit of Length in the Metric system, equal to one hundredth

In early life its body is divided in four segments, called sternebrœ (singular: sternebra).

Structure

The sternum is composed of highly vascular cancellous tissue, covered by a thin layer of compact bone which is thickest in the manubrium between the articular facets for the clavicles.

Articulations

The sternum articulates on either side with the clavicle and upper seven costal cartilages. 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

Fractures of the sternum

Main article: Sternal fracture

Fractures of the sternum are rather uncommon. A sternal fracture is a fracture of the Sternum (the breastbone located in the center of the Chest. A sternal fracture is a fracture of the Sternum (the breastbone located in the center of the Chest. However, they may result from trauma, such as when a driver's chest is forced into the steering column of a car in a car accident. The automotive steering column is a device intended primarily for connecting the Steering wheel to the steering mechanism by transferring the driver's input torque from A fracture of the sternum is usually a comminuted fracture, meaning it is broken into pieces. The most common site of sternal fractures is at the sternal angle. The sternal angle is the angle formed by the junction of the Manubrium and the body of the Sternum (the manubriosternal junction) in the form of a secondary

Sternum fractures are frequently associated with underlying injuries such as pulmonary contusions, or bruised lung tissue. A pulmonary contusion (or lung contusion) is a contusion ( Bruise) of the Lung, caused by Chest trauma. ^[1]

Additional images

Anterior surface of sternum and costal cartilages. 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

References

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.

• Clinically Oriented Anatomy, 4th ed. Keith L. Moore and Arthur F. Dalley. pp. 66-68.

See also

• Ossification of sternum
• Bone terminology
• Terms for anatomical location
• Pectus carinatum
• Pectus excavatum