Sternum


	Latin
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	GrayPage	119
	Image	Gray115png
	Caption	Anterior surface of Sternum and Costal Cartilages
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	Caption2	Posterior surface of sternum
	Origins
	Insertions
	Articulations
	MeshName	Sternum
	MeshNumber	A02835232904766
	DorlandsPre	s_23
	DorlandsSuf	12758288

Sternum or '''breastbone''' is a long, flat Bone located in the center of the Thorax (chest). It connects to the Rib Bones via Cartilage , forming the Rib Cage with them, and thus helps to protect the Lungs and Heart from physical Trauma .

The sternum is sometimes cut open (a Sternotomy ) to gain access to the thoracic contents when performing cardiothoracic surgery.

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. It consists of three parts, named from above downward:

Manubrium

Body Of Sternum

Xiphoid Process

In early life the body consists of four segments or ''sternebrœ.''

In its natural position the inclination of the bone is oblique from above, downward and forward. 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.

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 .

FRACTURES OF THE STERNUM

Fractures of the sternum are not common. However they may result from trauma, such as when a driver's chest is forced into the Steering Column in an accident. 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 .

REFERENCES

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

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Sternum