- First rib
Infobox Bone
Name = First rib
Latin = costa prima
GraySubject = 28
GrayPage = 125
Caption = First rib.
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DorlandsPre = c_58
DorlandsSuf = 12262718
The first rib is the most curved and usually the shortest of all theribs ; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward.The "head" is small, rounded, and possesses only a single articular facet, for articulation with the body of the first
thoracic vertebra .The "neck" is narrow and rounded.
The "tubercle", thick and prominent, is placed on the outer border.
There is no "angle", but at the "tubercle" the rib is slightly bent, with the convexity upward, so that the head of the bone is directed downward.
The upper surface of the body is marked by two shallow grooves, separated from each other by a slight ridge prolonged internally into a tubercle, the
scalene tubercle , for the attachment of theScalenus anterior ; the "anterior groove" transmits thesubclavian vein , the "posterior "thesubclavian artery and the lowest trunk of thebrachial plexus . Behind the posterior groove is a rough area for the attachment of theScalenus medius .The "under surface" is smooth, and destitute of a costal groove.
The "outer border" is convex, thick, and rounded, and at its posterior part gives attachment to the first digitation of the
Serratus anterior .The "inner border" is concave, thin, and sharp, and marked about its center by the scalene tubercle.
The "anterior extremity" is larger and thicker than that of any of the other ribs.
ee also
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Subclavius muscle
=AdditionalExternal links
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