![]() ![]() long, and is placed in front of the transverse process of the lower of the two vertebræ with which the head articulates. The neck is the flattened portion which extends lateralward from the head it is about 2.5 cm. ![]() The head is marked by a kidney-shaped articular surface, divided by a horizontal crest into two facets for articulation with the depression formed on the bodies of two adjacent thoracic vertebræ the upper facet is the smaller to the crest is attached the interarticular ligament. Posterior Extremity.The posterior or vertebral extremity presents for examination a head, neck, and tubercle. ![]() 122, 123).≺ rib from the middle of the series should be taken in order to study the common characteristics of these bones.Įach rib has two extremities, a posterior or vertebral, and an anterior or sternal, and an intervening portionthe body or shaft. In breadth they decrease from above downward in the upper ten the greatest breadth is at the sternal extremity.Ĭommon Characteristics of the Ribs (Figs. ![]() The ribs increase in length from the first to the seventh, below which they diminish to the twelfth. The length of each space corresponds to that of the adjacent ribs and their cartilages the breadth is greater in front than behind, and between the upper than the lower ribs. The ribs are situated one below the other in such a manner that spaces called intercostal spaces are left between them. The ribs vary in their direction, the upper ones being less oblique than the lower the obliquity reaches its maximum at the ninth rib, and gradually decreases from that rib to the twelfth. (* 21 The remaining five are false ribs of these, the first three have their cartilages attached to the cartilage of the rib above ( vertebro-chondral): the last two are free at their anterior extremities and are termed floating or vertebral ribs. 115) they are called true or vertebro-sternal ribs. The first seven are connected behind with the vertebral column, and in front, through the intervention of the costal cartilages, with the sternum (Fig. They are twelve in number on either side but this number may be increased by the development of a cervical or lumbar rib, or may be diminished to eleven. (Costæ)The ribs are elastic arches of bone, which form a large part of the thoracic skeleton. ![]()
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