A manual of anatomy . 8 OSTEOLOGY the shortest. The curvature is not uniform but varies in the differentregions and gives the peculiar shape of the thorax. From the tuber-cle the rib proceed first laterally and at a variable distance in thedifferent ribs, then it turns rather sharply in a ventral change of direction produces the angle {angulus costce). Thedistance from tubercle to angle is greater in the eighth rib and nil inthe first rib. The rib is also twisted so that the ventral end is at alower level than the head, when the rib is placed upon a plane is most no
A manual of anatomy . 8 OSTEOLOGY the shortest. The curvature is not uniform but varies in the differentregions and gives the peculiar shape of the thorax. From the tuber-cle the rib proceed first laterally and at a variable distance in thedifferent ribs, then it turns rather sharply in a ventral change of direction produces the angle {angulus costce). Thedistance from tubercle to angle is greater in the eighth rib and nil inthe first rib. The rib is also twisted so that the ventral end is at alower level than the head, when the rib is placed upon a plane is most noticable in the seventh and eight ribs and least in thefirst and last ribs. The shaft is flattened and has two surfaces, lateral and lateral surface is smooth and convex and faces according to thepart of the thorax in which it is placed, , superiorly in the upper part,laterally in the middle of the thorax and slightly downward in thelower part. The medial surface is smooth and faces in the opposite Angle. Body Fig. i6.—The seventh rib of the left side seen from within. (Sobotta and McMurrich.) direction. The superior margin is thick and rounded and affordsattachments to the mm. intercostales externus et internus. Theinferior margin is sharp and dorsally it is grooved; here it forms thecostal groove {sulcus costalis) which disappears ventrally. The in-ferior margin, between the angle and the tubercle, is ridged andaffords attachment to the m. iliocostalis. The costal groove containsthe intercostal vessels and the lip affords attachment to the externaland internal intercostal muscles. In the groove are seen the nutrientforamina that are directed toward the vertebral extremity. Peculiar Ribs.—The first rib is the smallest. The head is smalland the head articulates with only one vertebral body, the first. Theneck is short and flattened from above downward. The tubercle,at the junction of the neck and shaft, is prominent and bears a smallfacet, on its under surface
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecthumananatomy, bookyea
