26 ANTHROPOLOGY. 
The posterior vertebral ligament ( pl. 124, fig. 7*), in part a prolongation of 
the apparatus ligamentosus, extends down the back part of the bodies of 
the vertebre, along the front of the spinal canal. It adheres more closely 
to the edges of the vertebre and to the intervertebral ligaments than to the 
middle of each vertebra, and runs out in the sacral canal. Its object is to 
give strength to the spine by opposing too much flexion of the column. 
The intervertebral ligaments ( fig. 10**) are placed between the bodies of 
all the vertebra except of the first and second. They are fibro-cartilages, 
partaking both of cartilage and ligament in their character. Their union 
above and below to the flat surfaces of the vertebre is so intimate, that 
maceration or boiling alone can separate them completely ; and their own 
strength and cohesion surpass that of even the bones themselves, the bone 
breaking before the ligament can be ruptured or torn from its attachment. 
In the neck and loins they are thicker in front than behind, the contrary 
being the case in the back; this causes much of the peculiar curvature of | 
the spine. 
The oblique or articulating processes of the vertebree are connected by 
synovial membranes and by ligamentous capsules extending irregularly 
around these so as to form imperfect capsular ligaments. 
The ligamenta subflava (fig. 11") are situated between the back parts of 
the plates or the arches of the vertebrze; they close the intervals between 
them, and thus complete the back ,part of the spinal canal. The name is 
derived from their yellow color.« The supra-spinous lyament (fig. 12°) 
extends in the median line from the occiput to the sacrum, connecting the 
extremities of the spinous processes. The cervical portion is usually 
considered as a distinct portion under the name of ligamentum nuche, 
attached above to the occipital bone, below to the last cervical spine, and 
intermediately by distinct slips to all the cervical spines except that of the 
atlas. The interspinous ligaments (fig. 12°) are fibrous membranes placed 
vertically, and filling the space between the spinous process. ‘The «ter- 
transverse ligaments are ligamentous fibres extending between the transverse 
processes. 
4, SPECIAL ANATOMY OF THE T'HORAX. 
A. Bones of the Thorax. 
The thorax is constituted posteriorly by the twelve dorsal vertebree, 
laterally by the twelve pairs of ribs, and anteriorly by the costal cartilages 
and sternum. 
The sternum or breast bone ( pl. 122, fig. 3, H) is situated in the anterior 
portion of the thorax, in its median line. The anterior surface is flat or 
slightly convex, and is marked by transverse lines which indicate an 
original division into six pieces. Of these lines the two uppermost are 
most prominent. The posterior surface is smooth and slightly concave. 
The superior or cervical end is thick and broad, and very concave trans- 
versely. In the adult, it consists of three distinct divisions, the upper of 
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