j ‘ LIGAMENTS OF THE VERTEBRAL COLUMN. 955 
“margin of the superimposed vertebra is overlapped on each side by the one which 
bears it, the disc does not extend to the extreme lateral margin, and in this position 
a small diarthrosis may be seen at each lateral margin of the disc. 
The anterior common ligament (lig. longitudinale anterius, Fig. 199) consists 
of a wide stratum of longitudinal fibres which extends from the front of the axis 
vertebra to the front of the upper segment of the sacrum, and becomes gradually 
wider from above downwards. It lies in front of the intervertebral discs, to which 
it is firmly attached as it passes from one vertebra to the other. Its fibres vary in 
length. Some are attached to contiguous margins of two adjoining vertebree ; 
others pass in front of one vertebra to be attached to the next below, and yet 
others find their lower attachment three or four vertebrae below the one from which 
they started. None of the fibres are attached to the transverse depression on the 
front of a vertebral body. 
The posterior common ligament (lig. longitudinale posterius, F ig. 200) is found 
within the spinal canal upon the posterior aspect of the vertebral bodies. It con- 
sists of longitudinal fibres, and it extends from 
the back of the sacrum to the axis vertebra, superior 
to which it is continued to the skull as the posterior 
occipito-axial ligament. Opposite each interverte- 
bral disc it is attached to the entire width of the 
adjacent margins of the two vertebral bodies, its 
fibres being continued over the posterior surface of 
the disc. In the lumbar and dorsal regions, the 
width of the lgament is considerably reduced 
opposite the back of each vertebral body, and thus 
if forms a series of dentate projections along both 
of its margins; but in the cervical region the 
width of the hgament is more uniform. 
One or two large thin-walled veins escape from 
the body of each vertebra under cover of this lga- 
ment. 
Interneural Articulations.—The neural arch 
of each typical vertebra carries two pairs of 
articular processes, by means of which it articu- 
lates with adjacent neural arches. The articu- 
lations between these processes are true diarthroses 
Pedicle of 
<a vertebra 
divided 
Posterior 
common 
ligament 
Interverte- 
bral fibro- 
cartilaginous 
disc 
of the arthrodial variety. Fic. 200.—PostTERIOR COMMON LIGAMENT 
pee f : OF THE VERTEBRAL COLUMN. 
The distinctive characters of these articular sur- 
faces, as regards their shape and direction in the different groups of vertebre, have 
been referred to in the section on osteology. 
All these articulations are provided with complete but very thin-walled cap- 
sules (capsule articulares), which are thinnest and loosest in the cervical region, 
where also the movements are freest. Each capsule is lined by a synovial 
membrane. 
Associated with these interneural joints are certain ligaments which are 
accessory to the articulations, although they are quite distinct from the capsule. 
The lamine of adjoining vertebree are bound together by the ligamenta subflava 
(ligamenta flava vel subflava, Fig. 201), which consist of yellow elastic fibres. The 
ligamenta subflava close the spinal canal in the intervals between the lamine. 
Each ligament is attached superiorly to the anterior aspect of one lamina at a 
short distance above its lower border, and inferiorly it is attached to the posterior 
aspect of the subjacent lamina. 
In the dorsal region, where the imbrication of adjoining laminz is a prominent 
feature, these ligaments are not so distinctly visible from behind as they are in the 
regions where imbrication of the laminz is not so marked. 
Laterally they extend as far as the articular capsules, while mesially the margins 
of the ligaments of opposite sides meet under cover of the root of the spinous process. 
Contiguous pairs of spinous processes are also attached to each other by inter- 
Spinous ligaments (ligamenta interspinalia, Fig. 198). These are strongest in the 
