VERTEBRAL LIGAMENTS 



229 



esses and the posterior roots of the transverse processes of two contiguous vertebrae. In the 

 thoracic region the tibres are shorter, and vertical in direction, and are attached to the bases 

 of the transverse' processes; in the lumbar, they are obhquely transverse. The articular 

 capsules in the cervical region are the most lax, those in the lumbar region are rather tighter, 

 and those in the thoracic region are the tightest. 



There is one synovial membrane to each capsule. 



(c) The Ligaments uniting the Lamina 



The ligamenta flava (fig. 268) are thick plates of closely woven yellow elastic 

 tissue, interposed between the laminse of two adjacent vertebrse. The first con- 

 nects the epistropheus with the third cervical, and the last the fifth lumbar with 



Fig. 268. — Ligamenta Flava in the Lumbar Region, seen from within the Vertebral 

 Canal. 



Portion of ligamentum 

 flavum removed to 

 show the articular 

 cavity 



Ligamentum flavum 



the sacrum. Each ligament extends from the medial and posterior edge of the 

 intervertebral foramen on one side to a corresponding point on the other; above, 

 it is attached close to the inner margin of the inferior articular process and to a 

 well-marked ridge on the inner surface of the laminse as far as the root of the 

 spine; below, it is fixed close to the inner margin of the superior articular process 

 and to the dorsal aspect of the upper edge of the laminse. 



Thus each ligamentum fiavum, besides filling up the interlaminar space, enters into the 

 formation of two articular capsules; they do so to a greater extent in the thoracic and lumbar 

 regions than in the cervical, where the articular processes are placed wider apart. When seen 

 from the front after removing the bodies of the vertebra;, they are concave from side to side, 

 but convex from above downward; they make a more decided transverse curve than the arches 

 between which they are placed. This concavity is more marked in the thoracic, and still more 

 in the lumbar region than in the cervical; in the lumbar region the Ugamenta flava extend a 

 short distance between the roots of the spinous process, blending with the interspinous ligament, 

 and making a median sulcus when seen from the front ; there is, however, no separation between 

 the two parts. In the cervical region, where the spines are bifid, there is a median fissure in the 

 yellow tissue which is filled up by fibro-areolar tissue. The ligaments are thickest and strongest 

 in the lumbar region; narrow but strong in the thoracic; thinner, broader, and more membranous 

 in the cervical region. 



(d) The Ligaments connecting the Spinous Processes 



These include supraspinous ligament, interspinous ligaments, and the liga- 

 mentum nuchse. 



