268 ARTICULATIONS. 



2. LIGAMENTS CONNECTING THE LAMINA. 

 Ligamenta Subflava. 



The Ligamenta Subflava (Fig. 183) are interposed between the laminae of the 

 vertebrae, from the axis to the sacrum. They are most distinct when seen from 

 the interior of the spinal canal; when viewed from the outer surface, they 

 appear short, being overlapped by the laminae. Each ligament consists of two 

 lateral portions, which commence on each side at the root of either articular 

 process, and pass backwards to the point where the laminae converge to form 

 the spinous process, where their margins are thickest, and separated by a slight 

 interval, filled up with areolar tissue. These ligaments consist of yellow elastic 

 tissue, the fibres of which, almost perpendicular in direction, are attached to 

 the anterior surface of the margin of the lamina above, and to the posterior 

 surface, as well as to the margin of the lamina below. In the cervical region, 

 they are thin in texture, but very broad and long ; they become thicker in the 

 dorsal region: and in the lumbar acquire very considerable thickness. Their 

 highly elastic property serves to preserve the upright posture, and to assist in 

 resuming it, after the spine has been flexed. These ligaments do not exist 

 between the occiput and atlas, or between the atlas and axis. 



3. LIGAMENTS CONNECTING THE ARTICULAR PROCESSES. 

 Capsular. 



The Capsular Ligaments (Fig. 185) are thin and loose ligamentous sacs, 

 attached to the contiguous margins of the articulating processes of each verte- 

 bra, through the greater part of their circumference, and completed internally 

 by the ligamenta subflava. They are longer and more loose in the cervical 

 than in the dorsal or lumbar regions. The capsular ligaments are lined on 

 their .inner surface by synovial membrane. 



4. LIGAMENTS CONNECTING THE SPINOUS PROCESSES. 

 Inter-spinoug. Supra-spinous. 



The Inter-spinous Ligaments (Fig. 183), thin and membranous, are interposed 

 between the spinous processes in the dorsal and lumbar regions. Each ligament 

 extends from the root to near the summit of each spinous process, and connects 

 together their adjacent margins. They are narrow and elongated in the dorsal 

 region, broader, quadrilateral in form, and thicker in the lumbar region. 



The Supra-spinous Ligament is a strong fibrous cord, which connects together 

 the apices of the spinous processes from the seventh cervical to the spine of the 

 sacrum. It is thicker and broader in the lumbar than in the dorsal region, and 

 intimately blended, in both situations, with the neighboring aponeuroses. The 

 most superficial fibres of this ligament connect three or four vertebras ; those 

 deeper seated pass between two or three vertebrae ; whilst the deepest connect 

 the contiguous extremities of neighboring vertebrae. 



5. LIGAMENTS CONNECTING THE TRANSVERSE PROCESSES. 

 <\ 



Inter-transverse. 



The Inter-transverse Ligaments consist of a few thin scattered fibres, interposed 

 between the transverse processes. They are generally wanting in the cervical 

 region; in the dorsal, they are rounded cords; in the lumbar region they are 

 thin and membranous. 



Actions. The movements permitted in the spinal column are, Flexion, Ex- 

 tension, Lateral Movement, Circumduction, and Rotation. 



In Flexion, or movement of the spine forwards, the anterior common liga- 

 ment is relaxed, and the intervertebral substances are compressed in front; 



