A R TICULA Tl (>.\ N OF HI i: flP/JCE 131 



cervical vcrtebrrc, all tho dorsal and lumbar vcrtcbno, and the first sacral 

 vertebra. 



UNION OF THE VEUTEBHJE BY THEIR BODIES. Tho articulations forming this 

 uii ion are so many amphiarthroses. 



Articular surfaces. Tho vertebral bodies come into contact by tho 

 surfaces which terminate them before and behind. In tho cervical region 

 these surfaces represent, anteriorly, a veritable head, posteriorly, a cotyloid 

 cavity which receives the head of the next vertebra. Beginning from tho 

 first dorsal vertebra and passing on to the sacrum, these tend to become 

 effaced and more and more plane, though they still preserve their convexity 

 and concavity. 



Modes of union. I, By fibro-cartilages interposed between tho articular 

 surfaces ; 2, By a common superior vertebral ligament ; 3, By a common 

 inferior vertebral ligament. 



a. Inicrvcrtebral Jibro-cartilages (Fig. 80, 1, 1). These are circular or 

 elliptical discs, convex in front, concave behind, and solidly fixed by their 

 faces to the articular planes which they separate. The fibro-cartilaginous 

 substance composing them consists of concentric layers, which become denser 

 and closer to each other as they near the circumference ; they even disappear 

 towards the centre of the disc, where this substance becomes pulpy and 

 assumes the histological characters of 'pure cartilage. It may bo remarked, 

 that each of those layers is made up of a collection of thick parallel filaments, 

 which cross with those of other layers like an X, and are attached by their 

 extremities to the articular surfaces. From this arrangement results so inti- 

 mate an adherence between the vertebral bodies and their intermediate fibro- 

 cartilages, that an attempt to disunite them is more likely to determine a 

 fracture of the former. The fibro-cartilages, thicker in the cervical and 

 lumbar regions than in the dorsal, respond by their circumference to tho 

 two common ligaments. Those which separate the vertebra of the back 

 concur to form the intervertebral cavities, which are destined for the reception 

 of tho heads of the ribs, and give attachment to the interosseous costo- 

 vertebral ligaments. 



(Leyh designates the superficial fibres of the excentric layer of these 

 fibro-cartilages as intervertebral ligaments. Luschka has shown that tho 

 cartilages are in reality articular capsules.) 



b. Common superior vertebral ligament (Fig 83, 1). This ligament 

 extends from tho axis to the sacrum, and is lodged in the spinal canal ; it 

 r presents a long fibrous band cut on its borders into wide festoons. (The 

 wide portions correspond to the discs.) 



By its inferior face, it is attached to the intervertebral discs and Hie 

 triangular imprints on the upper faces of tho bodies of the vertebno. Its 

 superior face is in contact with the dura mater through the medium of an 

 abundant cellulo- adipose tissue. Its borders are margined by the intrn- 

 \vrtrbral venous sinuses (twice basium vertebrarium). 



c. Common inferior vertebral ligament (Fig. 84, 6). Situated under the spine 1 , 

 \\\-.< ligament is absent in the cervical and tho anterior third of thodoraal region . 

 It only really begins alxmt tho sixth or eighth vertebra of tho latter region, 

 ami is prolonged in the form of a cord, at first narrow, then gradually 

 widening until it reaches tho sacrum, on tho inferior surface of which it 

 terminal- s liy a decreasing expansion. I-'n-m it- c.-iiinirne. nieiit. it is 

 attach. -.1 t<> tin- interior crest of the bodies of the vertebra- ami tin- interval - 

 tel-ral di<.--;. !',y its inferior frier, it responds to tin- posterior aorta. 



ll Commences tliis ligament al tin- si v< ntli ecrvieal vert- lira, anil says 



