180 THE ARTICULATIONS. 



mater, through the medium of an abundant cellulo-adipoae tissue. Its borders 

 are margined by the intra-vertebral venous sinuses (vrnm basium vertehrarium). 



c. Common inferior vertebral ligament (Fig. 127, 5). — Situated under the 

 spine, this hgament is absent in the cervical, and the anterior third of the dorsal 

 region. It only really begins about the sixth or eighth vertebra of the latter 

 region, and is prolonged in the form of a cord — at first narrow, then gradually 

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

 terminates by a decreasing expansion. From its commencement, it is attached to 

 the inferior crests of the bodies of the vertebras and the intervertebral discs. By 

 its inferior face, it is in contact with the posterior aorta. 



(Leyh commences this ligament at the seventh cervical vertebra, and says 

 that it adheres to the crests on the bodies of the dorsal and lumbar vertebrae, as 

 well as to the lower face of the sacrum and coccyx. At the fifth dorsal vertebra 

 it widens and thickens, and in the lumbar region is bound up with the pillars 

 of the diaphragm, and confounded on each side with the large ligaments of the 

 pelvis.) 



Union of the Vertebra by their Spinal Portions. — Each vertebra, in 

 uniting by its annular portion with that which follows or precedes it, forms a 

 double arthrodial joint. 



Articular surfaces. — These are the facets cut on the anterior or posterior 

 articular processes, and which have been described when speaking of the vertebrae 

 themselves. They are covered by a thin layer of cartilage. 



3Ieans of union. — 1. A common supra-spinous ligament. 2. Interspinous 

 ligaments. 3. Interlamellar ligaments. 4. Ligamentous capsules, proper to the 

 articular processes. 



a. Capsules proper to the articular processes (Fig. 124, 5). — Each anterior 

 articular process is maintained against the corresponding posterior process, by a 

 direct band. This is a peripheric capsule attached around the diarthrodial facets, 

 lined by a synovial membrane which facilitates their gliding, and covered, 

 outwardly, by the insertions of some spinal muscles. These capsules, yellow and 

 elastic in the cervical region, are composed of white fibrous tissue in the dorso- 

 lumbar region. Very developed at the neck, in consequence of the thickness of 

 the articular tubercles they envelop, they become reduced, near the middle of 

 the back, to some fibres which cover, outwardly, the diarthrodial facets in 

 contact. 



b. Common supraspinous ligament. — This ligament, the name of which suffi- 

 ciently indicates its situation, extends from the sacrum to the occipital bone, and is 

 divided into two portions — one posterior, or supraspinous dorso-lumbar ligament ; 

 the other anterior, or supraspinous cervical ligament. These two ligaments, 

 although continuous with one another, yet differ so strikingly in form and 

 structure that they are best described separately. 



1. Supra-dorso-lumbar ligament (Fig. 127, 2). — This is a cord of white 

 fibrous tissue, which commences behind on the sacral spine, and ceases in front, 

 about the inferior third of the dorsal region, by insensibly assuming the texture 

 and elasticity of the cervical ligament, with which it is continuous. It is attached 

 in its course to the summits of all the lumbar spinous processes, and to the ten or 

 twelve last dorsal. On the sacral spine, it is confounded with the superior 

 ilio-sacral ligaments. In the lumbar region, it is united on each side to the 

 ajjoneuroses of the longissimus dorsi muscles. 



2. Supraspinous cervical, or simply cervical ligament {ligamentum nuchm, liga- 



