132 THE ARTICULATIONS. 



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 t 

 the pillars of the diaphragm and confounded on each side with the large 

 ligaments of the pelvis.) 



UNION OP 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. 



Modes of union. 1, A common superspinous ligament ; 2, Interspinous 

 ligaments ; 3, Interlamellar ligaments ; 4, Ligamentous capsules, proper 

 to the articular processes. 



a. Common, superspinous ligament. This ligament, whose name suf- 

 ficiently indicates its situation, extends from the sacrum to the occipital bone 

 and is divided into two portions : one posterior, or superspinous dorso-lumbar 

 ligament; the other anterior, or superspinous 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. Super dor so-lumbar ligament (Fig. 80, 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 aponeuroses of the common mass of muscles. 



2. Superspinous cervical, or simply cervical ligament (Fig. 104, 1, 2). 

 This ligament is entirely formed of yellow fibrous tissue, and constitutes, 

 in the median plane of the body, a very remarkable elastic apparatus which 

 separates the superior cervical muscles of the right side from those of the 

 left, and plays the part not entirely of an articular band, but rather of a 

 permanent stay charged to balance the weight of the head. 



In the cervical ligament there is distinguished & funicular and a lamellar 

 portion. The first, usually called the cord of the cervical ligament, is a 

 wide funiculus which extends directly from the first dorsal spinous processes 

 to the summit of the head. Divided into two lateral lips by a median groove, 

 this cord is continued posteriorly with the dorso-lumbar ligament, and is 

 inserted forwards into the cervical tuberosity of the occipital bone. It is 

 covered above by a mass of fibro -adipose tissue which, in certain common- 

 bred horses, is very abundant. Below, it gives rise, in its posterior two- 

 thirds, to the majority of the fibres belonging to the lamellar portion. On 

 the sides, it receives the insertions of several cervical muscles. The lamellar 

 portion, comprised between the funicular portion, the spinous processes of the 

 second dorsal vertebra, and the cervical stalk, constitutes a vast triangular 

 and vertical septum, which itself results from the apposition of the two 

 laminae which lie back to back, and are united by cellular tissue ; they are 

 bordered above by the two lateral lips of the cord. The elastic fibres which 

 enter into their composition are given off either from the latter, or from the 

 spinous processes of the second and third dorsal vertebrae ; they are directed 

 downwards or forwards, and reach the spinous processes of the last six 

 cervical vertebrae, into which they are inserted by so many digitations, 



