50 



LIGAMENTS OF THE VERTEBR-E. 



for the protection of vessels or nerves from the contraction of the 

 pterygoid muscles, between which it passes from the spinous process 

 of the sphenoid to the spine at the margin of the posterior mental 

 foramen.'* (Fig. 31.) 



Stylo Maxillary,^ (Fig. 31), is an extremely thin fibrous band ex- 

 tending from the styloid process of the temporal bone to the angle of 

 the lower jaw. 



Fig. 31. Fig. 32. 



Internal Articular Cartilage^ is a thin oval plate, dividing the 

 joint into two cavities. It is partly concave above and below, thick 

 at the edges. (Fig. 32.) 



The Two Synovial Membra?ies* ^ (Fig. 32.) One is reflected 

 between the glenoid cavity and the interarticular cartilage ; the other 

 between the cartilage and the condyle of the jaw. When the cartilage 

 is perforate, the two cavities are lined by one synovial membrane. 



LIGAMENTS OF THE VERTEBRAE. 



BODIES. 



Intervertebral Substance. — The bodies of the vertebrse are united 

 by fibro-cartilaginous disks, which are twenty -three in number, con- 

 sisting of concentric rings ; toward the centre there is a yellow jelly- 

 like mass, in a state of compression ; it is whiter and more abun- 

 dant in infancy. On this account persons are stiffer in old age, and 

 are shorter in the evening than they are in the morning. 



Anterior Vertebral Ligament^ is in front of the bodies of the ver- 

 tebrae (Fig. 35*) ; extending from the second vertebrre of the 

 neck to the first of the sacrum ; it is thin and gradually increases in 

 breadth. 



Posterior Vertebral Ligament. — It lies upon the posterior sur- 

 face of the bodies of the vertebrae, and extends from the occiput 

 to the os-coccygis ; it is narrow and thick in the thorax, adheres 

 closely to the intervertebral substance, and its edges present a ser- 

 rated appearance. 



Processes. — Oblique. — These are surrounded by capsular liga- 

 ment, lined by a synovial membrane. 



