140 THE VERTEBRA. 



and articulated with the -two upper processes of the vertebrae 

 below, having their articular ligaments fixed into the rough line 

 round their edges. These processes are termed the oblique 

 or articulating. *" 



From between the oblique processes of each side, another pro- 

 cess extends laterally, which is called the transverse. 



From the back part of the roots of the two oblique processes, 

 and of the transverse process of* each side, a broad oblique bony 

 plate called the lamella is extended backwards : where these 

 meet, the seventh process of the vertebra takes its rise, and 

 stands out backwards. This being generally sharp-pointed and 

 narrow-edged, it has therefore been called spinous process ; 

 from which this whole chain of bones has got its name. 



Besides the common ligament which lines all the internal sur- 

 face of the spinous processes as well as of the bodies, particular 

 ligaments connect the bony bridges and processes of the contig- 

 uous vertebrae together. 



The substance of the processes is considerably stronger and 

 firmer, and has a thicker external plate than the bodies of the 

 vertebrae themselves. 



The seven processes form a concavity at their forepart, which, 

 joined to the one at the back part of the bodies, make a great 

 hole ; and when the vertebra are placed upon each other in 

 their natural order, these holes form a long tube for containing 

 the spinal marrow. 



In the upper and lower edge of each lateral bridge or pedicle, 

 there is a notch. These are so adapted to each other in the 

 contiguous vertebras, as to form a round hole in each side, be- 

 tween each two vertebrae, through which the nerves proceed 

 from the spinal marrow, and its blood-vessels pass. 



The articulations of each two vertebrae are consequently 

 double ; for their bodies are joined by the intervening cartilage 

 above described ; and their oblique processes, being tipped 

 with cartilages, are connected together by ligaments so as to al- 

 low a small degree of motion on every side. Hence, it is evident 

 that their centre of motion is altered in different positions of 





