140 THE VERTEBRJE. 



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 vertebrae 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 vertebrae 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 vertebrae, 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 



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