158 ANATOMY OF THE RABBIT 



The body of a vertebra is a cylindrical, or somewhat dorso- 

 ventrally flattened, mass of bone, which bears at either end an 

 articular surface for attachment to the body of the adjacent 

 vertebra. The articular surfaces are borne on thin plate-like 

 epiphyses, the epiphysial lines being evident even in older animals, 

 especially in the lumbar region. The arch of a vertebra is composed 

 of a lateral, vertical portion, the pedicle or root (radix arcus 

 vertebrae), at each side and a dorsal, transverse portion connecting 

 the tops of the pedicles, distinguished as the lamina. Each pedicle 

 is attached to one side of the dorsal surface of the body of the 

 vertebra so that the latter forms the floor of the vertebral foramen, 

 the pedicles constituting its sides and the lamina its roof. The 

 anterior and posterior margins of the pedicle are notched, each 

 notch or incisure being opposite that of the adjacent vertebra, so 

 that together they form a rounded aperture, the intervertebral 

 foramen (foramen intervertebrale), for the passage outward of a 

 spinal nerve. 



The arch of the vertebra bears various projections or processes. 

 On either side is a horizontal plate of bone, the transverse process 

 (processus transversus) and, dorsally, there is a median projection, 

 the spinous process (processus spinosus), all three serving for the 

 attachment of ligaments which hold the vertebrae together and 

 for the attachment of the spinal musculature. Special surfaces 

 for articulation with the adjacent vertebrae are borne on low 

 articular processes (processus -articulares) on the anterior and 

 posterior margins of the arch. The anterior or superior articular 

 surfaces are directed for the most part toward the dorsal surface, 

 and are overlapped in the natural condition by the inferior articular 

 surfaces of the next vertebra, which are directed more or less 

 ventrad. A certain amount of movement is permitted by one 

 surface slipping across the other, the mechanism illustrating the 

 arthrodia, or gliding-joint. 



Cervical Region 



The cervical vertebrae (vertebrae cervicales) are seven in 



number and serve mainly for the support of the head. As the 



latter has to be freely movable in a variety of directions, the 



articulations are such as to permit considerable flexibility in this 



