120 ANATOMY OF THE RABBIT. 
enclose a large aperture, the vertebral foramen (foramen verte- 
brale). The successive foramina form an almost complete tube, 
the vertebral canal (canalis vertebralis), for the accommodation 
of the spinal cord. 
The body of a vertebra is a cylindrical, or somewhat dorso- 
ventrally compressed, mass of bone, which bears at either end an 
articular surface for attachment to the adjacent vertebra. The 
articular surfaces are borne on thin plate-like epiphyses, the epiphy- 
sial lines being evident even in older animals, especially in the 
lumbar region. The dorsal portion of the body bears on either side 
the pedicle, or root of the vertebral arch (radix arcus vertebrae), 
the dorsal surface of the body forming in this way the floor of the 
vertebral foramen. The dorsal portion of the arch, borne on the 
pedicle, is distinguished as the lamina. The anterior and posterior 
margins of the pedicle are notched, each notch or incisure being 
converted, through its association with that of the adjacent verte- 
bra, into a rounded aperture, the intervertebral foramen (fora- 
men intervertebrale), for the passage outward of a spinal nerve. 
The arch of the vertebra is noteworthy for its projections or 
processes. On either side is a horizontal plate of bone, the 
transverse process (processus transversus), and, dorsally, a 
median projection, the spinous process (processus spinosus), all 
three serving for the attachment of the vertebrae to one another 
by ligaments, and for the attachment of the spinal musculature. 
Special articular surfaces, borne on low articular processes 
(processus articulares), are found 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, which are directed toward the ventral surface. A 
certain amount of movement is permitted by one surface slipping 
across the other, the mechanism illustrating the arthrodia, or 
gliding-joint. 
The cervical vertebrae (vertebrae cervicales) are seven in 
number. The posterior five are similar, while the anterior two are 
specially modified in relation to the skull. The posterior vertebrae 
(Fig. 56, C) are dorsoventrally compressed, their arches low, and 
the spinous process short. In the seventh vertebra, however, the 
spinous process begins to be elongated as in the succeeding thoracic 
a a re 
