OSTEOLOGY. 43 



we see the ribs running downwards from tlie lateral parts 

 of the body, continued by the sterno - costal cartilages, 

 between which, at their lower extremities, is the sternum or 

 hcemal spine. From various parts of the arches processes 

 project ; thus at the anterior and posterior extremity of 

 each lamina is an articular or oblique process, with a syno- 

 vial facet for union with the neighbouring vertebrae, A 

 process is also found on the point of union of the neural 

 laminae and pedicles which generally unites with another 

 from the point of junction of the pedicles and the centrum, 

 forming the transverse processes of the cervical and dorsal 

 vertebrce. The lumbar transverse processes consist simply 

 pf the inferior process, the superior in this region being 

 blended with the anterior oblique. The two in the cervical 

 region are distinct at their commencement, but united at 

 their free extremities ; thus they form, the vertebral fora- 

 mina. From the under surface of the centrum, in some 

 parts, a process arises and passes in a downward direction ; 

 this is generally termed the inferior spinous process. 



The spinal vertebrae, as a rule, present the centrum with 

 the neural arch and its processes. The centrum has a 

 flattened superior surface, from each extremity of which 

 triangular roughened surfaces extend towards the centre, 

 where their apices are slightly separated by a smooth 

 channel which connects other channels situated between 

 the roughened surfaces and the inferior extremities of the 

 laminae. The anterior surface of the body is convex, and 

 is attached by means of a disc of fibro-cartilage to the 

 posterior surface of the vertebra in front, which is corre- 

 spondingly concave. The extremities of the body are its 

 widest parts, so that its central portion is smallest ; it 

 presents two surfaces converging to form a prominent line 

 extending from before backwards along the under surface. 

 It is this line which, in some cases, forms the inferior 

 spinous process. The ring or arch of the vertebra is formed 

 by the lamince and pedicles ; the latter present grooves on 

 their anterior and posterior margins, and the anterior 

 groove of the vertebra, uniting with the posterior groove 

 of the vertebra in front of it, forms an intervertebral 

 foramen or gap, by means of which nerves escape from, 

 and vessels pass into, the spinal canal. The vertebrae of 

 the spinal column may be true or false, the true vertebrae, 

 or those which are capable of more or less extensive motion 



