190 THE ARricriATioys 



THE ARTICULATIONS OF THE TRUNK 



These may be divided into the following sets: — 



1. Those of the vertebral colunm. 



(a) Union of the bodies. (h) Union of the articular processes. 



2. Vertebral cohnnn -with the pelvis. 



3. Pelvis. 



(a) Sacro-iliac synchondroses. (f) Intercoccygeal. 

 (6) Sacro-coccygeal. {d) Symphysis pubis. 



4. Ribs with the vertebral column. 



5. The articulations at the front of the thorax. 



(a) Costal cartilages with the sternum. 

 (6) Costal cartilages with the ribs. 



(c) Sternal. 



(d) Certain costal cartilages with each other. 



1. THE ARTICULATIONS OF THE VERTEBRAL COLUMN 



There are two distinct sets of articulations in the vertebral column: — 



(a) Those between the bodies and intervertebral discs which form amphi- 



arthrodial joints. 

 (&) Those between the articular processes Avhich form arthrodial joints. 



The ligaments which unite the various parts may also be divided into two sets, 

 viz. — immediate, or those that bind together parts which are in contact; and 

 intermediate, or those that l)ind together parts which are not in contact. 



Immediate. 



(a) Those between the bodies and discs. 

 (6) Those between the articular processes. 



Intermediate. 



(c) Those between the lamina?. 



(d) Those between the spinous processes. 



(e) Those between tlie transverse processes. 



(r() TiiK Articulations of the Bodies of the Vertebrae 



Class. — AiiipJiidiiJirosis. 



The ligaments Avhich unite the bodies of the vertebra? are: — 



Intervertebral discs. Anterior connnon. 



Short lateral ligaments. Posterior common. 



The intervertebral substances (figs. 195 and 199) are tough, but elastic and 

 compressible discs of cumjjositc structure, which serve as the chief bond of union 

 between the vertebra?. They are twenty-three in number, and are interjiosed 

 between the bodies of all the vertebne from the axis to the sacrum (figs. 195 and 

 20()). Similar sulxstances are found between the segments of the sacrum and 

 coccyx, but they undergo ossification at their surfaces and often throughout their 

 whole extent. 



