AR TICULA TIONS. LIGAMENTS. 46 1 



and false vertebrae. The false vertebrae, nine in number, five sacral and four 

 coccygeal, make by their fusion the sacrum and coccyx. 



Name tlie regions of tlie vertebral column and give sonic reasons for a regional 

 subdivision of tJic column. 



The vertebral regions and the number of bones in each are : (i) Cervical 

 reg'on, containing seven bones ; (2) dorsal or thoracic region, containing twelve 

 boius ; (3) lumbar region, containing five bones ; (4) sacro-coccygeal region, con- 

 taining nine bones. Subdivision of the vertebral column into regions depends on 

 a difference in form of the bones, while this difference in the form depends on the 

 function of the region in which the bones are located ; growth predetermines 

 form, and is the correlative of function. 



What is tlie natural arrangement of adjacent vertebne to cadi other / 



They are in juxtaposition that is, one next to another, with parallelism of 



Portion of ligamen- 

 tum subflavum re- 

 moved to show the 

 articular cavity 



Iiigamentum 

 subflavum 



1/11 ; - 333- LlGAMENTA SUBFLAVA IN THE LUMBAR REGION. 



homologous parts. Thus, this arrangement among the bones of the vertebral 

 column gives a logical basis for studying the ligaments of the column, since we 

 find : Juxtaposition of bodies ; juxtaposition of pedicles ; juxtaposition of lam- 

 inae ; juxtaposition of articular processes ; juxtaposition of spinous processes ; 

 juxtaposition of transverse processes. 



Wliat is t/ie function of the bodies or centra, and by u'hat ligaments are they 

 held together .' 



They give solidity and strength to the column. The ligaments of the bodies 

 or centra are the anterior common, posterior common, and intercentral discs of 

 fibro-cartilage. Their union forms an amphiarthrodial articulation, since bone is 

 united to bone by cartilage with limited motion. 



Give the function and relations of tlie pedicles. 



The pedicles support the neural arch. Above and below them are found 

 the intervertebral notches, which are converted into intervertebral foramina when 



