416 



transverse processes of the sacral vertebrae develope epiphyses, nor do 

 I find any mention of epiphyses in connection with either costal pro- 

 cesses or maramillary processes. 



Before the manner of ossification of the auricular facets, costal 

 processes and transverse processes can be understood it is necessary 

 to examine and study the ossification of the 5th lumbar vertebra, be- 

 cause it seems to give the key to the ossification of the sacrum. 

 And before even studying the ossification of this vertebra it may be 

 well to examine its appearances in the adult, both in what may be 

 called its normal condition, and in that condition in which it is evi- 

 dently taking on sacral characters — or in other words — where it 

 is fusing with the sacrum on one side. 



If one then examines a 5th lumbar vertebra from the front, as 

 represented in Fig. 1 one can see passing outwards from the centrum 

 and pedicle on each side a process, called by some transverse, by 

 others costal. This process can be seen to present to view two seg- 

 ments, one, more anterior which springing apparently from the centrum 



turns downwards and outwards 

 rapidly diminishing in size in 

 its outward course until it ends 

 in a slight projection at the 

 under margin of the whole 

 outwardly projected process 

 (Fig. 1 C); the other, con- 

 tinuous with the previous seg- 

 ment springing more particu- 

 larly from the pedicle and 

 lateral mass has a direction upwards and backwards ending in a 

 blunted extremity (Fig. 1 T). 



If now a 5th lumbar vertebra be examined which is in process 

 of fusion with the sacrum, as shown in Fig. 2, enormous increase in 

 size of that segment of the outgrowing process from the centrum, 

 above described, is noticed and moreover it becomes separated by a 

 wide gap at its outer end from the more posterior part of the out- 

 growing process (Fig. 2). Still more are these appearances accentuated 

 in the first sacral vertebra. 



The whole is exceeding suggestive as to the outgrowing process 

 of the 5th lumbar vertebra being both costal and transverse, — if the 

 commonly accepted view, as to the corresponding elements in the 

 sacrum being costal and transverse, be correct. 



The ossification of this process in the 5th lumbar vertebra seems 



Fig. 1. The 5th Lumbar vertebra from 

 the front. C. Costal process. T. Transverse 

 process. 



