167 



not involved such separation from the axis. The arcus anterior of 

 the atlas is fused to the front of the odontoid process (dens epistrophei) 

 and the capsular ligaments surrounding the obliterated joints between 

 the articular surfaces of the originally separate bones are ossified ; as 

 also is the anterior atlanto-axoid ligament, except at one spot on the 



Pars sinistra ^ 

 arc. post. /■ — •» .^ 

 atlantis J '^^- 



Fig. 2. The posterior aspect of the same. 



Pars dextra arc. 

 post, atlantis 



left side (Fig. la), where a foramen exists between the anterior arch 

 of the atlas and the axis, immediately to the inner side of the fused 

 articular processes. 



The right side of the ligamentum transversum atlantis (Fig. 3 *) 

 has become ossified and ankylosed to the odontoid process. 



/ 



Pars sinistra arc 

 post. atl. (free) 



\ 



Pars dextra arc. 

 post. atl. (fixed) 



Fig. 3. The upper aspect of the same. The asterisk (*) points to the ossified 

 right half of the ligamentum transversum atlantis. The transverse processes had been 

 damaged before the specimen came into my possession : they are represented by dotted 

 lines. 



The process of fusion must have occurred long before the two 

 halves of the posterior arch become joined, for the two parts have 

 remained widely separated. Whereas the left half (Figures 2 and 3, 

 pars sinistra arc. post, atlantis) has maintained its normal position, 



