NUMERICAL VARIATION IN THE HUMAN SPINE. 



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sacrum of childhood. The lateral masses of the 25th are very sacral in character, touching 

 those of the vertebra below, though of course not fused at tliis early age. They form a 

 portion of the auricular surface, though less than half as much as those of the 26th, which 

 is certainly ihefulcralis. It is probable that the auricular surface extends to the 2d sacral. 

 The disc below the 25th in the dried spine is almost as thick as the one above it. 



561. Cat. 9379-15. 



Male, white, aet. 28. C. 7, T. 13, L. 5, S. 5, C. imperfect. 



This spine shows a tendency to shorten at the upper end, by the atlas fusing with the 

 occiput, and to lengthen Ijelow, the 25th vertebra not being a true sacral. There is also 

 some confusion at the junction of the back and loins. The fusion of the atlas with the 

 occiput is pretty nearly complete, Ijut the parts of the former are all distinct. On the right 

 the arch tends to lose its incUviduality, while on the left there is a space between it and 

 the skull. The neck and back present nothing peculiar above the 12th riljs, which are very 

 long: 15.3 cm. (m the right. 15. em. on the 

 left, following the conca\aty. The heads 

 are placed higher than normal, encroaching 

 largely on the cartilage above the \-ertebra. 

 The 13th pair of costal elements, though 

 movable, resemble very closely lumbar 

 transverse processes, especially the left 

 one, the right being more slender and rib- 

 like. Each measures 2.5 cm. The change 

 of the articular processes is 1)elow the 2()th 

 vertebra. The first lumbar transver.se proc- 

 esses are .small, after which their spread 

 is about the same. The 5th luml)ar is 

 transitional and unsymmetrical. The body 

 is deeper on the left, and the lateral mass 

 of that side the larger, with a rudiment of 

 a transverse process. It is boimd close to 

 the ilium and probably forms a small part 

 of the johit. On tlie right it does not 

 quite touch the iUum. The 3d piece of the 

 sacrum has no sliare in the auricular sur- s^i. 



face of the left, and but a very slight one on the right. It is the seat of the ronjvr/afa 



