NUMERICAL VARIATION IN THE HUMAN SPINE. 



263 



regular peuultimate. The lateral masses of the sacrum extend 

 upwai'd towards the transverse processes of the last lumbar, so that 

 this like the last represents a low degree of the freedom of the 25th 

 vertebra. The sacrum and coccyx are all in one piece. Verv little 

 if any of the od sacral forms a part of the auricular surface. The 

 change oi (Urection of the surface occui-s in the od. 



Here is an evident addition to the thorax with irregularities at 

 both ends of that region. This can hardly be accounted for simply 

 by the failure of the sacrum to advance. It is important to notice 

 that instead of there beiilg a concomitant enlargement of the left 

 13th ril) with the undeveloped concUtion of the 1st left one, the 

 former is smaller than its fellow. 



"^5 



704. Cat. l.)37U-8. 



Male, white, aet. 84. (The identity of this spine is not aljso- 

 lutely certain ; that is to say it may not have l)elouged to a white 

 man of 84, but it is a ligamentous preparation like the rest.) A part 

 of the atlas has been cut away. C. 7, T. 13, L. o, S. 5, (C. o ? ) . 



The 13th ribs are each about -3 cm. long. The change in the 

 articular processes is below the vertebra bearing tliem (2(lth). which 

 has a spine appi'oachiug the lumbar type. The spread of the lumbar 

 transverse processes increases to the 3(1. Tbe 24th and 20th aie 

 penultimate and ultimate lumljars. The five sacral vei'tebi-ae are 

 very normal, except that tlie 1st has the lateral masses rising higher 

 than usual. The change in the curve seems to occui- in the 3(1 

 sacral. The auricular surface is on three vertebrae. Tlie 1st piece 

 of the cocc_yx is, perhaps, fused with the sacrum, luit apparently this 

 was a change due to old age. It is not fused with the others, which 

 are united into one bone, probably consisting of four pieces ; but this 

 is not certain. The costal elements of the atlas are small, and on 

 the left imperfect. 



This spine is interesting as, while ha\-ing essentially the same 

 vertebral formula as the last, it is in many respects a more finished 

 spine. In the last the sacrum tended to invade the loins, and both 

 ends of the thorax were irregular. In this the sacrum, though 

 tenchng to rise on the sides, does so nuuli less, and the two ends 



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764, 



