NUMERICAL VARIATION IN THE HUMAN SPINE. 



285 



85. Cat. 9379-43. 



Female, white. C. 7, T. 12, L. 4, S. and C. 10. 



A delicate spine. Nothing to note in neck nor in back till the 12th thoracic is 

 reached. The 12th left rib, abont 4.5 cm. long, is clearly a ril) with a head and a sub- 

 costal groove. The right one is lost, but there is a facet for the head on the root of the 

 pedicle in a corresponding place to that for the left one. The change of the articular 

 surfaces occurs above this vertebra (19th), but is rather transitional on the right. The 

 spinous process is thoracic rather than lumbar. In the lumbar region the spread of the 

 transverse processes is greatest at the 3d. The 4th has rather the appearance of the penul- 

 timate. The 24th vertebra is the 1st sacral. The promontory is above it, and there is 

 the merest hint of a false one below it. On the right the transverse process is more out- 

 lined than on the left. On the left this vertebra is the fidcralis beyond any possibility of 

 doubt; on the right it is less certain. The arch is fused with the rest of the sacrum. 

 There is a faint line of change of direction across the body of the 3d sacral, at about the 

 level of the lower borders of the auricular surfaces. The sacrum is of sLx pieces, but the 

 last beyond question is the 1st coccygeal. It is thoroughly fused so as to inclose a fifth 

 sacral foramen. There are four coccygeals below this, but the highest of them is too 

 small to pass for a normal 1st one. 



The following measurements were made on the fresh spine. 



Average length, female. Proportions of 85. Average proportions. 



12.1 cm. 

 26.5 



18.7 

 5L3 



22.5 % 



48.5 



29.0 



100.0 



21.2 % 



46.1 



32.7 



100.0 



Two things are apparent : first that the spine is a short one, second that another ver- 

 tebra in the loins would go far to re-establish the proportions. Hence it is evident that 

 the compensation in this case is slight. 



377. Cat. 9379-25. 



Female, white. C. 7, T. 12, L. 4, S. 5, C. 4. 



A praesacral vertebra is wanting ; but there is some doubt whether it is lost from the 

 thorax or loins. There are 11 pairs of ribs, and the 19th vertebra has neither ribs nor 

 transverse processes. The bod^ has no certain facet for the head of a rib, but there is the 



