357 



Nachdruck verboten. 



1 further Note on tlie Case of Fusion of the Atlas and Axis. 



By G. Elliot Smith. 



Two years ago I described a case of fusion of the atlas and axis 

 vertebrae^) with partial assimilation of tbe right atlantal arch to the 

 axis. I gave reasons for the belief that this condition was not due 

 to any pathological process, but was the result of some developmental 

 eccentricity. 



At the time my first note on this specimen was written I did not 

 attach sufficient importance to the condition of the rest of the verte- 

 bral column to deem it worthy of record. But since then the study 

 of Professor Dwight's instructive series of memoirs on spinal variations 

 and my own investigations on the association of occipital anomalies 

 with far reaching modifications of the vertebral column have convinced 

 me that I have omitted to put on record the most instructive features 

 •of the spine in question. 



The skull in this case showed an excellent "manifestation of an 

 occipital vertebra" (Kollmann). On the right side (the left was broken) 

 of the seventh cervical vertebra there was a well-developed rib, although 

 it was not free but was firmly ankylosed to the vertebra. The twelfth 

 ribs were exceedingly diminutive, and it was impossible to recognise 

 ^ny costal facet on the left side of the twelfth dorsal vertebra. The 

 fourth lumbar vertebra had assumed the characters, which are usually 

 distinctive of the fifth, and the real fifth had fused to the sacrum. 



Thus the cranio- vertebral column of this man exhibited signs of 

 disturbance at every transition-region. The interest in this case centres 

 chiefly in the fact that a spinal column of the normal number of ele- 

 ments exhibits a whole series of harmonious variations, and not the 

 disharmonious but compensatory anomalies, which commonly occur in 

 abnormal spinal columns. The usual type of variation has been thus 

 described by Dwight '') : "Variation of the costal elements at one end 



1) Anat. Anz., Bd. 31, No. 6, 1907^ p. 166. 



2) Anat. Anz., Bd. 28, No. 1 und 2, 1906, p. 33. 



