514 L. BOLK 



ON THE OBLITERATION OF ONE OF THE OTHER SUTURES OF THE 



SKULL 



In considering the occurrence of premature obliteration a 

 striking difference is observed between the sagittal and masto- 

 occipital suture on the one hand and all the other sutures on 

 the other. A special discussion therefore upon the sutures just 

 mentioned seems desirable in every respect. The frequency of 

 premature closure in the other sutures being very small, there 

 is no ground to describe each of these in a special paragraph. 

 I will subsequently communicate the results of my investigation 

 on each of these sutures. I wish to point out that for the present 

 only those cases are being discussed in which the obliteration is 

 limited to one single suture. 



I shall begin with the coronal suture. There is a notable 

 difference between the coronal and sagittal suture concerning 

 the starting point from which the obUteration begins. This 

 point is always the same in the sagittal suture, it is the so- 

 called obelion. I have found no cases in which the frontal half 

 of this suture was closed, while the occipital was left open. In 

 the coronal suture on the contrary this regularity does not 

 exist at all and the synostosis between the parietal and frontal 

 bones may commence at any point of the suture. Moreover the 

 synostosis in most cases is asymmetrical and only proceeds more 

 symmetrically when starting at the bregma-point. These differ- 

 ences clearly show that the process in the coronal suture in some 

 ways is of another character compared with the sagittal suture. 



In table 4 I gathered the cases in which the coronal suture 

 was partially or totally obliterated. 



A comparison of the contents of this table and the former, 

 referring to the ' sagittal and masto-occipital suture, shows 

 immediately that here one has to reckon with a different cate- 

 gory of phenomena. For a non-complicated obliteration of 

 the coronal suture only appeared in 6 of the 1820 infantile 

 skulls. Therefore one can surely consider a premature ob- 

 literation of this suture to be exceptional. Once more I lay 

 stress upon this fact, because it is of great importance for the 

 general question concerning the etiological nature of the pre- 



