FONTANELLA METOPICA IN AN ADULT SKULL 



263 



of a fine bristle. The transverse portion presents itself on the 

 inner surface as eight short perpendicular adjacent fissures, with 

 a total width of 9 mm. and located 19 mm. above the foramen 

 coecum. The lateral hmbs of the suture, which also diverge 

 upward, are straight regular fissures, in contrast to those on the 

 tabula externa. The right limb is 13, the left 19 mm. in length 

 and they are 16 mm. apart at their upper ends. The bony part 

 included by the suture is narrower but higher on its inner side 

 than on the outer. On a horizontal section through the frontal 



Fig. 3 Frontal bone of the skull in tigure 2 seen from the inside (upper part 

 sawed off). 



bone, at a level somewhat above the transverse portion of the 

 abnormal suture, a trapezium is formed by the lateral limbs, with 

 its shorter base directed inward. This wedge-shaped piece of 

 bone is plainly shown in Rauber's section of a similar case. 



Schwalbe directed attention to the fact that adult skulls 

 showing remnants of a fontanella metopica present an unusually 

 large interorbital breadth. Table 2 is a compilation of tables 

 by Schwalbe and Fischer with Rauber's case and that of the 

 author, in which the interorbital breadths and the interorbital 

 indices are given. The interorbital index represents the relation 

 between the interorbital breadth and the internal biorbital 



