20 



TOPOGRAPHIC AND APPLIED ANATOMY. 



suture, it does not close until the second year, but may remain open for a much longer period. 

 During the birth of the child it is utilized by the obstetrician to determine the position of the head. 

 2. The small or occipital fontanclle. This has the shape of an obtuse-angled triangle and 

 lies between the highest point of the occipital bone and the two parietal bones. During birth 

 this fontanelle is usually closed, but the physician can nevertheless recognize it by the fact that the 

 compression of the child's skull pushes the occipital bone beneath the edges of the parietal bones. 

 The paired fontanelles, less important and usually closed at birth, are: 

 i. The antero-lateral fontanelle, between the frontal and parietal bones on the one side and 

 the great wing of the sphenoid and the squamous portion of the temporal on the other. 



Scalp 



Pericranium - 



Mucous membrane 



of frontal sinus " 



Opening of frontal 



sinus 



Anterior wall of- 

 frontal sinus 



FIG. 4. The right frontal sinus opened from in front. 



2. The postero-lateral jontanelle, between the mastoid portion of the temporal, the parietal, 

 and the occipital bones. In the new-born a fissure extends from this fontanelle into the occipital 

 bone, which has been falsely attributed to the effect of traumatism, but which really marks the 

 original boundary between that portion of the occipital bone which is laid down in cartilage and 

 that which is laid down in membrane. 



The occurrence of supernumerary sutures and Wormian bones in the vault of the skull is of 

 considerable importance from a practical, and particularly from a medico-legal, standpoint, since 

 they have been mistaken for fractures. Among these may be mentioned the frequently persistent 



