Bones of the Skuli. 



63 



Fonticulus frontalis 



Fonticulus frontalis 



Fonticulus 

 occipitalis 



Fonticulus mastoideus 



Fonticulus sphenoidalis 



Fonticulus occipitalis 



76 and 77. Skull of the new born child, magnification i : 2. 



View from above. View from the right. 



A part of the bones of the skull are originally laid down in cartilage and represent 

 the primordial cranium (chondro-cranium) ; these are the os occipitale (without the upper part 

 of the squama), the os sphenoidale, the os temporale (without the squama and the pars tym- 

 panica), the os ethmoidale, the concha nasalis inferior, the os hyoideum and the small bones 

 of the ear. All other bones of the skull, as, well as the upper part of the squama occipitalis, 

 the squama temporalis and the pars tympanica oss. temporalis arise as roof bones (bones of 

 the vault) and parietal bones in that the bony substance forms in membrane, the membraneous 

 skull-capsule surrounding the brain above, in front, behind, and at the sides. At birth there 

 are still non-ossified remains of this membrane in the regions in which the bones of the skull 

 meet, there being narrower stripes along what are later to be the bony sutures, larger areas 

 where several bones meet with one another. These latter regions are called the fonticuli 

 (fontanelles) and are six in number; two unpaired and two paired. Of the unpaired the 

 largest, quadrangular, fonticulus frontalis [major] lies at the junction of the suturae coronalis, 

 sagittalis and frontalis, the small, triangular fonticulus occipitalis [minor] at the apex of the 

 squama occipitalis, where the suturae lambdoideae and the sutura sagittalis meet. Of the 

 paired fontanelles, the anterior, oblong fonticulus sphenoidalis lies at the apex of ^he large 

 wing of the sphenoid, bounded by the angulus parietalis of the ala magna oss. sphenoidalis, 

 by the squama temporalis oss. temporalis, the angulus sphenoidalis oss. parietalis, and the 

 squama frontalis oss. frontalis; the posterior, more irregular fonticulus mastoideus is situated 

 below the angulus mastoideus oss. parietalis, enclosed by this, by the pars mastoidea oss. 

 temporalis, and by the squama occipitalis oss. occipitalis. The fontanelles usually close during 

 the first, the fonticulus major not until the second half of the second year of life. The bones 

 of the face with the exception of parts of the mandibula also arise like the roof bones. 



