Chap. V] 



THE SKELETON 



59 



Fig. 30. — Skull of Xew-born Child. 

 To show moulding. (Edgar.) 



ossified, they are readily moulded, and they overlap one another 

 more or less during parturition. The spaces at the angles of the 

 bone occupied by the membra- 

 nous tissue are termed the fon- 

 tanelles, so named from the 

 pulsations of the brain, which 

 can be seen in some of them and 

 which the early anatomists lik- 

 ened to the rise and fall of water 

 in a fountain. There are six of 

 these fontanelles. 



Anterior Fontanelle. — The 

 anterior fontanelle is the larg- 

 est, and is a lozenge-shaped 

 space between the angles of the 

 two parietal bones and the two segments of the frontal bone. It 

 remains open until the second year, and occasionally persists 

 throughout life. 



Posterior Fontanelle. — The posterior fontanelle is much smaller 

 in size, and is a triangular space between the occipital and two 

 parietal bones. This is closed by an extension of the ossifying 



process a few months after birth. 

 (See Figs. 61 and 62.) 



The other four fontanelles, two 

 on each side of the skull, are 

 placed at the inferior angles of 

 the parietal bones ; they are un- 

 important. Small, irregular os- 

 sicles called sutural bones (Wor- 

 mian bones) are found in the 

 sutures of the head, chiefly near 

 the fontanelles, and often assist 

 in the closure of the fontanelles. 

 Sinuses of the head. — Four 

 sinuses communicate with each 

 nasal cavity : the frontal, ethmoid, sphenoid, and maxillary or an- 

 trum of Highmore. The mucous membrane which lines the nose 

 also lines all of these sinuses, and inflammation of this membrane 

 may extend into any of them and cause sinusitis. (See Fig. 90.) 



Fig. 31. — Skull of New-born Child 

 To show moulding. (Edgar.) 



