156 



A MANUAL OF ANATOMY 



Anterior 



parietals and the superior angles of the two halves of the frontal. 

 It is large and diamond-shaped, and it is not completely closed, 

 as a rule, until towards the end of the second year. The posterior 

 fontanelle is situated between the postero-superior angles of the 

 parietals and the superior angle of the occipital. /It is small and 

 triangular, and is usually closed at, or shortly after, birth, but the 

 surrounding bones are still movable. The antero-lateral and 

 postero-lateral fontanelles correspond with these angles of the 

 parietal. The antero-lateral is situated between the parietal, 



sphenoid, frontal, and 

 squamous portion of the 

 temporal, whilst the 

 postero-lateral is situated 

 between the parietal, occi- 

 pital, and mastoid portion 

 of the temporal. For the 

 sagittal fontanelle of the 

 earlier part of foetal life, 

 see p. 63. 



The skull increases 

 rapidly in sire during the 

 first six years, and a 

 further marked increase 

 commences on the ap- 

 proach of puberty, wh:ch 

 is associated with the 

 development of the air 

 sinuses. The latter in- 

 crease affects chiefly the 

 frontal and facial regions. 

 In old age the cranial 

 bones become thinne r, 

 the air sinuses under- 

 go enlargement, and the 

 sutures show indications 

 of obliteration. 



Characters of the 

 Female Skull. — The bones 

 are smaller and smoother than in the male. The mastoid processes, 

 superciliary ridges, and glabella are less prominent. The frontal 

 and occipital regions are not so well developed relatively to the 

 parietal. The cranial capacity is rather less. The face as a rule 

 is narrower, and bears a smaller proportion to the cranium. 



Posterior 



Fig. 87. — The Skull at Birth, showing the 

 Anterior and Posterior Fontanelles, 

 AND the Parietal Eminences. 



Racial Peculiarities of the Skull. 



In comparing the skulls of different races attention has to be directed to the 

 following points : the capacity of the cranium, its circumference, its relative 

 length, breadth, and height, the degree of forward elongation of the jaws, and 

 the shape of the anterior nasal and orbital apertures. The cranial capacity 

 may be ascertained by filling the skull with shot, or various kinds of seeds, an 



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