62 



OSTEOLOGY 



anterior inferior angle, and from the central and posterior part of the lower 

 border of the bone. Along the upper margin is part of a shallow groove, which, 

 when joined to the opposite parietal, forms a channel for the superior longitudinal 

 sinus, the elevated edges of which afford attachment to the falx cerebri. Near 

 the groove are seen several depressions; they lodge the Pacchionian bodies. 

 The internal opening of the parietal foramen is also seen when that aperture 

 exists. 



Fig. 25. Left Parietal Bone : External Surface. 



'Wr: .#* Temporal .# 



^i,: --' "- 



Borders. The superior, the longest and thickest, is dentated to articulate with 

 its fellow of the opposite side, forming the sagittal suture. The inferior is 

 divided into three v parts ; of these, the anterior is thin and pointed, bevelled at the 

 expense of the outer surface, and overlapped by the tip of the great wing of the 

 sphenoid; the middle portion is arched, bevelled at the expense of the outer 

 surface, and overlapped by the squamous portion of the temporal ; the posterior 

 portion being thick and serrated for articulation with the mastoid portion of the 

 temporal. The anterior border, deeply serrated, is bevelled at the expense of the 

 outer surface above, and of the inner below ; it articulates with the frontal bone, 

 forming the coronal suture. The posterior border, deeply denticulated, articulates 

 with the occipital, forming the lambdoid suture. 



Angles. The anterior superior, thin and pointed, corresponds with that portion 

 of the skull which in the foetus is membranous, and is called the anterior fon- 

 tanelle. The anterior inferior angle is thin and lengthened, being received in the 

 interval between the great wing of the sphenoid and the frontal. Its inner 

 surface is marked by a deep groove, sometimes a canal, for the anterior branch of 

 the middle meningeal artery. The posterior superior angle corresponds with the 

 junction of the sagittal and lambdoid sutures. In the foetus this part of the skull 

 is membranous, and is called the posterior fontanelle. The posterior inferior 



