PART SECOND. 



CHAPTEK I. 



PASSIVE ORGANS OF THE HEAD. 

 THE BONES. 



THE head is divided into cranium and face. The former 

 consists of eight distinct bones: one frontal, two parie- 

 tal ; one occipital, two temporal, one ethmoid, and one 

 sphenoid. These, when united, in consequence of their 

 peculiar form, strength, and structure, are well adapted to 

 receive the brain, and guard it from injury. 



The face has fourteen bones: two superior maxillary, two 

 malar, two palatal, two lachrymal, two nasal, two inferior 

 turbinated, one vomer, and one inferior maxillary bone. 

 These contain most of the organs of sense. 



SECTION I.' 

 BONES OF THE CRANIUM. 



Frontal Bone(os frontis.) The frontal bone (Fig. 33) 

 is situated at the anterior and upper part of the cra- 

 nium. Its form is semi-circular. Its division is into two 

 parts, the superior or frontal, and the inferior or orbital. 

 The frontal portion has two surfaces, an external and in- 

 ternal. The external surface is anterior, smooth and convex. 

 Along the median line there is an elevation, not always dis- 

 tinct, corresponding to the original separation of the foetal 

 bone, into two equal parts, by the frontal suture, which 

 sometimes continues in the adult bone. At the lower part of 

 this line of division, is the nasal prominence, which termin- 

 ates in a rough edge, for articulating with the nasal process 

 of the superior maxillary and nasal bones. The nasal spine 

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