SUPERIOR MAXILLARY BONE. 



81 



Fig. 43. Right Nasal Bone. 



Fig. 44. Right Nasal Bone. 



witA Frontal B. 



until 



Outer Surface-. 



NASAL BONES. 



The Nasal Bones are two small oblong bones, varying in size and form in different 

 individuals ; they are placed side by side at the middle and upper part of the face, 

 forming, by their junction, the "bridge" of the nose. Each bone presents for 



examination two sur- 

 faces, and four borders. 



The outer surface is 



concave from above 



downwards, convex 



from side to side ; it is 



covered by the Com- 



ijl J Opposite bone. pressor naris muscle, 

 3U is* marked by numerous 



small arterial furrows, 



and perforated about 



its centre by a foramen, 



sometimes double, for 



the transmission of a 



small vein. Sometimes 



this foramen is absent 



on one or both sides, and occasionally the foramen caecum opens on this surface. 

 The inner surface is concave from side to side, convex from above downwards ; in 

 which direction it is traversed by a longitudinal groove, sometimes a canal, for 

 the passage of a branch of the nasal nerve. The superior border is narrow, thick, 

 and serrated for articulation with the nasal notch of the frontal bone. The inferior 

 border is broad, thin, sharp, directed obliquely downwards, outwards, and back- 

 wards, and serves for the attachment of the lateral cartilage of the nose. This 

 border presents about its centre a notch, which transmits the branch of the nasal 

 nerve above referred to ; and is prolonged at its inner extremity into a sharp 

 spine, which, when articulated with the opposite bone, forms the nasal angle. 

 The external border is serrated, bevelled at the expense of the internal surface 

 above, and of the external below, to articulate with the nasal process of the superior 

 maxillary. The internal border, thicker above than below, articulates with its 

 fellow of the opposite side, and is prolonged behind into a vertical crest, which 

 forms part of the septum of the nose ; this crest articulates with the nasal spine 

 of the frontal above, and the perpendicular plate of the ethmoid below. 



Development. By one centre for each bone, which appears about the same period 

 as in the vertebrae. 



Articulations. With four bones: two of the cranium, the frontal and ethmoid; 

 and two of the face, the opposite nasal and the superior maxillary. 

 No muscles are directly attached to this bone. 



SUPERIOR MAXILLABY BONE. 



The Superior Maxillary Bone is one of the most important bones of the face in 

 a surgical point of view, on account of the number of diseases to which some of 

 its parts are liable. Its minute examination becomes, therefore, a matter of 

 considerable interest. It is the largest bone of the face, excepting the lower jaw ; 

 and forms, by its union with its fellow of the opposite side, the whole of the upper 

 jaw. Each bone assists in the formation of three cavities, the roof of the mouth, 

 the floor and outer wall of the nose, and the floor of the orbit ; enters into the 

 formation of two fossae, the zygomatic, and spheno-maxillary ; and two fissures, 

 the spheno-maxillary, and pterygo-maxillary. Each bone presents for examina- 

 tion a body, and four processes, malar, nasal, alveolar, and palatine. 



The body is somewhat quadrilateral, and is hollowed out in its interior to form 

 a large cavity, the antrum of Highmore. It presents for examination four 

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