158 



THE SKELETON. 



Fig. 110. Eight Nasal Bone. 



Frontal B* 



Opposite* 



either side of the sagittal suture, in the place of the parietal foramen. There is a specimen 

 precisely similar to this in the Museum of St. George's Hospital; and another, in which a 

 small circular gap exists in the parietal bone of a young child, just above the parietal eminence. 

 Similar deficiencies are not unfrequently met with in hydrocephalic skulls ; being most frequent, 

 according to Dr. Humphry, in the frontal bones ; and, in the parietal bones, on either side of 

 the sagittal suture. 



BONES OF THE FACE. 



The Facial Bones are fourteen in number, viz., the 

 Two Nasal, Two Palate, 



Two Superior Maxillary, Two Inferior Turbinated, 



Two Lachrymal, Vomer, 



Two Malar, Inferior Maxillary. 



NASAL BONES. 



The Nasal 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 con- 

 cave from above down- 

 wards, convex from side 

 to side ; it is covered by 

 the Pyramidalis and 

 Compressor nasi mus- 

 cles, marked by numer- 

 ous small arterial fur- 

 rows, and perforated 

 about its centre by a 

 foramen, sometimes 

 double, for the trans- 

 mission of a small "vein. 

 Sometimes this foramen is absent on one or both sides, and occasionally the 

 foramen ccecum opens on this surface. The inner surface is concave from 

 side to side, convex from above downwards; in which direction it is tra- 

 versed 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 backwards, 

 and serves for the attachment of the lateral cartilage of the nose. This border 

 presents about its centre a notch, through which passes 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, articu- 

 lates with its fellow of the opposite side, and is prolonged behind into a ver- 

 tical 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 vertebra?. 



Articulations. With four bones. Two of the cranium, the frontal and eth- 

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

 No muscles are directly attached to this bone. 



Outer Surface-. 



Fig. 111. Eight Nasal Bone. 



itntn 



Fro ntal Sfpine- 

 crest 



>J3 rpcrifli^'iUMT 

 /Plate nf Ethmoid. 



groove fo r iiti'Stil nc rvc 

 Inner Surface 



