218 



FACE. 



which connect its different parts to each other 

 and to the cranium. The lightness of the face 

 depends upon the thinness of some of its 

 bones, and the large cavities which it com- 

 prises. The two upper maxillary bones form 

 by their alveolar border and palatine arch a 

 strong platform, from which ascend five osseous 

 pillars; one median, formed by the vomer and 

 the perpendicular plate of the ethmoid; two 

 at the sides of the nose, formed by the nasal 

 process of the superior maxilla ; and at 

 the lateral parts of the face two others, 

 formed by the malar processes of the upper 

 jaw and the malar bones. All these pillars 

 connect the upper jaw with the bones of the 

 cranium, and contribute by their form, strength, 

 or extent of articulation to resist or diffuse the 

 concussion of violent blows applied to the face. 

 The strength of the lower jaw depends upon 

 its arched form and upon its mobility, but, 

 from its exposed situation, it is notwithstand- 

 ing frequently broken. 



Development of the face. The development 

 of the face consists not merely in its general 

 increase, but in the relative proportion of its 

 several parts at different periods of life. As 

 the face contains the organs of sight, smell, 

 and taste, together with those of mastication, 

 we shall not expect to find it much deve- 

 loped in the foetus and infant while these 

 parts are scarcely called into action ; accord- 

 ingly, we observe the vertical diameter of the 

 face (strictly so called) to be very short, which 

 is owing to the slight elevation of the ethmoid, 

 the lachrymal, the upper and the lower maxil- 

 lary bones, consequent on the imperfect deve- 

 lopment of the nasal cavities, the maxillary 

 sinuses, and the teeth; see Jig. 131. The 



orbits, indeed, are remarkably large, but this 

 depends upon the great development of the 

 cranium and the breadth of the orbitar plates 

 of the frontal bones, for in their vertical dia- 

 meters the orbits are not remarkable at this 

 period of life. 



The transverse diameter of the face in the 

 fetus is considerable across the orbits, but 

 below these it is narrower in proportion than in 

 the adult. The other chief peculiarities of the 

 foetal face are, the small size of the nasal cavi- 

 ties, the absence of the canine fossae, depend- 

 ing partly on the small vertical diameter of the 

 upper jaw, and partly upon the teeth being 

 still lodged within it; the prominence and 

 shortness of the alveolar borders of both jaws, 

 the vertical direction of the symphysis menti, 

 which even inclines from above downwards 

 and a little backwards; the remarkable con- 



vexity of the maxillary tuberosities, owing to 

 the teeth being lodged within them ; and the 

 great obliquity from above downwards and 

 forwards of the posterior apertures of the nose, 

 arising from the smallness of the maxillary 

 sinuses ; the small antero-posterior diameter of 

 the palatine arch, which depends upon the 

 same cause; and, finally, the oblique direction 

 of the rami of the lower jaw: see Jig. 377, 

 vol. i. p. 742. 



In the adult, as the ethmoid and turbinated 

 bones together with the maxillary sinuses 

 become developed, the nasal cavities enlarge, 

 especially in their vertical diameter; above, 

 they communicate with the frontal sinuses, 

 which are now fully formed and projecting ; 

 the jaws have become deeper from the protru- 



Fig. 132. 



sion of the teeth, which cause a considerable 

 addition to the vertical diameter of the face ; 

 below, the palatine arch has extended back- 

 wards with the development of the maxillary 

 sinuses, and the posterior apertures of the nose 

 have become in consequence nearly vertical : 

 the rami of the lower jaw form also nearly 

 a right angle with its body. 



In old age the vertical diameter of the face 

 decreases in consequence of the loss of the 

 teeth and the contraction of the alveolar borders 

 of the jaws, which touch each other when the 

 mouth is closed ; the rami of the jaw resume 

 the oblique direction of childhood, (Jig. 133;) 



Fig. 133. 



