36 



PRACTICAL ANATOMY. 



THE NASAL BONES. 



The nasal are two small, quadrilateral, flat bones, 

 which are placed in the middle line of the skull, below 

 the frontal, and form the bridge of the nose. They 

 present for examination four borders and two surfaces. 

 The superior border is short, thick, and serrated for 

 articulation with the internal angular process of the 

 frontal. The inner border is slightly beveled at the 

 expense of its inner surface ; it is thicker above than 

 below, and articulates in the middle line with its fellow. 

 The external border is thin and rough and is strongly 

 curved, and articulates with the superior maxillary bone. 



Frontal B. 



1U. 



with 



Tro-ntal ffjriru. 



yroove for itatal nerve 

 (Outer surface.) (Inner surface.) 



FIG. 15. NASAL BONES. 



The inferior border is thin and sharp, and often irregular 

 (" frayed out "). The external surface is smooth, and 

 perforated by a few small foramina ; it is concave from 

 above downward, convex from side to side. The inter- 

 nal surface is concave from side to side, convex from 

 above downward ; it presents a slight sinuous groove, 

 passing from the superior to the inferior border, for the 

 nasal nerve. The posterior lip of the inner border is 

 prominent, and forms, with its fellow, the nasal crest for 

 articulation with the spine of the frontal bone and the 

 vertical plate of the ethmoid. The nasal bone develops 

 from one centre, which appears about the second month. 



