354 PRACTICAL ANATOMY. 



corner rounded, and by this peculiarity we can distin- 

 guish to which side the tooth belongs ; the cutting edge 

 is convex ; when first erupted three cusps are noticeable 

 on it, which correspond to the cornua of the pulp, and 

 are gradually worn off by usage; on the lingual sur- 

 face we find three ridges corresponding to these cusps ; 

 on the same surface, near the neck, is usually a small 

 prominence called the cingulum, and beneath a depres- 

 sion termed the basilliar pit ; the termination of the 

 enamel on the gum line is concavo-convex, the former 

 on the approximal surfaces, the latter on the labial and 

 lingual ; the roots are conical in shape. 



The upper centrals are distinguished from the upper 

 laterals in that the root of the former is irregularly 

 rounded, while the latter is slightly flattened. It is also 

 one-third larger than the lateral. The mesial surface of 

 the lateral is often slightly concave and the distal more 

 convex, that corner being also more rounded and the cin- 

 gulum more marked and nearly always present; indeed, 

 it is more frequently found in the upper laterals than any 

 other teeth. 



The lower incisors differ from the upper in being 

 smaller, the cutting edges straight, and the angles at 

 both mesial and distal corner equally well defined, in 

 having no cingulum, and the roots are flat and longer in 

 comparison to the crown than the upper. 



The lower centrals and laterals are very much alike, 

 except that the former is the smaller of the two. 



The cuspids are thicker, stronger, and in every way 

 larger than the incisors. The upper has three ridges, 

 prominently marked, especially the central one, which 

 divides the labial surface. The mesial surface is larger 

 than the distal; the lingual surface is concave, excepting 

 for a prominent ridge, which makes it appear almost 



