12 



THE TONER LECTURES. 



muscle. I have ventured to call this the mitegomwn. This depres- 

 sion can be easily detected by the finger. When the antegonium is 

 well defined the mentum is always high. In a word, the vertical 

 measurement at the anterior end of the horizontal ramus being 

 large, the measurement at the posterior end is small. In one ex- 

 ample examined the anterior measurement was 3° 9"" and the pos- 

 terior 2° .S""™. In another example the anterior measurement was 

 3° and the posterior 2° 2°"°. 



Fig. 1. — The lower j;v\v, showini; the antegonivini, and high montum ; 

 a, the antegonium. (No. 200, A. N. S.) 



This variation is often met with in patients and is generally seen 

 in Cretins. It appears to be a result of rapid growth of the bone. 

 To what extent the facial artery and vein may exert pressure on 

 the bone to form the depression is not known. Tlie molar t'eeth 

 are often tilted forward in specimens of the bone which exhibit the 

 antegonium, and in some instances the teeth wear transversely in- 

 stead of obliquely. 



The finger being placed in the interval between the tongue and the 

 lower jaw-bone, one can detect with ease the mylo-hyoid ridge. The 



