180 A MANUAL OF DENTAL ANATOMY. 



former rising to the level of the alveolar margins of the 

 jaws. At this period the crypts or alveoli are not arranged 

 in a perfectly uniform line, nor are they all equally complete. 

 The septa, which divide into a series of cells that which at 

 an earlier age was but a continuous groove, are less perfect 

 at the back than at the front part of the mouth. The 

 alveoli of the central incisors of the upper and the lower 

 jaws are a little larger within than at the orifice, and this 

 diiference is made still greater by a depression upon the 

 lingual wall of each for the reception of the pulp of the 

 corresponding permanent tooth. They are divided from 

 the crypts of the lateral incisors by a septum which runs 

 obliquely backwards and inwards towards the median line. 

 The sockets for the lateral incisors occupy a position slightly 

 posterior to those for the central teeth, and are divided 

 from the canine alveoli by a septum which proceeds obliquely 

 backwards, and in the lower jaw, as regards the median line 

 of the mouth, outwards. By the arrangement of these 

 divisions the alveoli of the central incisors are rendered 

 broader in front than behind, and the relative dimensions 

 of the sockets of the lateral teeth are reversed, as shown in 

 Fig. 77. The crypts of the canine teeth are placed a little 

 anteriorly to those of the laterals, and nearly in a line with 

 those of the central incisors, giving to the jaws a somewhat 

 flattened anterior aspect." 



While the main bulk of the lower jaw is made up by the 

 alveoli of the teeth, in the upper jaw the alveoli descend 

 but little below the level of the palatal plates, though the 

 sockets are tolerably deep. The antrum as a special distinct 

 cavity cannot be said to exist, being merely represented by 

 a depression upon the wall of the nasal cavity, the alveolar 

 cavities therefore being separated only by n thin plate of 

 bone from the orbits. 



The figure represents also the extent to which calcification 

 has advanced in the various teeth. 



