THE INFERIOR MAXILLARY. 59 



and slightly forward, forming an angle of about 15 

 degrees with a transverse line bisecting the two glenoid 

 cavities. It is about three-fourths of an inch trans- 

 versely, one-fourth of an inch antero-posteriorly. It is 

 slightly convex from side to side, and strongly convex 

 from front to back. The articular surface extends down- 

 ward upon the posterior border of the process, and deeper- 

 internally than externally. Below the articulating sur- 

 face, anteriorly, is a depression at which the external 

 pterygoid is inserted, and lower down the bone becomes 

 somewhat constricted, forming the neck. The posterior 

 surface of the process is convex from side to side and 

 from above downward. The posterior border is slightly 

 concave from above downward ; it is smooth and rounded, 

 and directed downward and somewhat forward. The 

 inferior border is the continuation of the lower border of 

 the body; at the junction with the posterior border it 

 forms an angle which is markedly obtuse in infancy 

 and old age ; in the adult, between twenty and fifty 

 years, it approximates a right angle. The posterior 

 border of the angle gives attachment to the stylo- 

 maxillary ligament. 



The inferior maxillary develops by two principal 

 centres, one for each half, which meet and join at the 

 symphysis, forming one bone. The shape and general 

 appearance of the inferior maxillary differ at different 

 periods of life ; thus, at birth it consists of two halves, the 

 angle is very obtuse, and the alveolus is undeveloped, 

 although it contains the sockets of the temporary teeth 

 and the germs of the permanent set. In the adult the 

 angle is nearly a right angle, all the ridges and processes 

 are strongly denned and developed, the alveolar process 

 is strong and complete, constricting the necks of the 

 teeth. In old age the bone recedes and approximates its 



