802 



THE NERVOUS SYSTEM. 



The posterior superior dental branches arise from the trunk of the nerve just 

 as it is about to enter the infra-orbital canal ; they are generally two in number. 



Sensory root. 

 Motor root. 



Auriculo-temporal\ 

 nerve. 



FIG. 483. Distribution of the second and third divisions of the fifth nerve and submaxillary ganglion. 



but sometimes arise by a single trunk, and immediately divide and pass downward 

 on the tuberosity of the superior maxillary bone. They give off several twigs to 

 the gums and neighboring parts of the mucous membrane of the cheek (superior 

 gingival branches). They then enter the posterior dental canals on the zygomatic 

 surface of the superior maxillary bone, and, passing from behind forward in the 

 substance of the bone, communicate with the middle dental nerve, and give off' 

 branches to the lining membrane of the antrum and three twigs to each of the 

 molar teeth. These twigs enter the foramina at the apices of the fangs and 

 supply the pulp. 



The middle superior dental branch is given off from the superior maxillary nerve 

 in the back part of the infra-orbital canal, and runs downward and forward in a 

 special canal in the outer wall of the antrum to supply the two bicuspid teeth. It 

 communicates with the posterior and anterior dental branches. At its point of 

 communication with the posterior branch is a slight thickening Avhich has received 

 the name of the ganglion of Valentin ; and at its point of communication with the 

 anterior branch is a second enlargement, which is called the ganglion of Bochdalek. 

 Neither of these is probably a true ganglion. 



The anterior superior dental branch, of large size, is given off from the supe- 

 rior maxillary nerve just before its exit from the infra-orbital foramen ; it enters a 

 special canal in the anterior wall of the antrum, and, coursing from before back- 

 ward, divides into a series of branches which supply the incisor and canine teeth. 

 It communicates with the middle dental branch, and gives off a nasal branch, which 

 passes through a minute canal into the nasal fossa, and supplies the mucous mem- 



