276 INTERNAL MAXILLARY ARTERY. 



jaw ; next, curves around the lower border of the external pterygoid 

 muscle near its origin, and ascends obliquely forwards upon the 

 outer side of that muscle ; it then passes between the two heads of 

 the external pterygoid and enters the pterygo-maxillary fossa. Occa- 

 sionally it passes between the two pterygoid muscles, without appear- 

 ing on the outer surface of the external pterygoid. In consideration 

 of its course this artery may be divided into three portions : maxillary, 

 pterygoid, and spheno-maxillary. 



Relations. The Maxillary portion is situated between the ramus 

 of the jaw and the internal lateral ligament, lying parallel with the 

 auricular nerve ; the pterygoid portion between the external ptery- 

 goid muscle, and the masseter and temporal muscle. The pterygo- 

 maxillary portion lies between the two heads of the external ptery- 

 goid muscle, and in the spheno-maxillary fossa is in relation with 

 MeckePs ganglion. 



Branches. 



f Tympanic, 



,, . .. ) Inferior dental, 



Maxillary portion 1 Arteria meningea magn&j 



' Arteria meningea parva. 



Deep temporal branches, 

 External pterygoid, 



Pterygoid portion <^ Internal pterygoid, 

 Masseteric, 

 Buccal. 



Superior dental, 

 Infra-orbital, 



Pterygo-maxillary } Pterygo-palatine, 

 portion j Spheno-palatine, 



Posterior palatine, 

 Vidian. 



The Tympanic branch is small and not likely to be seen in an 

 ordinary dissection ; it is distributed to the temporo-maxillary articu- 

 lation and meatus, and passes into the tympanum through the fissura 

 Glaseri. 



The Inferior dental descends to the dental foramen, and enters 

 the canal of the lower jaw in company with the dental nerve. 

 Opposite the bicuspid teeth it divides into two branches, one of 

 which is continued onwards within the bone as far as the symphysis, 

 to supply the incisor teeth, while the other escapes with the nerve 

 at the mental foramen, and anastomoses with the inferior labial and 

 submental branch of the facial. It supplies the teeth of the lower 

 jaw, sending small branches along the canals in their roots. 



The Arteria meningea magna ascends behind the temporo-maxil- 

 lary articulation to the foramen spinosum in the spinous process of 

 the sphenoid bone, and entering the cranium divides into an anterior 

 and a posterior branch. The anterior branch crosses the great ala 



