THE TRIGEMINAL NERVE. 



1243 



notch of the mandible to enter the posterior portion of the mesial surface of the 

 masseter. It supplies one or two filaments to the temporo-mandibular articulation. 



2. The external pterygoid nerve (n. pterygoideus externus) (Fig. 1063), 

 usually takes its origin as a common trunk with the buccal nerve. It enters the 

 deep surface of the external pterygoid. 



3. The deep temporal nerves (nn. temporales profundi anterior et posterior) 

 (Fig. 1063), are usually three or two in number. The anterior accompanies 

 the buccal nerve between the heads of the external pterygoid, after which it passes 

 upward to supply the anterior portion of the temporal muscle. The middle passes 

 outward across the upper margin of the external pterygoid and then upward close 

 to the bone to enter the deep surface of the temporal muscle. It often fuses with 

 either the anterior or posterior deep temporal, thus reducing the number of temporal 



FIG. 1062. 



Gasserian ganglion 

 V. nerve, sensory root 



Maxillary division V. nerve 



Mandihular 

 division V.n< 



Auriculo- 

 *emporal n< 

 Mandib. div. V. 

 nerve, partly cut' 

 Chorda tympani 

 Otic ganglion ; its 

 br. to tensor ty 

 pani is seen above 

 the leadei 

 Middl 

 meningeal artery 



Part 

 parotid gland 



'Spheno-palatine 



Posterior 

 superior dental 



Br. from otic ganglion 

 to auriculo-temp. nerve' 



Br. from otic gang, to chorda tympani 



Int. pterygoid nerve 



Int. pterygoid muscle 



Buccinator 

 muscle 



Inferior dental ne 



Lingual br. V. nerve 



Dissection showing lateral view of spheno-palatine and otic ganglia. 



nerves to two. The posterior frequently accompanies the nerve to the masseter for 

 a variable distance, after which it turns upward along the bone to enter the deep 

 surface of the posterior portion of the muscle. 



4. The buccal nerve (n. buccinatorius) (Fig. 1062) is purely sensory. It 

 arises in common with the external pterygoid and anterior deep temporal nerves 

 and is accompanied by the latter between the heads of the external pterygoid. 

 Passing downward on the inner side of the temporal muscle it reaches the outer 

 surface of the buccinator, where it breaks up into several branches which form a 

 plexus around the facial vein, with the buccal branch of the facial nerve. Some of 

 its branches pierce the buccinator muscle to supply the mucous membrane of the 

 cheek as far forward as the angle of the mouth, while the others supply the skin of 

 the cheek. 



Variations. Instead of lying to the inner side, the nerve may pierce the temporal muscle. 

 It may be derived from the posterior superior dental nerve or from the inferior dental in the 

 latter instance emerging from the inferior dental canal by a small foramen m the alveolar border 



