THE PERIPHERAL NERVOUS SYSTEM. 375 



/. N. alveolaris inferior (Fig. 154, d). — This passes 

 toward the mandibular foramen, but before reaching it gives 

 off a branch to the mylohyoid and digastric muscles. It then 

 enters the foramen, passes through the mandibular canal, and 

 gives numerous inferior dental branches to the teeth. At the 

 mental foramen (or foramina) it passes out of the canal and 

 divides into several mental nerves, to the chin, lower lip, and 

 mucosa of the lower jaw. 



g. N. lingualis (hig. 154, /;).— The lingual nerve passes 

 between the internal and external pterygoid muscles, and two 

 or three millimeters from its origin it receives the chorda tym- 

 pani nerve (t), a communicating branch from the facial (see 

 page 376). It passes onto the ventral surface of the external 

 pterygoid, thence onto the side of the tongue, beneath the 

 mylohyoid. On the side of the tongue it divides into branches 

 which enter the tongue and are distributed to its mucous mem- 

 brane. One branch passes to the mucosa of the pharynx. 

 Just before entering the tongue a branch is given off to the 

 sublingual and submaxillary glands. 



VI. N. ABDUCENS. — The sixth nerve, the abducens, arises 

 from the medulla, as already described (Fig. 138, VI, and page 

 347). It passes into the orbit through. the orbital fissure, then 

 extends obliquely cranioventrad along the medial surface of 

 the lateral rectus muscle (Fig. 154, /'). At about the middle 

 of the length of the muscle it divides into two or three branches 

 which enter at once into the lateral rectus and supply it. 



VII. N. FACIALIS (Fig. 155). — The seventh or facial nerve 

 arises from the trapezium at the caudal margin of the pons, 

 craniad of the origin of the eighth nerve, as described in the 

 account of the brain (Fig. 138, VII). It passes into the 

 internal auditory meatus, traverses the facial canal through the 

 petrous bone, and emerges at the stylomastoid foramen. 



Within the facial canal the nerve bears an enlargement, 

 the ganglion geniculi. It gives off within the canal a branch 

 to the stapedius muscle, and the superficial petrosal and 

 chorda tympani nerves. 



The superficial petrosal (N. petrosus superficialis major) 

 nerve passes into the hiatus facialis, through the canal which 



