THE TRIGEMINAL NEKVE 



799 



the pterygoideus medialis and the guttural pouch, and on reaching the lateral 

 surface of the pterygoideus lateralis, it divides into two terminal branches— the 

 inferior alveolar and lingual nerves. It gives "off the following branches: 



1. The masseteric nerve (N. massetericus) (Figs. 562, 646) passes outward 

 through the sigmoid notch of the mandible across the anterior surface of the tem- 

 poro-mandibular articulation and enters the deep face of the masseter muscle, in 

 which it ramifies. 



2. The deep temporal nerves (Nn. temporales profundi) (Fig. 562), two or 

 three in number, arise from, or by a common trunk with, the masseteric. They 

 supply the temporalis muscle. 



3. The buccinator nerve (N. buccinatorius) passes downward and forward 

 at first across the medial surface of the temporo-mandibular articulation, then 

 through the anterior part of the lateral pterygoid muscle, then between the bucci- 



Fig. 647. — Deep Dissection of Base of Cranium, Viewed from the Right and Below. 

 The tympanic cavity is opened and the paramastoid process is sawn off. a, Occipital condyle ; ^, body of sphenoid; 

 c, external acoustic meatus (part removed) ; rf, malleus; e, incus; i, stump of ophthalmic nerve; ^, stump of maxillary 

 nerve; 5, sphenopalatine plexus: 4. nerve of pterygoid canal; 4'. deep petrosal nerve; A" , branch to tympanic plexus; 

 4'", superficial petrosal nerve; 5, superficial temporal nerve (cut off); 6, masseteric nerve (cut off); 7, mandibular 

 nerve (raised); 5, lingual nerve (cut off); 9, pterygoid nerve (cut); 10, nerve to tensor tympani; 11, otic ganglion; 

 i .3, facial nerve; 75, stapedial nerve; ?4, chorda tympani; iJ, glosso-pharyngeal nerve (cut) ; J^, tympanic nerve; 17, 

 vagus (cut off); 18, auricular branch of vagus: 19, spinal accessory nerve (cut off); ZO, hypoglossal nerve (cut off; 

 21 , sympathetic nerve (cut off) ; 22, internal carotid artery. (After Ellenberger, in Leisering's Atlas.) 



nator vein and the tuber maxillare (Fig. 646). It continues forward in the sub- 

 mucous tissue of the cheek along the ventral border of the depressor labii inferioris 

 and divides into branches which ramify in the mucous membrane and glands of the 

 lips in the vicinity of the commissure. It supplies small branches to the lateral 

 pterygoid and temporal muscles and detaches numerous collateral twigs to the 

 mucous membrane of the cheek and to the buccal glands. It also communicates 

 with the inferior buccal branch of the facial nerve. 



4. The pterygoid nerve (N. pterygoideus) arises in common with the preceding, 

 passes doAvnward and forward under cover of the parent trunk, and divides into 

 branches which enter the posterior part of the pterygoideus medialis at the division 

 between the two layers of the muscle (Fig. 647). 



The otic ganglion (G. oticum) is situated on the mandibular near the origin of 

 the buccinator nerve, and is related medially to the tensor palati and the Eustachian 

 tube. It receives motor fibers from the pterygoid nerve and sensory fibers by the 



