734 THE NERVOUS SYSTEM. 



back part of the ganglion, being generally blended with the Vidian nerve. It 

 passes through the ptery go-palatine canal with the pterygo-palatine artery, and is 

 distributed to the mucous membrane of the upper part of the pharynx, behind the 

 Eustachian tube. 



The upper posterior nasal branches are a few twigs given off from the posterior 

 part of the ganglion, which run backward in the sheath of the Vidian nerve to 

 the mucous membrane at the back part of the roof, septum, and superior meatus 

 of the nose and that covering the end of the Eustachian tube. 



The Inferior Maxillary Nerve (Fig. 395). 



The Inferior Maxillary Nerve (n. mandibularis) distributes branches to the 

 teeth and gums of the lower jaw, the integument of the temple arid external ear, 

 the lower part of the face and lower lip, and the muscles of mastication ; it also 

 supplies the tongue with a large branch. It is the largest of the three divisions 

 of the fifth, and is made up of two roots : a large or sensory root proceeding from 

 the inferior angle of the Gasserian ganglion ; and a small or motor root, which 

 passes beneath the ganglion, and unites with the sensory root just after its exit 

 from the skull through the foramen ovale. Immediately beneath the base of the 

 skull this nerve divides into two trunks, anterior and posterior. Previous to its 

 division the primary trunk gives off from its inner side a recurrent (meningeal) 

 branch and the nerve to the Internal pterygoid muscle. 



The recurrent branch is given off directly after its exit from the foramen ovale. 

 It passes backward into the skull through the foramen spinosum with the middle 

 meningeal artery. It divides into two branches, anterior and posterior, which 

 accompany the main divisions of the artery and supply the dura mater. The 

 posterior branch also supplies the mucous lining of the mastoid cells. The anterior 

 branch communicates with the meningeal branch of the superior maxillary nerve. 



The Internal Pterygoid Nerve, given off from the inferior maxillary previous to 

 its division, is intimately connected at its origin with the otic ganglion. It is a 

 long and slender branch, which passes inward to enter the deep surface of the 

 Internal pterygoid muscle. 



The anterior and smaller division, which receives nearly the whole of the motor 

 root, divides into branches which supply the muscles of mastication. They are 

 the masseteric, deep temporal, buccal, and external pterygoid. 



The masseteric branch passes outward, above the External pterygoid muscle, in 

 front of the temporo-mandibular articulation and behind the tendon of the tem- 

 poral muscle ; it crosses the sigmoid notch with the masseteric artery, to the deep 

 surface of the Masseter muscle, in which it ramifies nearly as far as its anterior 

 border. It occasionally gives a branch to the Temporal muscle, and a filament 

 to the articulation of the jaw. 



The deep temporal branches, two in number, anterior and posterior, supply the 

 deep surface of the Temporal muscle. The posterior branch, of small size, is 

 placed at the back of the temporal fossa. It is sometimes joined with the masse- 

 teric branch. The anterior branch is frequently given off from the buccal nerve ; 

 it is reflected upward, at the pterygoid ridge of the sphenoid, to the front of the tem- 

 poral fossa. Sometimes there are three deep temporal branches ; the third branch 

 (middle deep temporal) passes outward above the External pterygoid muscle, and 

 runs upward on the bone to enter the deep surface of the Temporal muscle. 



The buccal branch passes forward between the two heads of the External 

 pterygoid, and dowmvard beneath the inner surface of the coronoid process of the 

 lower jaw, or through the fibres of the Temporal muscle, to reach the surface of 

 the Buccinator, upon which it divides into a superior and an inferior branch. It 

 gives a branch to the External pterygoid during its passage through that muscle, 

 and a few ascending filaments to the Temporal muscle, one of which occasionally 

 joins with the anterior branch of the deep temporal nerve. The upper branch 

 supplies the integument and upper part of the Buccinator muscle, joining with 



