820 THE NERVES. 



the lips, along the inferior molar gland and the inferior border of the buccinator 

 muscle. 



It gives some very fine filaments to the external pterygoid, in its passage 

 across that muscle. Beyond this, it furnishes a very slender ramuscule to the 

 orbital portion of the temporal muscle — the analogue of the anterior deep temporal 

 nerve of Man. 



On the superior molar gland, it emits a fasciculus of branches to this organ 

 and the buccinator muscle. In its submucous track it throws off, at certain 

 distances, ramuscules of various sizes which go to the inferior molar gland and 

 the buccal membrane ; while its terminal filaments are expended in the lining 

 membrane and glands of the lips, near the commissure. 



The majority of the filaments given off by this nerve to the external pterygoid 

 and temporal muscles are doubtless motor, but the other ramuscules are sensitive ; 

 even those distributed to the buccinator muscle are no exception, for its sub- 

 masseteric portion is supplied by the facial, as well as the superficial or anterior 

 part. 



3. Internal Pterygoid Nerve. — It forms, with the preceding nerves, a 

 single fasciculus, which leaves the anterior part of the inferior maxillary nerve. 

 After crossing, outwardly, the internal maxillaiy artery, it descends between the 

 nervous trunk from which it emanated, and the external layer of the tensor 

 palati muscle, to go to the inner side of, and become expended in, the internal 

 pterygoid muscle. 



This nerve is the smallest branch of the inferior maxillaiy trunk, after the 

 mylo-hyoidean, and excites the contraction of the muscle receiving it. 



4. Superficial Temporal, Temporo-auricularis, or Subzygomatic 

 Nerve (Figs. 453, 8 ; 459, 3) — This arises from the inferior maxillary nerve, 

 at the opposite side of the fasciculus formed by the three preceding branches, or 

 posteriorly. Placed at first at the inner side of the temporo-maxillary articu- 

 lation, and between it and the guttural pouch, it is afterwards directed down- 

 wards and outwards, passes between the parotid gland and the posterior border 

 of the inferior maxilla, and below the condyle ; it then bends round the neck of 

 that bony eminence to arrive beneath, and to the outside of, the precited articu- 

 lation, where it terminates by anastomosing with the facial nerve. 



In its course it sends off numerous fine filaments to the guttural pouch, the 

 parotid gland, and the integuments of the temporal region. Among the latter, 

 it is necessary to notice more particularly those which accompany the superficial 

 temporal artery. 



This nerve appears to be exclusively sensitive. Section of it, before it anas- 

 tomoses with the facial nerve, does not really prevent contraction of the muscles 

 which receive the divisions of the plexus formed by this anastomosis. 



5. Lingual or Gustatory Nerve (Figs. 453, 10 ; 459, 5). — The gustatory 

 nerve — the principal branch of the inferior maxillary trunk, which it almost 

 equals in volume — is detached at an acute angle from the anterior border of 

 that nerve shortly after its exit from the pterygoid muscles. To accomphsh 

 its course, which it effects in describing a slight cm-ve with concavity antero- 

 posterior, it is directed forwards and downwards, passing between the internal 

 pterygoid muscle and the branch of the inferior maxillary bone, and gaining the 

 base of the tongue, where it is situated beneath the buccal mucous membrane. 

 It afterwards descends more deeply, between the mylo-hyoid and hyo-glossua 

 longus muscles, turns round the inferior border of the latter — including also 



