THE INFERIOR MAXILLARY NERVE. 543 



temporal fossa, beneath the temporal muscle iu the substance of which 

 they are distributed. (See fig. 340.) 



The anterior branch is frequently joined with the buccal nerve, and 

 sometimes with the other deep temporal branch. 



The masseteric branch likewise passes above the external pterygoid 

 muscle, and is directed nearly horizontally outwards, through the sig- 

 moid notch of the lower jaw to the posterior border of the masseter 

 muscle, which it enters on the deep surface. It gives a filament or two 

 to the articulation of the jaw, and occasionally furnishes a branch to 

 the temporal muscle. 



The external pterygoul branch, is most frequently derived from the 

 buccal nerve. It is sometimes a separate ofFset from the smaller portion 

 of the lower maxillary nerve. 



The nerve of the infernal j^terf/ffoid muscle is closely connected at its 

 origin with the otic ganglion, and enters the inner or deep surface of 

 the muscle. 



The buccal nerve pierces the substance of the external pterygoid 

 muscle, and courses downwards and forwards to the face, in close contact 

 with the deep surface of the temporal muscle at its insertion. It fur- 

 nishes a branch to the external pterygoid muscle as it pierces it, and on 

 emerging gives two or three ascending branches to the temporal muscle. 

 It divides into two principal branches, an njrper and a to/cer, which 

 communicate with the facial nerve in a plexus round the facial vein, and 

 are distributed to the integument, the buccinator muscle, and the 

 mucous membrane. It is chiefly a sensory nerve. 



Varieties. — The buccal nerve is sometimes replaced by a branch of the infra- 

 orbital (Henle). It has been seen to arise as a branch of the inferior dental, 

 being given off from that nei-ve -vAathin the dental canal, and emerging close to 

 the alveolar border of the bone (Turner. Nat. Hist. Review, lSfi4, p. 612). Gaillet 

 (quoted by Henle) desscribes it as arising directlj^ from the Gasserian ganglion, 

 and piercing the base of the skull by a special foramen between the round and 

 oval foramina. 



Auriculo-temporal nerve. — The auriculo-temporal nerve takes its. 

 origin close to the foramen ovale. It often commences by two roots, 

 between which may be placed the middle meningeal artery. It is 

 directed at first backwards, beneath the external pterygoid muscle, to 

 the inner side of the articulation of the jaw ; then changing its course, 

 it turns upwards between the ear and the joint, covered by the parotid 

 gland ; and emerging from this place, it finally divides into two temporal 

 branches which ascend towards the top of the head. 



(a) Conunufiicati/iff hranclies. — There are commonly two branches which pass 

 forward round the external carotid artery, and join the facial nerve. Filaments 

 to the otic ganglion arise near the beginning of the nerve. 



(&) Parotid hranches are given from the nerve whUe it is covered by the gland. 



{c) Auricular brancticx. — These are two in number. The lotvcr of the two, 

 arising behind the articulation of the jaw, distributes branches to the ear below 

 the external meatus ; and sends other filaments round the internal maxillary 

 artery to join the sympathetic neiwe ; the V2)2)er branch, leaving the nerve in 

 front of the ear, is distributed in the integument covering the tragus and the 

 pinna above the extemal auditory meatus. Both are confined to the outer surface 

 of the ear. 



{cl^ Hranches to the meatus auditorius. — These, two in number, spring from the 

 point of connection of the facial and auriculo-temporal nerves, and enter the 

 interior of the auditory meatus between the osseous and cartilaginous parts. One 

 of them sends a branch to the membrana tjTnpani. 



