TEMPORAL AND INFRATEMPORAL REGIONS 277 



border of the masseter also, to reach the outer surface of the 

 buccinator muscle. There it unites with branches of the 

 facial nerve to form the buccal plexus, from which branches are 

 distributed to the mucous membrane and skin of the cheek. 



The buccinator nerve is a sensory nerve, and all the sensory 

 fibres in the anterior division of the mandibular nerve 

 enter into its composition, A few motor fibres, however, 

 are also prolonged into it; these come off from it in two 

 branches, viz., (i) in the nerve to the external pterygoid^ 

 which, as a rule, arises in common with the buccinator nerve ; 

 and (2) in a third twig of supply to the temporal muscle. This 

 temporal branch springs from the buccinator nerve, after it has 

 reached the lateral surface of the external pterygoid, and 

 proceeds upwards to supply the anterior part of the temporal 

 muscle (Fig. no). In some cases the buccinator nerve 

 pierces the temporal muscle instead of passing under cover of it. 

 Nervus Auriculo - Temporalis. The auriculo - temporal 

 nerve springs by two roots from the posterior division of 

 the mandibular nerve, under cover of the external pterygoid. 

 The two roots are composed of sensory fibres and each 

 receives a communication from the otic ganglion, by means of 

 which it is brought indirectly into^association with the glosso- 

 pharyngeal nerve. The roots embrace the middle meningeal 

 artery, and unite posterior to it to form a stem which runs 

 posteriorly between the neck of the mandible and the 

 spheno-mandibular ligament. At the interval between the ear 

 and mandible it turns upwards, in relation to the deep surface 

 of the parotid gland, crosses the zygoma in company with 

 the superficial temporal artery, and enters the scalp, where it 

 breaks up into terminal branches. 



Its branches are: (i) one or two strong branches of 

 communication to the temporo-facial nerve; (2) a few slender 

 filaments which enter the posterior aspect of the temporo- 

 mandibular joint ; (3) some twigs to the parotid gland ; (4) 

 terminal filaments to the skin over the temporal region and 

 summit of the head; (5) auricular branches. 



The auricular branches are usually two to the skin lining 

 the interior of the external meatus, and two to the integument 

 over the upper and anterior part of the auricle. The former 

 gain the interior of the meatus by passing between the osseous 

 and cartilaginous portions of the canal. 



Nervus Alveolaris Inferior. The inferior alveolar nerve 

 n18 b 



