TEMPORAL AND INFRATEMPORAL REGIONS 181 



muscle (Fig. 63). In some cases the buccinator nerve pierces 

 the temporal muscle instead of passing under cover of it. 



The posterior division of the mandibular nerve consists 

 mainly of sensory fibres, but it still contains a few motor 

 fibres which ultimately pass into its alveolar branch and 

 thence to the mylo-hyoid nerve. 



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 

 backwards 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 antero-medial 

 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 (Fig. 51). 



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

 communication to the upper division of the facial nerve; (2) 

 a few slender filaments which enter the posterior aspect of 

 the 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 upper part of 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 

 (O.T. inferior dental) is the largest branch of the posterior 

 division of the mandibular nerve. It emerges from under 

 cover of the external pterygoid, at the lower border of the 

 muscle, passes downwards along the lateral surface of. the 

 spheno-mandibular ligament, and enters the mandibular fora- 

 men. The inferior alveolar artery runs downwards posterior 

 to it, whilst the lingual nerve is anterior to it and upon a 

 somewhat deeper plane. The inferior alveolar is a sensory 

 nerve, but a few fibres from the motor root are prolonged 

 downwards within its sheath as far as the mandibular foramen. 



in 12 b 



