726 TEE NERVES. 



This nerve is remarkable for the relations it maintains with the terminal 

 ramnscules of the three branches of the ophthalmic nerve, or fifth pair. 

 Although there do not exist any real anastomoses between it and these 

 various branches, it is customary to designate the reticular mass they form 

 in front of the ear and on the side of the face, as the anterior auricular plexus. 



Terminal Bkanohks op the Facial Nerve ob Subzygomatio Plexus 

 (Fig. 110, 11, 12). — The facial nerve, as we have seen, terminates in several 

 branches, usually two, on arriving beneath the temporo-maxillary articula- 

 tion, where they join the superficial temporal nerve. After becoming sensory- 

 motor, they are continued on the external face of the masseter, covered by 

 the subcutaneous muscle of the head, to which they give some ramuscules, 

 and are united to each other by anastomosing branches of variable disposi- 

 tion, which we need not stay to examine. It is always observed with regard 

 to this arrangement, that the branches of the subzygomatio plexus, on 

 arriving near the anterior border of the masseter, are divided into a series of 

 divergent ramuscules which pass to the surface of the vascular or glandular 

 canals situated in front of the masseter, to enter the tissues of the lips, 

 cheeks, and nostrils. 



Among these ramuscules, the superior is remarkable for its great volume ; 

 it passes beneath the zygomato-labialis muscle, lies close to the inferior 

 border of the supermaxillo-nasalis magnus, beside the superior coronary 

 artei-y, and afterwards runs below the supernaso-labialis muscle, where it joins 

 the terminal ramuscules of the superior maxillary nerve, with which it is 

 distributed to the textures of the upper lip and alseof the nose (Fig. 336, 7'). 



A second ramuscule — the inferior, smaller than the preceding — follows 

 the inner aspect of the maxillo-labialis muscle, to mix by its anterior extremity 

 with the terminal fasciculus of the inferior maxillary nerve, and ramify, 

 with the proper filaments of that fasciculus, in the tissue of the lower lip. 



Between these two principal branches is a series of smaller ramifications 

 destined to the alveolo-labialis muscle. Among these are some which 

 become inflected on the inner face of the masseter, and reach the deep 

 portion of the buccinator, where they anastomose with the filaments of the 

 buccal nerve. Other ramuscules, situated below the principal inferior 

 branch, are expended in the subcutaneous musole of the face ; one of them, 

 after bending round the lower border of the inferior maxilla, reaches the 

 intermaxillary space. 



Functions of the Facial Nerve. — This nerve excites the contractility 

 of the muscles of the middle ear, external ear, the cheeks, lips, nostrils, 

 orbicularis of the eyelids, and the cervico-facial subcutaneous muscle. By 

 its great superficial petrous filament, it influences the movements of the 

 muscles of the soft palate, and it is admitted, as already noticed when speak- 

 ing of the gustatory nerve, that its tympano-lingual ramuscule acts as an 

 excitant to the submucous muscular layer of the tongue. The facial nerve, 

 also, without doubt, exercises its influence on the parotid gland ; thus its 

 action in this respect is not well determined ; perhaps it is limited to pro- 

 ducing the contractions of the excretory canaliculi which escape from the 

 lobes of the gland. 



It is to be remarked that the facial nerve has no influence over the 

 masseter muscle ; notwithstanding their intimate relations, it does not detach 

 the smallest filament to it. 



It is necessary to say, that its anastomoses with the various branches of 

 the trigeminus and pneumogastrio nerves, while endowing its distributive 

 ramuscules with great sensibility, in no respect modify its mode of action 



