THE FACIAL NERVE. 



1253 



glosso-pharyngeal to form the small superficial petrosal and proceeds to the otic 

 ganglion, which it enters as the sensory root (page 1246). The fibres from the tym- 

 panic plexus, probably secretory in function, are distributed from the otic ganglion to 

 the parotid gland. 



3. The external superficial petrosal nerve is very small and is not always 

 present. It joins the sympathetic plexus on the middle meningeal artery. 



4. The stapedial nerve (n. stapedius), for the supply of the stapedius muscle, 

 is given off as the facial passes downward behind the pyramid in the posterior wall of 

 the tympanic cavity, the nerve gaining access to the muscle by passing through a 

 minute orifice in the base of the pyramid. 



FIG. 1068. 



Sup 



Temporal branch of 



temporo-malar ifcLj] 

 Mastoid branch of 



great auricular 



Auriculo-temporal 



Malar branch of facial 



Temporal branch 



of facial 



Infraorbital branch 

 of facial 



Facial nerve 



Great occipital nerve 



Buccal branch of facial 

 Supramanclibular branch of facial 

 Inframandibular branch of facial 



Small occipital nerve 



Cutaneous branch of III. cervical 



Great auricular nerve 



iraorbital nerve 

 atrochlear nerve 



ratrochlear nerve 

 Malar branch of 



temporo- malar 

 Infraorbital nerve 

 External branch of 

 nasal nerve 



Superficial cervical nerve 



Superficial Dissection of head and neck, showing terminal branches of trigeminal, facial and great occipital nerves, 

 as well as associated branches of cervical plexus. 



5. The chorda tympani nerve (n. chorda tympani), while conveying both 

 motor and sensory impulses, consists mainly of sensory fibres derived from the cells 

 of the geniculate ganglion. It arises from the facial a short distance above the stylo- 

 mastoid foramen and courses upward and forward through the iter chordae posterius 

 to enter the tympanic cavity (Fig. 1067). Passing between the fibrous and mucous 

 layers of the membrana tympani, over the tendon of the tensor tympani and between 

 the long processes of the incus and malleus, it arrives at the anterior edge of the 

 membrane. It then traverses the iter chordae anterius to reach the pterygo-maxillary 

 region, and, after receiving a filament from the otic ganglion, takes a course down- 

 ward and forward, after which, under cover of the external pterygoid muscle, it unites 

 and becomes incorporated with the lingual branch of the mandibular nerve. As the 

 latter passes above the submaxillary ganglion, the motor fibres of the chorda 

 tympani (facial) descend to the ganglion as its motor root and probably eventually 

 end as secretory fibres to the submaxillary and sublingual glands. The sensory 



