FACIAL, OR NERVE OF EXPRESSION 509 



dilators and compressors of the nose, part of the buccinator, the levator 

 anguli oris and the zygomatic muscles. In its course it receives 

 branches of communication from the auriculo-temporal branch of the 

 inferior maxillary nerve. It joins also with the temporal branch of the 

 superior maxillary and with branches of the ophthalmic. It thus 

 becomes a mixed nerve and is distributed in part to integument. 



2. The cervico-facial nerve passes downward and forward to supply 

 the buccinator, orbicularis oris, risorius, levator labii inferioris, depressor 

 labii inferioris, depressor anguli oris and platysma. 



General Properties of the Facial Nerve. It has long been recog- 

 nized that the facial is the motor nerve of the superficial muscles of the 

 face and that its division produces paralysis of motion and no marked 

 effects on sensation. It is evident, also, from the communications 

 between the facial with the fifth, that it contains in its course sensory 

 fibres. Indeed, all who have operated on this nerve have found that it 

 is slightly sensory after it has emerged from the cranial cavity. It is 

 a question, however, of great importance to determine whether or not 

 the facial be endowed with sensibility by virtue of its own fibres of 

 origin. The main root evidently is from the motor tract, resembles the 

 anterior roots of the spinal nerves and is distributed to muscles ; but 

 this root is joined by the intermediary nerve of Wrisberg, which pre- 

 sents a small ganglionic enlargement that is analogous to the ganglia 

 on the posterior roots of the spinal nerves. The testimony of direct 

 experimentation is in favor of the insensibility of the facial at its origin. 

 It is true that the intermediary nerve of Wrisberg has a certain ana- 

 tomical resemblance to the sensory nerves, chiefly by reason of its 

 ganglioform enlargement ; but direct experiments are wanting, to show 

 that it is a nerve of general sensibility. 



Uses of the Branches of the Facial given off within the Aqueduct of 

 Fallopins. The first branch, the large petrosal, is the motor root of 

 Meckel's ganglion. This will be referred to again, in connection with 

 the sympathetic system. The second branch, the small petrosal, is one 

 of the motor roots of the otic ganglion. The third branch, the tym- 

 panic, is distributed exclusively to the stapedius muscle. The second 

 and third branches will be considered again, in connection with the 

 physiology of the internal ear. The fourth branch, the chorda tympani, 

 is so important that it demands special consideration. The fifth branch 

 is given off opposite the origin of the chorda tympani and passes to the 

 pneumogastric, to which nerve it probably supplies motor filaments. 

 In this branch, sensory filaments pass from the pneumogastric and 

 constitute a part of the sensory connections of the facial. 



Uses of the Chorda Tympani. This nerve passes between the 



