NERVES OF THE TYMPANUM. 



813 



nporal bone (fig. 296, cty), to reach the inner wall of the tym- supplies 

 num. In this cavity the nerve supplies filaments to the lining membrane, 

 ?mbrane, to the fenestra rotunda and fenestra ovalis, and to the 

 [<tacliian tube ; and it terminates in the three under-mentioned and other 

 inches, which are contained in grooves on the promontory, and Branches, 

 meet this nerve with others. 



Branches. 



One branch is arched forwards and downwards, and one to sy- 



pathetic, 



FIG. 300. JACOBSON'S NERVE IN THE TYMPANUM (BRESCHET). 



a. Carotid artery. 



b. Tensor tympani muscle. 



c. Inferior maxillary trunk of the 

 fifth nerve. 



d. Otic ganglion. 



Nerves : 



1. Petrosal ganglion of the glosso- 

 pharyngeal. 



2. Nerve of Jacobson. 



3. Sympathetic on the carotid. 



4. Small superficial petrosal nerve. 



5. Small deep petrosal nerve. 



6. Branch to Eustachian tube. 



7. Facial nerve. 



8. Chorda tympani. 



9. Nerve of the otic ganglion to 

 the tensor tympani muscle. 



enters the carotid canal to communicate with the sympathetic (*) 

 on the artery. 



The second ( 5 ) is the small deep petrosal nerve, which is directed small deep 

 forwards through a canal beneath the cochleariform process, to join 

 the carotid plexus of the sympathetic (sometimes also the large 

 superficial petrosal nerve) in the foramen lacerum. 



And the third (*) has the following course : It ascends in front and small 

 of the fenestra ovalis, and near the gangliform enlargement on the 

 facial nerve, to which it is connected by filaments. Beyond the 

 union with the facial, the nerve is named small superficial petrosal, 

 and is continued forwards through the substance of the temporal 



