FIFTH CEANIAL NEEVE. 197 



occur when there is disease of the temporo-mandibular articula- 

 tion, which is supplied by the auriculo- temporal branch of the 

 fifth nerve. 



The sensory symptoms referable to the nerve may, like the 

 motor, be either irritative or paralytic. The cause of epilepti- 

 form neuralgia, such as is treated successfully by excision of the 

 Gasserian ganglion with its attached sensory root is obscure. 

 Similar intense neuralgia may be produced by the irritation 

 of a tumour of the meninges, for the fifth nerve distributes 

 recurrent filaments to them. If its trunk is implicated by 

 the tumour, anaesthesia as well as neuralgia may be expected. 

 When terminal filaments of the nerve are exposed to irritation 

 the pain is often referred to other parts to which the nerve 

 is distributed. Malignant disease of the tongue is well known 

 as a cause of pain referred to the ear, which pain may be 

 accompanied by salivation, also brought about through the 

 agency of the fifth nerve. During eruption of the temporary 

 molars, children may be observed to pull and rub their ears, 

 and otitis may be suspected. Pain in a decayed tooth is often 

 referred to the corresponding tooth in the jaw of the same 

 side. Decayed teeth may also give rise to frontal, infraorbital, 

 mental, or auricular pain. Frontal headache may accompany 

 disease of the nose or its accessory air sinuses. As already 

 indicated, the grey matter of the sensory nucleus is continuous 

 with that from which the cervical nerves spring, and this may 

 account for the radiation of pain from the territory of the fifth 

 to that of adjacent cervical nerves. 



Herpes often occurs in the area of distribution of the fifth 

 nerve. When the nasal branch is involved, as is shown by the 

 appearance of the eruption near the tip of the nose, ulceration 

 of the cornea, iritis or even cyclitis may supervene. This 

 association is explained by the fact that nerves for the front parts 

 of the eye are derived from the nasal nerve during its course 

 through the orbit, reaching the eye through the lenticular 

 ganglion. 



The rapid destruction of the eye which sometimes occurs in 



