328 DISEASES OF THE PERIPHERAL NERVES. 



traction of the foramina through which the nerves pass, or even inflam- 

 mation and projections on the bones. Finally, in some cases, aneurisms, 

 tumors, thickening of the dura mater, exostoses within the skull, which 

 pressed on the trigeminus, have been found as evident cause for ob- 

 stinate and extensive neuralgia of the branches of that nerve. I do 

 not know a single case that shows an unequivocally central origin of 

 facial neuralgia. Among the cases described by Romberg, in one 

 case of neuralgia of the trigeminus that had lasted for twenty-six 

 years, it is true there was a small diseased spot in the pons, but there 

 was at the same time an aneurism of the carotid compressing the tri- 

 geminus, which would fully have accounted for the neuralgia. 



Far more frequently no material causes can be found for facial neu- 

 ralgia. In such cases it is very probable, but cannot be proved, that 

 the disease is occasionally caused by catching cold, which induces hy- 

 peraemia and slight oedema of the neurilemma that disappear after 

 death. Cases of haemorrhoidal facial neuralgia and those from sup- 

 pression of perspiration and exanthemata are very problematical; 

 arthritic cases are somewhat less so. Neuralgia of the trifacial is the 

 most frequent form when the disease is due to malaria. 



The rather worthless results of statistics show that facial neural- 

 gia is rare in childhood, most frequent between the thirtieth and 

 fiftieth years, and somewhat more common in women than in men. 



SYMPTOMS AND COURSE. Of course, the pain from which patients 

 with neuralgia of the trigeminus suffer is more extensive in proportion 

 as the branch of the nerve affected is larger ; and conversely, from the 

 limitation of the pain to a circumscribed spot, we may decide that a very 

 email branch is the seat of the disease. Moreover, as the filaments of 

 a nerve are the more numerous the nearer we go to its origin in the brain, 

 and become fewer as it approaches the surface, it follows that, when 

 the pain is very limited, we may consider its origin as peripheral ; where 

 it is very extensive, we may decide that the injurious influence is in the 

 skull itself. In fact, in neuralgias caused by pressure on the trunk of 

 the fifth pair, pain has been observed hi all parts supplied by its sen- 

 sory filaments, in the anterior surface of the ear, in the skin of the 

 forehead, temple, face, in the orbit, nose, palate, body of the tongue, 

 floor of the mouth, teeth, and probably in the dura mater. Vattefa 

 mentions numerous points douloureux in facial neuralgia; we shall 

 only call attention to three of them, which lie nearly in a vertical 

 straight line, and correspond to the supraorbital foramen, the anterioi 

 opening of the suborbital canal, and the mental foramen. If the neu- 

 ralgia be seated in the first branch of the trigeminus, the pain spreads 

 particularly in the branches of the supraorbital, and affects the forehead, 

 eyebrows, and upper eyelid. In some rare cases the pain is chiefl\ T ir 



