6g2 TRIGEMINAL NERVE. 



of the submaxillary and sublingual glands, inasmuch as they contain se- 

 cretory nerves, yielding a limpid saliva, and vasodilators. In addition, 

 they give branches to the unstriated muscular fibers of Wharton's duct. 

 Not all of the fibers of the chorda, however, pass to the gland; some are 

 distributed to the tongue. 2. The sympathetic root of the ganglion 

 arises from the plexus of the submental branch of the external maxillary 

 artery (q), thus from the carotid plexus of the sympathetic. It passes 

 to the glands and is the secretory nerve yielding concentrated saliva. 

 It, further, transmits the vasoconstrictors to the vessels of the glands. 

 3. Sensory root -fibers derived from the lingual nerve in part send fila- 

 ments to the glands and their excretory ducts, and in part, again entering 

 the tympanicolingual from the ganglion, pass peripherally to the tongue. 



Pathological. Spasm of the muscles of mastication occurs as a pathological 

 manifestation in the distribution of the third division. It is, as a rule, bilateral, 

 and it may be either clonic (chattering of the teeth) or tonic (trismus). The 

 spasm is generally one of the manifestations of widespread convulsions; rarely it 

 is isolated as a symptom of cerebral focal disease of the medulla oblongata, the pons, 

 or the cortex in the situation of the motor center of the trigeminus. The spasm 

 may, naturally, be also reflex in origin, principally in consequence of irritation 

 of sensory nerves of the head. 



Degeneration of the motor nucleus or affections of the root in the skull cause 

 paralysis of the muscles of mastication, which is rarely bilateral. Paralysis of the 

 tensor tympani muscle is said to have caused impairment of hearing or roaring 

 in the ears. In this connection, as well as with respect to paralysis of the tensor 

 of the veil of the palate, further observations are desirable. 



With reference to all of the branches of the trigeminus, mention must be 

 made first of neuralgia, which is attended paroxysmally with intense radiating 

 pain in the peripheral distribution of the nerve. Generally unilateral, the dis- 

 order usually involves only a few branches or even fibers. Points of radiation 

 for the pain are often constituted by the bony canals from which the branches 

 make their exit. Rarely the ear, thie dura mater, and the tongue are involved. 

 Occasionally twitching occurs in the corresponding group of facial muscles in 

 conjunction with the attack, either being excited reflexly or developing directly 

 as a result of peripheral irritation of the facial fibers connected with the terminal 

 fibers of the trigeminus. The reflex contractions if marked may extend even to 

 the muscles of the arms and the trunk. 



Marked redness of the affected area occurs as an accompanying manifestation 

 of pain in the face, and in some cases increased or diminished secretion from the 

 conjunctiva and the nasal and buccal mucous membrane. The condition is cer- 

 tainly a reflex phenomenon of sympathetic origin. The derangement in cerebral 

 activity often observed in consequence of the altered distribution of blood is proba- 

 bly due to reflex vasomotor stimulation. C. Ludwig and Dittmar found that 

 irritation of sensory nerves causes contraction of the arterial blood-stream and 

 increased pressure in the cerebral vessels. Thus, melancholia and hypochondriasis 

 are often found in marked degree. Landois had cognizance of a case in which 

 during the severe attacks, involving the third division, marked visual hallucina- 

 tions appeared. Disorders of the fifth nerve are capable, in general, of causing 

 varied reflex affections. 



The trophic disorders that occur in association with affections of the trigeminus 

 are of great interest. Among these are brittleness and splitting of the hairs, 

 graying and falling out of the hair, circumscribed inflammation of the skin and 

 vesicular eruptions on the face (zoster) and also the cornea (neuralgic herpes of 

 the cornea). 



Finally, there should be mentioned progressive facial atrophy, which is almost 

 always unilateral, but may also be bilateral. It is probably due to derangement 

 in the trophic activity (of the descending root?) of the trigeminus, although the 

 vasomotor activity of the sympathetic may also be invoked reflexly. Landois 

 found on sphygmographic examination of the famous case of Romberg (in a man 

 named Schwahn) that the pulse-tracing from the carotid on the atrophic side was 

 distinctly smaller than that from the vessel on the unaffected side. Intracranial 

 division of the sensory root of the fifth nerve causes in dogs a similar trophic dis- 

 turbance. The antithesis of this obscure disorder, which is dependent upon the 



