The Motor Nerves of the Eyeball.
Third, Fourth, and Sixth.
Diseases belonging to the motor nerves (motor oculi, patheticus, and abducens), properly belong to ophthalmology, and need not be considered here.
The Fifth Nerve (Trifacial).
The fifth nerve is a compound nerve, being the great sensory nerve of the head and face, and the motor nerve of the muscles of mastication.
The ophthalmic and superior maxillary divisions are entirely sensory; the inferior maxillary, the third division, is partly sensory and partly motor.
The ophthalmic division supplies the eyeball, the lachrymal gland, the mucous lining of the eye and nasal fosse, and the integument of the eyebrow, forehead, and the nose.
The superior maxillary division supplies the infraorbital region, the skin over the malar bone, the root of the nose, the upper lip, a large part of the nasal mucous membrane, the palate, the upper part of the pharynx, the teeth in the upper jaw, and the integument covering the temple and side of the forehead.
The inferior maxillary division supplies the teeth and gums of the lower jaw, the integument of the temple and external ear, the lower part of the face, and the lower lip, the tongue, and the muscles of mastication.
Lesions of the fifth nerve may be due to pontine hemorrhage or tumors of the pons, to softening or sclerosis; meningitis; injury at the base of the brain; gummata; caries of bone; or it may be due to injuries or disease of the branches after passing out, as a neuritis, or from pressure by growths.
Symptoms.—Sensory Portion.—In the early stage, pains of a shooting, boring, or burning character are observed, with tenderness along the course of the nerve, and certain areas where there is hyperesthesia; this is followed later by anesthesia of the skin of the face and head, the conjunctiva, the mucosa of the tongue, lips, nose, and of the soft and hard palate. The muscles of the face become slower in their action, the senses of smell and taste are impaired, and the salivary, lachrymal, and buccal secretions are diminished.
Motor Portion: Paralysis.—The temporal and massiter muscles. may be partially or entirely paralyzed, the jaw being drawn to the affected side.
Spasm of the masticatory muscles—spasm of Romberg—may be tonic or clonic. In the tonic spasms the jaws are firmly locked (locked jaw), rigid, and frequently painful.
Clonic spasms may occur as a symptom of chorea, hysteria, and sometimes in women, late in life.
Treatment.—This will depend upon the conditions present. For the sensory wrongs, when not due to organic lesions, much relief may be secured from specific plantago major, gelsemium, melilotus, and piper methysticum. Where the pain is intense, morphia may have to be used. When due to specific causes, the iodids and similar remedies will be required.
Galvanism and Faradism will be useful in some cases.