Atrophy of the tongue is rare as a congenital condition. Hemi-atrophy occurs in various diseases of the central nervous system, as well as after injuries and diseases implicating the hypoglossal nerve.

Nervous Affections of the Tongue.—Neuralgia confined to the distribution of the lingual nerve is comparatively rare. It usually yields to medical treatment, but in inveterate cases it is sometimes necessary to resect the nerve.

It is more common to meet with a condition in which the patient complains of severe burning or aching pain in the region of the foliate papilla, which is situated on the edge of the tongue just in front of the anterior pillar of the fauces. The patient is usually a middle-aged, neurotic woman, and often with a gouty or rheumatic tendency. The pain, for which it is seldom possible to discover any cause, is usually worst at night, and may last for months, or even years. The practical importance of the condition is that, as the foliate papilla is prominent and red, it is liable to be mistaken on superficial examination for a commencing epithelioma. An inspection of the opposite side of the tongue, however, will reveal an exactly similar condition, which is not painful. The first and most important step in treatment is to assure the patient that the condition is not cancerous. Caustics and other irritating applications are to be avoided.

Spasm of the tongue sometimes occurs after injuries of the head implicating either the centre or the trunk of the hypoglossal nerve. It may also appear as a reflex condition in infective affections of the teeth and gums, or as a manifestation of some general disease of the central nervous system.

Paralysis of the tongue—unilateral or bilateral—may be due to injury or disease of the nerve centres of the hypoglossal nerve, more frequently to injury of or pressure on the nerve-trunk. The nerve may be bruised or divided in operations for the removal of tuberculous glands or other tumours in the neck. When the tongue is protruded it deviates towards the paralysed side, being pushed over by the active muscles of the opposite side ([Fig. 260]), and speech and mastication may be interfered with. The paralysed half of the tongue subsequently undergoes atrophy, but the functional disability largely disappears.

Fig. 260.—Temporary Unilateral Paralysis of Tongue, from bruising of hypoglossal nerve during operation for tuberculous cervical glands.

CHAPTER XXIII
THE SALIVARY GLANDS