A rare disorder in which the FRENUM connecting the lower surface of the tongue to the floor of the mouth is so short or tight that the tongue cannot be protruded. Surgery can remedy the defect. It is easy to overdiagnose and is not a common cause of difficulty in feeding at birth or speech defects in infancy.

This is gross enlargement of the tongue, which may protrude from the mouth. It can make speech indistinct and make swallowing and even breathing difficult. The cause may be CONGENITAL, as in severe cases of DOWN'S SYNDROME, or it may occur as a result of ACROMEGALY or be due to abnormal deposits as in AMYLOIDOSIS.

After a STROKE involving the motor nerve centre, the control of one side of the tongue musculature may be lost. This will result in the protruded tongue pointing to the side of the body which is paralysed. The sense of taste on one side of the tongue may also be lost in some diseases of the brain and facial nerve.

This is due to thickening of the superficial layers of the tongue, which may appear like hairs which trap food debris and become discoloured. Furring is common during fever and as a result of mouth-breathing and smoking.

(Left) Tongue from above showing different areas of taste discrimination. (Right) Vertical section through surface of tongue showing taste-bud (x 400).

In some conditions the tongue may appear dry, red and raw (GLOSSITIS). An inflamed beefy tongue is characteristic of pellagra, a disease caused by deficiency of NICOTINIC ACID in the diet. A magenta-coloured tongue may be seen when there is a lack of RIBOFLAVIN.

These are similar to those elsewhere in the mouth. The most common is an aphthous ulcer, which is small, red and painful, may be multiple and lasts for about ten days. These are associated with stress, mild trauma (such as from jagged teeth), and occasionally with folic acid and vitamin B12 deficiency. Ulcers of the tongue are sometimes found in patients with chronic bowel disease.