Ulceration of the tongue is common and is usually due to dental trauma and aphthous ulcers. In the former there may be sharp teeth or poorly fitting dentures and the gums must be carefully checked for any associated damage. Falls, fits and sports or other injuries may be associated with tongue biting, and fish bones may lodge anywhere in the tongue or alimentary tract producing, trauma and infection.

Aphthous ulcers may be associated with generalised disease but are usually of unknown etiology. Ulcers may also be associated with inflammatory changes of the tongue and this glossitis may be due to generalised disease. Examples are drug reactions, such as Steven’s- Johnson and Magic syndromes. Sexually transmitted diseases causing glossitis and inflammation, include HIV, syphilis and gonorrhea, and may be part of Reiter’s syndrome. Autoimmune connective tissue disorders and occasionally gut abnormalities (such as ulcerative colitis and Crohn’s disease) have associated mouth ulceration. White patches are associated with candida but also with lichen planus, a disorder of unknown etiology. It has a number of characteristic patterns usually involving the edges of the tongue associated with mucosal atrophy and erosions. An important differential diagnosis of a white coating is leukoplakia, a premalignant condition (figure 6); note that this cannot be removed by scratching the mucosal surface.

Large tongues are seen in hypothyroidism and acromegaly, in developmental abnormalities and associated with some congenital disorders, such as Down’s syndrome.

The tongue receives bilateral cortical innervation, therefore wasting only occurs with bilateral upper motor neuron lesions (pseudobulbar palsy). However, the twelfth nerve nucleus may be affected by motor neuron disease and nerve damage from surgical or other trauma. With lower motor neuron paralysis the tongue deviates towards the side of the lesion (page 61). Tongue weakness and difficulty in swallowing may be present in myasthenia gravis and Parkinson’s disease. Thus disease can often be well demonstrated by asking the patient to stick their tongue out.

The features described in the examination of the tongue apply equally to the mucous membrane of the rest of the mouth and pharynx (figure 7a–c). Observe the inside of the upper and lower lip (figure 8a,b) and sulci passing on to the gums. Inspect the tonsillar bed and the oropharynx for erythema and nodularity. The tonsils and the lymphoid follicles on the back of the oropharynx are often prominent in young subjects and may become infected (figure 9). Note the mucosa over the hard and soft palate (figure 10), and the movement of the soft palate when asked to say ‘ah’.