These form a pair of ‘curtains’ before the mouth, each composed of a layer of skin and of mucous membrane, between which lies a considerable amount of fat and of muscle ﬁbres.
Fissures coming on in cold weather are often diﬃcult to get rid of. Peeling and cracking of the vermilion of the lips is common in those exposed for long periods to wind and sunlight. Treatment consists of the application of aqueous cream. If the main cause is excessive exposure to sunlight – in which case the lower lip is mainly aﬀected – a protective cream should be applied.
Herpes in the form of ‘cold sores’ often develops on the lip as a result of a cold or other feverish condition, but quickly passes oﬀ (see HERPES SIMPLEX).
Ulcers may form on the inner surface of the lip, usually in consequence of bad teeth or of DYSPEPSIA.
Small cysts sometimes form on the inner surface of the lip, and are seen as little bluish swellings ﬁlled with mucus; they are of no importance.
Hare-lip is a deformity sometimes present at birth (see PALATE, MALFORMATIONS OF).
Cancer of the lip sometimes occurs – almost always in men, and usually on the lower lip. (See also MOUTH, DISEASES OF.)