Lower lip

Labium inferius oris

Integumentary (skin)SkinHead

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What it is
The lower lip vermilion, fuller than the upper lip, resting on the lower incisors. The red colour comes from blood in capillaries seen through a thin, non-keratinised, hair-less epithelium.
Function
Closes the mouth, seals around food and drink, shapes speech sounds and is one of the most touch-sensitive areas of the body.
Size
Vermilion ~5 cm wide, ~10 mm high
Clinical note
The lips lack sweat and sebaceous glands and so dry and crack easily; the vermilion border must be realigned exactly when repairing a cut lip or cleft lip.