Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. The upper and lower lips are referred to as the Labium superius oris and Labium inferius oris, respectively; they are formed by the outer surface of the anterior two-thirds of the tubercle of the lower jaw and by the orbicularis oris muscle. The junction between the skin of the lip and the skin of the face is called vermilion border (or cupid's bow), which is caused by a slight elevation at this juncture. The vermilion border has a slightly different color from that of surrounding skin (usually redder), due to differences in vascular supply, thickness, keratinization, melanin pigment content, and surface tension. The vermilion surface of the lip is covered with squamous epithelium (skin). It contains many blood vessels that cause it to look red, but it is not a mucous membrane; rather it is keratinized stratified squamous epithelium. The epidermis (top layer) appears smooth from a distance but is actually composed of minute conical papillae that give it a velvety feel. In addition,

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