What is the anatomy of the lips relative to complex lip laceration?

Updated: Aug 25, 2020
  • Author: Gretchen S Lent, MD; Chief Editor: Erik D Schraga, MD  more...
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The lips are composed of 3 major layers: skin, muscle, and oral mucosa.

The philtrum is the vertical groove located directly adjacent to and above the upper lip and below the nose.

The commissures are the lateral borders of the oral cavity where the upper and lower lips join.

The vermilion is the white roll that forms the border between the lip and surrounding skin (see the image below). This area is the focus of repair because even 1 mm of vermilion misalignment may be noticeable.

Illustration of the upper and lower vermilion bord Illustration of the upper and lower vermilion border.

Nerve supply

The upper lip and the skin between the upper lip and lower eyelid are innervated by the infraorbital nerve on either side.

The lower lip, gums, and skin between the lower lip and chin are innervated by the mental nerve.

For a detailed discussion of lip anatomy, see the Medscape article Lips and Perioral Region Anatomy.

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