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Lip: anatomy, location and function

The lips are two muscular, mobile folds that surround the opening of the mouth. They close the mouth, help in speech, eating and facial expression, and contain tactile receptors.

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Skin0%
Muscles100%

Structures

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Highlighted in the model: Lip. Click any part to read about it, or switch off “Highlight topic” to see the whole body. 3D data: BodyParts3D, © The Database Center for Life Science, CC BY 4.0; meshes simplified and recoloured. The model is an adult male.

Lip at a glance

What it is
The lips are two muscular, mobile folds that surround the opening of the mouth.
Location
They form the anterior boundary of the oral cavity, with the orbicularis oris muscle at their core.
Function
They close the mouth, help in speech, eating and facial expression, and contain tactile receptors.
Body system
Digestive · single, midline structure
FMA ID
FMA59816 (Foundational Model of Anatomy)

Key facts

  • Covered externally by skin and internally by oral mucosa, with the red vermilion between them.
  • Motor supply is from the facial nerve. Sensation comes from the infraorbital nerve (upper lip) and mental nerve (lower lip), both trigeminal branches.

Clinical relevance

Cleft lip results from failed fusion of the maxillary prominence with the merged medial nasal prominences.

Structures next to the lip

The nearest named structures in the 3D model, measured from the centre of each part:

References

  1. Foundational Model of Anatomy: Lip (FMA59816). EMBL-EBI Ontology Lookup Service.
  2. OpenStax. Anatomy and Physiology 2e, §23.1 Overview of the Digestive System. Rice University, 2022.
  3. Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.

Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.