Lip

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Lip
Female lips
Latin	labia oris
Artery	inferior labial, superior labial
Vein	inferior labial, superior labial
Nerve	frontal, infraorbital

Lips are a visible lip part at of humans and many animals. Lips are soft, movable, and serve as the opening for , as an erogenous organ used in kissing and other acts of intimacy, as a tactile sensory organ, and in the articulation of speech.

Contents 1 Anatomical basics of the human lip 2 Anatomy in detail 2.1 Sensory nerve supply 2.2 Blood supply 3 Symbolic meaning 4 Changes to the lip 5 Diseases 6 Literature 7 References 8 See also 9 Additional images 10 External links

[edit] Anatomical basics of the human lip

One differentiates between the Upper (Labia superfluos entafada) and lower lip (Labium inferius). The lower lip is usually somewhat larger. The border between the lips and the surrounding skin is referred to as the vermillion border, or simply the vermilion. The vertical groove on the upper lip, is known as the philtrum.

The skin of the lip, with three to five cellular layers, is very thin compared to typical face skin, which has up to 16 layers. With light skin color, the lip skin contains fewer melanocytes (cells which produce melanin pigment , which give skin its color). Because of this, the blood vessels appear through the skin of the lips, which leads to their notable red coloring. With darker skin color this effect is less prominent, as in this case the skin of the lips contains more melanin and thus is visually thicker. The skin of the lip forms the border between the exterior skin of the face, and the interior mucous membrane of the inside of the mouth.

The lip skin is not hairy, and does not have sweat glands or sebaceous glands. Therefore it does not have the usual protection layer of sweat and body oils which keep the skin smooth, inhibit pathogens, and regulate warmth. For these reasons, the lips dry out faster and become chapped more easily.

[edit] Anatomy in detail

The skin of the lips is stratified squamous epithelium. The mucous membrane is represented by a large area in the sensory cortex, and is therefore highly sensitive. The Frenulum Labii Inferioris is the frenulum of the lower lip. The Frenulum Labii Superioris is the frenulum of the upper lip.

[edit] Sensory nerve supply

• Trigeminal nerve
  • The infraorbital nerve is a branch of the maxillary branch. It supplies not only the upper lip, but much of the skin of the face between the upper lip and the lower eyelid, except for the bridge of the nose.
  • The mental nerve is a branch of the mandibular branch ( via the inferior alveolar nerve). It supplies the skin and mucous membrane of the lower lip and labial gingiva (gum) anteriorly.

[edit] Blood supply

The facial artery is one of the six non-terminal branches of the external carotid artery. It supplies the lips by its superior and inferior labial branches, each of which bifurcate and anastomose with their companion artery from the other side.

[edit] Symbolic meaning

Lips are often viewed as a symbol for sensuality and sexuality. This has many origins; above all, the lips are a very sensitive erogenous and tactile organ. Furthermore, in many cultures of the world, a woman's mouth and lips are veiled because of their representative association with the vulva, and because of their role as a woman's secondary sexual organ ^[1].

As part of the mouth, the lips are also associated with the symbolism associated with the mouth as orifice by which food is taken in. The lips are also linked symbolically to neonatal psychology (see for example oral stage of the psychology according to Sigmund Freud).

[edit] Changes to the lip

• One of the most frequent changes of the lips is a blue coloring due to cyanosis; the blood contains less oxygen, and thus has a dark red to blue color, which shows through the thin skin. Cyanosis is the reason why corpses always have blue lips. In cold weather cyanosis can appear, so especially in the winter, blue lips may not be an uncommon sight.
• Lips can (temporarily) swell. The reasons for this are varied and can be from sexual stimulation, injuries and side effects of medications, or misalignment of teeth.
• Cracks or splits in the angles of the lips could be the result of an inflammation of the lips, Angular cheilitis.

[edit] Diseases

As an organ of the body, the lip can be a focus of disease or show symptoms of a disease:

• Lip herpes (technically Herpes labialis, a form of herpes simplex) is a viral infection which appears in the formation of painful blisters at the lip. It's also commonly known as a cold sore.
• Carcinoma (a malignant cancer that arises from epithelial cells) at the lips, is caused predominantly by using tobacco and overexposure of sunlight. To a lesser extent, it could also come from lack of oral hygiene or poor fitting dentures. Alcohol appears to increase the carcinoma risk associated with tobacco use.

[edit] Literature

Scientific Sources:

• Tomiyama N, Ichida T, Yamaguchi K (2004). "Electromyographic activity of lower lip muscles when chewing with the lips in contact and apart" (abstract). Angle Orthod 74 (1): 31–6. PMID 15038488. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-3219&volume=74&page=31. 

• Bisson M, Grobbelaar A (2004). "The esthetic properties of lips: a comparison of models and nonmodels" (abstract). Angle Orthod 74 (2): 162–6. PMID 15132441. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-3219&volume=74&page=162. 

• McMinn, R. M. H.; Last, R. J. (1994). Last's anatomy, regional and applied. Edinburgh: Churchill Livingstone. ISBN 0-443-04662-X. 

[edit] References

[edit] See also

Look up lip in Wiktionary, the free dictionary.

• Kiss
• Lipstick
• Lip gloss
• Lip balm
• Lip piercing
• Facial expression
• Herpes
• Chapped lips
• Cupid's bow
• Cleft lip
• Lip enhancement

[edit] Additional images

The labial coronary arteries, etc.

[edit] External links

Wikimedia Commons has media related to: Lips

• ent/7 at eMedicine
• hednk-030 — Embryology at UNC
• Anatomy at oralhealth.dent.umich.edu

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