Lip
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The lips are a horizontal pair of
Structure
The upper and lower lips are referred to as the labium superius oris and labium inferius oris, respectively.
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
The lip skin is not hairy and does not have
The lower lip is formed from the
The upper lip covers the
It is raised by the
Thinning of the vermilion of the upper lip and flattening of the
Microanatomy
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.
Nerve supply
- Trigeminal nerve
- The infraorbital nerve is a branch of the maxillary branch. It supplies not only the upper lip but also much of the skin of the face between the upper lip and the lower eyelid, except for the bridge of the nose.
- The gingiva(gum) anteriorly.
Blood supply
The facial artery is one of the six non-terminal branches of the external carotid artery.
This artery supplies both lips by its superior and inferior labial branches. Each of the two branches bifurcate and anastomose with their companion branch from the other terminal.
Muscles
The muscles acting on the lips are considered part of the muscles of
The muscles acting on the lips:
- Buccinator
- Orbicularis oris (a complex of muscles, formerly thought to be a single sphincter or ring of muscle)
- Anchor point for several muscles
- Modiolus
- Lip elevation
- Lip depression
Functions
Food intake
Because they have their own muscles and bordering muscles, the lips are easily movable. Lips are used for eating functions, like holding food or to get it in the mouth. In addition, lips serve to close the mouth airtight shut, to hold food and drink inside, and to keep out unwanted objects. Through making a narrow
Articulation
The lips serve for creating different sounds—mainly labial, bilabial, and labiodental consonant sounds as well as vowel rounding—and thus are an important part of the speech apparatus. The lips enable whistling and the performing of wind instruments such as the trumpet, clarinet, flute, and saxophone. People who have hearing loss may unconsciously or consciously lip read to understand speech without needing to perceive the actual sounds, and visual cues from the lips affect the perception of what sounds have been heard, for example the McGurk effect.
Tactile organ
The lip has many
Erogenous zone
Because of their high number of nerve endings, the lips are an
A woman's lips are also a visible expression of her fertility. In studies performed on the science of human attraction, psychologists have concluded that a woman's facial and sexual attractiveness is closely linked to the makeup of her hormones during puberty and development. Contrary to the effects of
Lip size is linked to sexual attraction in both men and women. Women are attracted to men with masculine lips that are more middle size and not too big or too small; they are to be rugged and sensual. In general, the researchers found that a small nose, big eyes and voluptuous lips are sexually attractive both in men and women.[11] The lips may temporarily swell during sexual arousal due to engorgement with blood.[medical citation needed]
Facial expression
The lips contribute substantially to facial expressions. The lips visibly express emotions such as a smile or frown, iconically by the curve of the lips forming an up-open or down-open parabola, respectively. Lips can also be made pouty when whining or perky to be provocative.
Clinical significance
As an organ of the body, the lip can be a focus of disease or show symptoms of a disease:
- 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 sometimes have blue lips. In cold weather cyanosis can appear, so especially in the winter, blue lips may not be an uncommon sight.[12]
- Inflammation of the lips is termed herpes simplex) and actinic cheilitis (chronically sun damaged lips).[13]
- Cleft lip is a type of birth defect that can be successfully treated with surgery.[14]
- basocellular carcinoma.[17]
Society and culture
Lips are often viewed as a symbol of 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.[18]
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).
Lip piercing or lip augmentation is sometimes carried out for cosmetic reasons. Products designed for use on the lips include lipstick, lip gloss and lip balm.
Other animals
In most vertebrates, the lips are relatively unimportant folds of tissue lying just outside the jaws. However, in
See also
References
- ^ "Definition of LIP". Merriam-Webster. Retrieved 2022-05-22.
- ^ "Labium Superius Oris -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Labium Inferius Oris -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Vermilion Border -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Vermilion Zone -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Cupid's Bow -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Tubercle Of Upper Lip -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- ^ "Philtrum -- Medical Definition". medilexicon.com. Archived from the original on 2014-10-17. Retrieved 2011-11-12.
- S2CID 23542024.
- ^ Note, Science (2005-11-28). "Why do men find big lips and little noses so sexy? I'll paint you a picture – Comment – Times Online". The Times. London. Archived from the original on February 22, 2007. Retrieved 2007-12-12.
- ^ "Lip size key to sexual attraction". BBC News. 2003-03-04. Retrieved 2010-01-15.
- PMID 29489181, retrieved 2021-07-08
- PMID 29262127, retrieved 2021-07-08
- ^ CDC (2020-12-28). "Facts about Cleft Lip and Cleft Palate | CDC". Centers for Disease Control and Prevention. Retrieved 2021-07-08.
- ^ "Lip cancer - Symptoms and causes". Mayo Clinic. Retrieved 2021-07-08.
- ^ "Risk Factors for Oral Cavity and Oropharyngeal Cancers". www.cancer.org. Retrieved 2021-07-08.
- PMID 21808457.
- ^ Valsiner, Jaan (2000). Culture and Human Development. Sage Publications, Ltd. pp. 134–136.
- S2CID 42179436. Retrieved 9 November 2020.
- ISBN 978-0-03-910284-5.
- Karger. 9–15.
Further reading
- Tomiyama N, Ichida T, Yamaguchi K (2004). "Electromyographic activity of lower lip muscles when chewing with the lips in contact and apart". Angle Orthod (Abstract). 74 (1): 31–6. PMID 15038488.
- Bisson M, Grobbelaar A (2004). "The esthetic properties of lips: a comparison of models and nonmodels". Angle Orthod (Abstract). 74 (2): 162–6. PMID 15132441.
- McMinn, R. M. H.; Last, R. J. (1994). Last's anatomy, regional and applied. Edinburgh: ISBN 978-0-443-04662-9.
External links
- ent/7 at eMedicine
- hednk-030—Embryo Images at University of North Carolina
- Anatomy at oralhealth.dent.umich.edu
- Media related to Lips at Wikimedia Commons
- Quotations related to Lips at Wikiquote