Navel

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For other uses, see Navel (disambiguation).
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Navel
Ombelico.JPG
human navel
Latin Umbilicus

The navel (clinically known as the umbilicus, colloquially known as the belly button, umbilical dip or tummy button) is a scar[1] on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel, and it is quite conspicuous in humans.[2] Other animals' navels tend to be smoother and flatter, often nothing more than a thin line, and are often obscured by fur.[3]

Human anatomy[edit]

The navel is the centre of the circle in this drawing of the Vitruvian Man by Leonardo da Vinci

The umbilicus is a prominent mark on the abdomen, with its position being relatively consistent amongst humans. The skin around the waist at the level of the umbilicus is supplied by the tenth thoracic spinal nerve (T10 dermatome). The umbilicus itself typically lies at a vertical level corresponding to the junction between the L3 and L4 vertebrae,[4] with a normal variation among people between the L3 and L5 vertebrae.[5] The umbilicus forms a visible depression on the skin of the abdomen, and the underlying abdominal muscle layers also present a concavity; thinness at this point contributes to a relative structural weakness, making it susceptible to hernia.[citation needed] During pregnancy, the uterus presses the navel of the pregnant woman outward; it usually retracts again after birth.

The umbilicus is used to visually separate the abdomen into quadrants. The navel is the center of the circle enclosing the spread-eagle figure in Leonardo da Vinci's Vitruvian Man drawing. The navel is rarely the focus in contemporary art and literature.[6]

Aki Sinkkonen at the University of Helsinki in Finland thinks that the navel may be an indicator of mating potential in fertile women. In his article in the The FASEB Journal, he proposes that the umbilicus, together with the surrounding skin area, is an honest signal of individual vigor. He suggests that the symmetry, shape, and position of umbilicus can be used to estimate the reproductive potential of fertile females, including risks of certain genetically and maternally inherited fetal anomalies.[7][8]

Innies and outies[edit]

An "outie" navel on a female

In humans, the navel scar can appear as a depression (often referred to colloquially as an "innie") or as a protrusion ("outie"). About 90% of humans have innies.[3] The occurrence of an "outie" navel is caused by the extra scar tissue left from the umbilical cord[9] or from umbilical hernias, although the latter does not always cause an "outie" to develop. Frequently separated into just those two categories, navels vary quite widely among people in terms of size, shape, depth, length, and overall appearance. As navels are scars, and not defined by genetics, they can serve as a way of distinguishing between identical twins in the absence of other identifiable marks.

Disorders[edit]

The navel can be involved in umbilical sinus or fistula, which in rare cases can lead to menstrual or fecal discharge from the navel. Menstrual discharge from the umbilicus is associated with umbilical endometriosis, a rare disorder.[10][11]

Loss of the navel[edit]

Some people do not have a navel as a result of surgery needed to correct abdominal problems at birth such as umbilical hernia or gastroschisis, a condition where the stomach and intestines poke through a hole in the abdominal wall. Only a smooth indentation is found in the place of the navel.[12] Adults may lose their navels during abdominal surgeries or skin grafts, while some adults opt to have their navels surgically enhanced via umbilicoplasty.

Erogenous zone[edit]

A T-shaped navel

The navel is one of the many erogenous zones that has heightened sensitivity.[13] The navel and the region below when touched by the finger or the tip of the tongue result in the production of erotic sensations.[13][14] This is because the navel and the genitals have a common tissue origin, and in some people this connection still exists[dubious ] so that stimulation of the navel will elicit a distinct tickle in the genitals.[15] A study done by Charles Puckett of the University of Missouri found that vertically oriented navels with a T-shape were considered the most attractive.[2][16][17][18]

Bacteria[edit]

A team of scientists have discovered 1,400 strains of bacteria in human umbilical dips.[19] North Carolina State University's Belly Button Biodiversity study found 662 unrecognised strains that could be unique new species.[19][20][21]

Navel in human culture[edit]

There are many conceptions, customs, fashion and taboos associated with the human navel in the human social context. These have varied in ideas and trends across regions and throughout history. Social mores about the navel in clothing and human social traditions has been given diverse narratives and significance across human social world.


See also[edit]

References[edit]

  1. ^ Ins and outs of a beautiful belly button; As Katie Holmes shocks navel-gazers. Goliath.ecnext.com (30 June 2011).
  2. ^ a b Important Facts About Navel. Memorylogix.com (23 April 2011).
  3. ^ a b The Ins and Outs of Belly Buttons. Divinecaroline.com (27 May 2009).
  4. ^ Ellis, Harold (2006). Clinical Anatomy: Applied Anatomy for Students and Junior Doctors. New York: Wiley. ISBN 1-4051-3804-1. [1]
  5. ^ Basic Human Anatomy – O'Rahilly, Müller, Carpenter & Swenson – Chapter 25: Abdominal walls. Dartmouth Medical School. Retrieved November 2010
  6. ^ REGINA HACKETT (30 May 2002). "Dunning's examination of torsos is a truly navel experience". Seattle Post-Intelligencer. Retrieved 19 March 2012. 
  7. ^ Belly Buttons May Signal a Woman's Vigor. Livescience.com (3 February 2009).
  8. ^ Umbilicus as a fitness signal in humans – Aki Sinkkonen. Fasebj.org (1 January 2009).
  9. ^ http://www.divinecaroline.com/self/self-discovery/ins-and-outs-belly-buttons
  10. ^ Bagade, Pallavi V; Guirguis, Mamdouh M (2009). "Menstruating from the umbilicus as a rare case of primary umbilical endometriosis: a case report". Journal of Medical Case Reports 3 (1): 9326. doi:10.1186/1752-1947-3-9326. ISSN 1752-1947. 
  11. ^ http://pediatriceducation.org/2008/06/02/, retrieved 2014-06-02  Missing or empty |title= (help)
  12. ^ Bingham, John. (18 November 2008) 'No belly button' model Karolina Kurkova sets fashion world navel gazing. The Daily Telegraph.
  13. ^ a b A celebration of sex – Douglas E. Rosenau – Chapter 3 – Your Erogenous Zones.
  14. ^ Touch Me There!: A Hands-On Guide to Your Orgasmic Hot Spots – Yvonne K. Fulbright.
  15. ^ The Essence of Tantric Sexuality – Sex and Sexuality Series – Mark A. Michaels, Patricia Johnson, Rudolph Ballentine – Chapter 13 – Tertiary Erogenic Zones. Google Books.
  16. ^ "Your 'belly button' can attract love!". The Times of India. 4 February 2009. Retrieved 16 March 2012. 
  17. ^ The Ins and Outs of Belly Buttons. Divinecaroline.com (27 May 2009).
  18. ^ Attractive umbilicus (belly button) in women. Femininebeauty.info.
  19. ^ a b Gayle, Damien (8 July 2011). "Navel-gazing scientists discover the human belly button harbours 1,400 strains of bacteria". Daily Mail (London). Retrieved 10 January 2012. 
  20. ^ Aldhous, Peter (4 July 2011). "Scientists find a rich array of unknown bacteria in human navels". The Washington Post. Retrieved 10 January 2012. 
  21. ^ "Human Belly Button Is Home to Hundreds of Never-Before-Seen Species". POPSCI. Retrieved 10 January 2012.