Navel

The navel (clinically known as the umbilicus, colloquially known as the belly button, 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]

Structure

An "outie" navel

An "innie" navel

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

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.^[4]

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,^[5] with a normal variation among people between the L3 and L5 vertebrae.^[6]

While the shape of the human navel may be affected by long term changes to diet and exercise, unexpected change in shape may be the result of ascites.^[7]

Clinical significance

Disorders

In addition to change in shape being a possible side effect from ascites and umbilical hernias, 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.^[8][9]

Surgery

To minimize scarring, the navel is a recommended site of incision for various surgeries, including transgastric appendicectomy,^[10] gall bladder surgery,^[11] and the umbilicoplasty^[12] procedure itself.

Society and culture

The public exposure of the male and female midriff and bare navel has been taboo at times in Western cultures, being considered immodest or indecent. It was banned in some jurisdictions, however the community perceptions have changed and exposure of female midriff and navel is more accepted today and in some societies or contexts, it is both fashionable and common, though not without its critics.^[13]

While the West was relatively resistant to midriff-baring clothing until the 1980s, it has long been a fashion with Indian women.^[14] The Japanese have long had a special regard for the navel. During the early Jomon period in northern Japan, three small balls indicating the breasts and navel were pasted onto flat clay objects to represent the female body. The navel was exaggerated in size, informed by the belief that the navel symbolizes the center of where life begins.^[15]

See also

References

Wikimedia Commons has media related to Human navel.

Look up umbilicus in Wiktionary, the free dictionary.