Belly button

Navel
The human navel is a raised or hollowed area left after the umbilical cord detaches.
Details
Precursor	Umbilical cord Ductus venosus
Artery	Umbilical artery
Vein	Umbilical vein
Identifiers
Latin	Umbilicus
MeSH	D014472
Dorlands /Elsevier	u_02/12836058
TA	A01.2.04.005
FMA	61584
Anatomical terminology []

The navel (clinically known as the umbilicus, colloquially known as the belly button, or tummy button) is a hollowed or sometimes raised area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel.

The umbilicus is used to visually separate the abdomen into quadrants.

The umbilicus is a prominent mark on the abdomen, with its position being relatively consistent among 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, with a normal variation among people between the L3 and L5 vertebrae.

Parts of the navel include the "umbilical tip", which is the center of the navel often described as a button shape. The "periumbilical skin" surrounds it. Navels consisting of the umbilical tip protruding past the periumbilical skin have been nicknamed "outies". Outies are often mistaken for umbilical hernias, but are actually a completely different shape with no health concern, unlike an umbilical hernia. The navel (specifically abdominal wall) would be considered an umbilical hernia if the protrusion was 5 centimeters or more. The total diameter of an umbilical hernia is usually 10 centimeters.

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.

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.

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