Earlobe
Latin	lobulus auriculae (singular), lobulii auricularum (plural)
Gray's	subject #229 1034
System	Auditory system
Dorlands/Elsevier	l_13/12500813

On the ear of humans and many other animals, the earlobe('lobulus auriculæ'), sometimes simply lobe or lobule) is the soft lower part of the external ear, similar in composition to the labia, or pinna. It is the lowermost portion of the human pinna, projecting below the antitragus. The earlobe is composed of tough areolar and adipose (fatty) connective tissues, lacking the firmness and elasticity of the rest of the pinna, since the earlobe contains no cartilage. Earlobes have a large blood supply and may help to warm the ears and maintain balance but generally earlobes are not considered to have any major biological function.^[1] Image File history File links Gray904. ... For other uses, see Latins and Latin (disambiguation). ... In biology, an organ is a group of tissues which perform some function. ... The auditory system is the sensory system for the sense of hearing. ... Elseviers logo. ... For other uses, see Ear (disambiguation). ... This article is about modern humans. ... Opposite the tragus, and separated from it by the intertragic notch, is a small tubercle, the antitragus. ... Gel-like matrix with all three fiber types Areoloar tissue is the most common connnective tissue type and can be found in the skin as well as in places that connect epithelium to other tissues. ... Adipose tissue is an anatomical term for loose connective tissue composed of energy in the form of fat, although it also cushions and insulates the body. ... Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ... Cartilage is a type of dense connective tissue. ... For other uses, see Blood (disambiguation). ...

Size and shape

Diagram showing free (left) and attached (right) earlobes.

Earlobes average about 2 cm long, and enlongate slightly with age.^[2] Human earlobes may be free or detached (hanging free from the head) or attached (joined to the head). Whether the earlobe is free or attached is a classic example of a simple genetic dominance relationship; freely hanging earlobes are the dominant allele and attached earlobes are recessive. Therefore, a person whose genes contain one allele for free earlobes and one for attached lobes will display the freely hanging lobe trait. It is a common misunderstanding that this implies a precise 3-to-1 ratio between hanging and attached lobes in the human population. Such a ratio would require that the allele frequency for hanging lobes were precisely 50%, which there is no reason to assume. One study ^[3] found that the frequency of attached ear lobes among Japanese subjects was 67.1%, and in Chinese subjects it was 64.3%. Image File history File links Earlobes_free_attached. ... In genetics, dominance describes a specific relationship between the effects of different versions of a gene (alleles) on a trait (phenotype). ...

Earlobes are normally smooth, but occasionally exhibit creases. Creased earlobes are associated with genetic disorders, including Beckwith-Wiedemann syndrome. Earlobe creases are also associated with an increased risk of heart attack and coronary heart disease; however, since earlobes become more creased with age, and older people are more likely to experience heart disease than younger people, age may account for the findings linking heart attack to earlobe creases.^[4] Beckwith-Wiedemann syndrome (BWS) is a very rare genetic overgrowth syndrome (prevalence of about 1 in 36,000). ... Heart attack redirects here. ... Coronary heart disease (CHD), also called coronary artery disease (CAD), ischaemic heart disease, atherosclerotic heart disease, is the end result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium (the muscle of the heart) with oxygen and nutrients. ...

The earlobe contains many nerve endings, and for some people is an erogenous zone. A nerve is an enclosed, cable-like bundle of nerve fibers or axons, which includes the glia that ensheath the axons in myelin. ... This article does not cite any references or sources. ...

Earlobe piercing

Tutankhamen displaying a stretched earlobe piercing.

Around the world and throughout human history, the earlobe is the most common location for a body piercing. Tearing of the earlobe from the weight of very heavy earrings, or traumatic pull of an earring, is fairly common. The repair of such a tear is usually not difficult^{[citation needed]}. Some cultures practice earlobe stretching, using piercing ornaments to stretch and enlarge the earlobes. Piercing the earlobe poses a much lower risk of infection than piercing other parts of the ear^{[citation needed]}. After that time, earrings can be changed, but if the hole is left unfilled for an extended period of time, there is a chance of the piercing closing. After healing, earlobe piercings will shrink to smaller gauges in the prolonged absence of earrings, but may never completely disappear. Download high resolution version (550x775, 58 KB)The gold funerary mask of Tutankhamun, in the Egyptian Museum, Cairo. ... Download high resolution version (550x775, 58 KB)The gold funerary mask of Tutankhamun, in the Egyptian Museum, Cairo. ... Tutankhamun (alternate transcription Tutankhamen), named Tutankhaten early in his life, was Pharaoh of the Eighteenth dynasty of Egypt (1334 BC/1333 BC - 1323 BC), during the period known as the New Kingdom. ... This article does not cite any references or sources. ... An earring with an intricate design An earring is a piece of jewelry that is worn on the ear. ... Stretched Earlobe Earlobe stretching is the practice of increasing the diameter of a standard earlobe piercing for the purpose of wearing larger gauge jewelry. ...

See also

• Otoplasty

Otoplasty cosmetic surgery to change the appearance of a persons external ears. ...

References

1. ^ Popelka, Gerald, ""Re:Why do we have earlobes, what are they for, since when?" MadSci Network, posted Aug 31 1999. [1]
2. ^ Azaria, R., et al. Morphometry of the Adult Earlobe: A Study of 547 Subjects and Clinical Application (abstract), American Society of Plastic Surgeons, 2003. [2].
3. ^ LY Lai, RJ Walsh, "Observations on ear lobe types." Acta Genet Stat Med, 1966
4. ^ U.S. National Library of Medicine and National Institute of Health, "Earlobe Creases." Medical Encyclopedia, [3]. Updated 10/20/2004.