Earlobes

Earlobe
Details
System	Auditory system
Identifiers
Latin	lobulus auriculae (singular), lobuli auricularum (plural)
TA	A15.3.01.003
FMA	60984
Anatomical terminology []

The human earlobe (lobulus auriculae) is composed of tough areolar and adipose connective tissues, lacking the firmness and elasticity of the rest of the auricle (the external structure of the ear). In some cases the lower lobe is connected to the side of the face. Since the earlobe does not contain cartilage it has a large blood supply and may help to warm the ears and maintain balance. The zoologist Desmond Morris in his book The Naked Ape (1967) conjectured that the lobes developed as an additional erogenous zone to facilitate the extended sexuality necessary in the evolution of human monogamous pair bonding. However, earlobes are not generally considered to have any major biological function. The earlobe contains many nerve endings, and for some people is an erogenous zone.

It might seem to be that the earlobe, as a body part built of epithelium and connective tissue, is derived from dermatome. However this is not the case, in the surrounding tissue there are no somites – thus also there is no dermatome. In this area, the dermis is derived from cells of mesenchymal cells, whereas the mesenchyme is derived from the sclerotome and splanchnopleura located in the nearby regions of the torso.

The earlobe as a body part arises and develops in the vicinity of of auricular follicle, as a result of cascade induction:

Earlobes average about 2 centimeters long, and elongate slightly with age. Although the "free" vs. "attached" appearance of earlobes is often presented as an example of a simple "one gene - two alleles" Mendelian trait in humans, earlobes do not all fall neatly into either category; there is a continuous range from one extreme to the other, suggesting the influence of several genes.

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