The human areola (''areola mammae'', or ) is the

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

ed area on the

breast The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryology, embryological tissues. The relative size and development of the breasts is ...

around the

nipple The nipple is a raised region of tissue on the surface of the breast from which, in lactating females, breast milk, milk from the mammary gland leaves the body through the lactiferous ducts to Breastfeeding, nurse an infant. The milk can flow th ...

. More generally, an areola is a small circular area on the

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anim ...

with a different

histology Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

from the surrounding tissue, or other small circular areas such as an inflamed region of skin. The mature human female nipple has several small openings arranged radially around the tip of the

lactiferous duct Lactiferous ducts are ducts that converge and form a Morphogenesis#Branching morphogenesis, branched system connecting the nipple to the lobules of the mammary gland. When lactogenesis occurs, under the influence of hormones, the breast milk, mil ...

s, from which milk is released during

lactation Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The process ...

. The other small openings in the areola are

sebaceous gland A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in ...

s, also known as areolar glands.

Shade

The areolae can range from pink to red to brown to dark brown or nearly black, but generally tend to be paler among people with lighter skin tones and darker among people with darker skin tones. A reason for the differing color may be to make the nipple area more visible to the infant.

Hyperpigmentation Hyperpigmentation, also known as the dark spots or circles on the skin, is the darkening of an area of Human skin, skin or nail (anatomy), nails caused by increased melanin. Causes Hyperpigmentation can be caused by sun damage, inflammation, or ...

occurs in most women during the second stage of pregnancy, leading to a temporarily darker shade.

Size and shape

The size and shape of areolae and

s are also highly variable, with those of women usually being larger than those of men and prepubescent girls. Human areolae are mostly circular in shape, but many women have large areolae that are noticeably elliptical. The average

diameter In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...

of male areolae is around . Sexually mature women have an average of , but sizes can exceed . Lactating women, and women with particularly large breasts, may have even larger areolae. A function of the specialized dermis of the areola is to protect the regular breast skin from wear, cracking, and irritation. Infants sometimes create trauma to the nipple and areolae by latching-on. Rated according to the

Tanner scale The Tanner scale (also known as the Tanner stages or sexual maturity rating (SMR)) is a scale of physical development as pre-pubescent children transition into adolescence, and then adulthood. The scale defines physical measurements of devel ...

of female physical development, the areolae enlarge during stage 3, but they show no separation of contour. During stage 4, the areolae and papillae rise above breast level and form secondary mounds. By stage 5, the breasts have fully developed. As this has resulted in recession of the areolae, the papillae may reach a little above the breasts' contour. Pregnancy can cause enlargement of the areola tissue and of Montgomery glands or tubercles.

Mechanoreceptors

Breastfeeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Orga ...

by the baby stimulates slowly and rapidly adapting

mechanoreceptor A mechanoreceptor, also called mechanoceptor, is a sensory receptor that responds to mechanical pressure or distortion. Mechanoreceptors are located on sensory neurons that convert mechanical pressure into action potential, electrical signals tha ...

s that are densely packed around the areolar region.

Diseases

Paget's disease of the breast is a malignant condition that outwardly may have the appearance of

eczema Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

, with skin changes involving the areola and nipple.

References

{{Authority control Breast anatomy

Shade

Size and shape

Mechanoreceptors

Diseases

See also

References