Online Encyclopedia Search Tool

Your Online Encyclopedia


Online Encylopedia and Dictionary Research Site

Online Encyclopedia Free Search Online Encyclopedia Search    Online Encyclopedia Browse    welcome to our free dictionary for your research of every kind

Online Encyclopedia


The female breast produces and secretes milk to feed infants.
The female breast produces and secretes milk to feed infants.

The term breasts can refer to the upper ventral region of the human torso. Alternatively the term is used for each of two parts of that, especially for women: the breasts are parts of the female human body that contain the organs that secrete milk used to feed infants. Males also have breasts and are born with the main milk ducts intact, but while the gland that produces milk is present in the male, it normally remains undeveloped. In some situations male breast development does occur, a condition called gynecomastia. Milk production can also occur in both men and women as a rare side-effect of some medicinal drugs (such as some antipsychotic medication). Both sexes have a large concentration of blood vessels and nerves in their nipples.



A woman's breasts sit over the pectoralis major muscle and usually extend from the level of the 2nd rib to the level of the 6th rib anteriorly. The superior lateral quadrant of the breast extends diagonally upwards in an 'axillary tail'. A thin layer of mammary tissue extends from the clavicle above to the seventh or eight ribs below and from the midline to the edge of the latissimus dorsi posteriorly.

Important parts of the breasts include mammary glands, the axillary tail (tumours are most likely to occur here), the lobules, Cooper's ligaments, the areola and the nipple.


In both males and females, the breasts are composed of adipose tissue and mammary glands.
In both males and females, the breasts are composed of adipose tissue and mammary glands.

It is commonly assumed by biologists that the real evolutionary purpose of women having breasts is to attract the male of the species, that in other words, breasts are secondary sex characteristics. Some biologists believe that the shape of female breasts evolved as a frontal counterpart to that of the buttocks.

Others believe that the human breast evolved in order to prevent infants from suffocating while feeding. Since human infants do not have a protruding jaw like our ancestors and the other primates, the infant's nose might be blocked by a flat female chest while feeding. According to this theory, as the human jaw became recessed, so the breasts became larger to compensate.

A common misconception is that women have breasts so that they can feed babies by producing milk. The mammary glands that secrete the milk from the breasts make up a relatively small fraction of the overall breast tissue. Most of the human female breast is actually adipose tissue (fat) and connective tissue. Breast size does not make any difference to a woman's ability to nurse a baby.

Because some cultures place a high value on symmetry of the female human form, and because women often identify their femininity and sense of self with their breasts, many women in developed countries undergo breast reconstruction after mastectomy for breast cancer.

Cultural status

A brassiere or bra is an item of women's underwear consisting of two cups covering totally or partially the breasts for support and modesty. Topless is the state of having bare breasts. For more on modesty regarding breasts see Nudity.

There are many slang terms for the breasts.

Disorders of the breasts

Infections and inflammations

  • Masbreastis
    • bacterial masbreastis
    • masbreastis from milk engorgement
    • masbreastis of mumps
    • subareolar masbreastis
  • Other infections
    • chronic intramammary abscess
    • chronic subareolar abscess
    • tuberculosis of the breast
    • syphilis of the breast
    • retromammary abscess
    • actinomycosis of the breast

Benign breast disease

  • Aberrations of normal development and involution
    • fibroadenomatosis
    • cyclical nodularity
    • cysts
    • fibroadenoma
  • Duct ectasia /Periductal masbreastis
    • nipple discharge
    • abscesses
    • mammary fistula
  • Epithelial hyperplasia *
  • Pregnancy-related
    • galactocoele
    • puerperal abscess

Metastatic breast disease

See also

External links

Last updated: 10-24-2004 05:10:45