At the apex of the breast is a circular pigmentation. The ring surrounding the central nipple, from pink to brown, with large individual variation. The diameter ranges from a few centimetres to over ten in some, and fine elevations are scattered over the surface. Nyuurin (乳輪), the areola, is anatomically an auxiliary structure of lactation function, and in the sexual context a body part whose individual variation in size and colour forms an independent axis of taste.

The areola is the circular pigmented skin region surrounding the nipple at the apex of the breast. Anatomically it is written nyū-un, Latin areola mammae, English areola. The Montgomery glands, an aggregation of sebaceous glands, are distributed there, observed as fine elevations on the surface. It is a tissue closely related to lactation function, yet a part read strongly as a sexual sign.

Anatomy and physiology

The areola is a circular skin region about 2–6 cm in diameter at the apex of the breast, with a wide range of individual variation. Its colour is distributed widely from light pink to dark brown according to skin colour, heredity, and ethnicity. With pregnancy and childbirth, pigmentation advances and the size tends to enlarge. On the surface are scattered small elevations called the Montgomery glands (areolar glands), citation needed which secrete sebum and antibacterial substances and carry the protection of the nipple during lactation.

Beneath the areolar skin lies smooth muscle, which contracts with cold, sexual arousal, or stimulation, so that the areolar surface wrinkles or the nipple becomes erect. This is an autonomic response under sympathetic-nerve control, and voluntary control is difficult. It is because of this involuntariness that it has drawn attention since antiquity as an index of sexual arousal.

Individual variation in size and colour

The size of the areola varies extremely between individuals. Even with the same large breasts, there are those with small areolae and those with large; and even with small breasts, there is no correlation with areolar size. The size of the areola has a strong aspect of being determined independently of mammary-gland development, forming the central axis of visual diversity.

The individual variation in colour is also marked. In Japanese women, the nulliparous range from light pink to reddish-brown, the parous from dark brown to blackish-brown. Because it is a part that does not tan, it readily reflects the original colour of the skin, and the contrast with skin colour becomes an object of taste. In adult works, tags thematising colour, such as “pink areola” and “darkened areola,” have differentiated, each functioning as an independent axis of taste.

Reception psychology

There are several reasons the areola holds as an independent axis of taste. First, the size of the areola is read as an index of childbirth and lactation experience. A large areola is emphasised in married-woman and mature-woman works as a sign of maturity, of the wife, of the parous; a small areola is foregrounded in lolita and schoolgirl works as a sign of youth and the nulliparous. It is a function as a sign of age and sexual experience, independent of the size of the breast itself.

Second, the colour of the areola is read as a racial and personal constitutional index. A light-pink areola becomes, as a Western and northern representation, a sign of youth and purity; dark brown becomes a sign of the southern, the Mediterranean, or of post-childbirth maturity. The tag-differentiation of “pink nipple” and “black nipple” in adult genres corresponds to an explicit taste for this colour sign. Third, the presence and density of the Montgomery glands (granular elevations) on the areolar surface also form a fine axis of taste; an areola with conspicuous elevations is, as a sign of the parous and the mature, favoured by some as a sign of a bumpy texture.

Derivative forms

• Pink areola / pale areola: light pigmentation, a sign of youth and purity
• Black areola / darkened areola: deep pigmentation, a sign of maturity and childbirth
• Large areola: large in diameter, emphasised in married-woman works
• Inverted areola: a state where the nipple is recessed below the areola, an anatomical individual variation
• Puffy areola: a state where the areola itself swells and rises, a special taste

Cultural history

The viewpoint that makes the areola an independent aesthetic object is not clear in classical shunga and ukiyo-e. The breast itself is often drawn, but the differentiation of areola and nipple was limited by the constraints of printing technique and colour expression. From the Meiji period onward, with photographic media, and especially with the spread of colour printing, the colour and size of the areola rose as objects of visual attention.

In postwar Japan, through the hair-nude photo-book boom and the development of gravure magazines, photographs of the breast came to circulate publicly, and attention to the individual variation of the areola rose. With the high-resolution adult video from the 1990s and the spread of the VR viewing environment from the 2010s, the fine details of the areolar surface became observable, and the resolution of the taste rose further.

See also

• Nipple
• Breasts (oppai)
• Large breasts
• Small breasts
• Enormous breasts