Nipple
The nipple is a raised region of tissue on the surface of the breast from which, in females, milk leaves the breast through the lactiferous ducts to breastfeed an infant.[1][2] The milk can flow through the nipple passively or it can be ejected by smooth muscle contractions that occur along with the ductal system. Male mammals also have nipples but without the same level of function, and often surrounded by body hair.
This article is about the anatomical structure. For other uses, see Nipple (disambiguation).Nipple
The nipple is surrounded by the areola, which is often a darker colour than the surrounding skin.[3] A nipple is often called a teat when referring to non-humans. "Nipple" or "teat" can also be used to describe the flexible mouthpiece of a baby bottle. In humans, the nipples of both males and females can be sexually stimulated as part of sexual arousal. In many cultures, human female nipples are sexualized,[4] or regarded as sex objects and evaluated in terms of their physical characteristics and sex appeal.[5] Some cultures have little to no sexualization of the nipple, and going topless presents no barrier.
Clinical significance
Pain
Nipple pain can be a disincentive for breastfeeding.[19] Sore nipples that progress to cracked nipples is of concern since many women cease breastfeeding due to the pain. In some instances, an ulcer will form on the nipple.[20] One reason for the development of cracked and sore nipples is the incorrect latching-on of the infant to the nipple. If a nipple appears to be wedge-shaped, white and flattened, this may indicate that the attachment of the infant is not good and there is a potential of developing cracked nipples.[21] Herpes infection of the nipple is painful.[22] Nipple pain can also be caused by excessive friction of clothing against the nipple that causes a fissure.
Discharge
Nipple discharge refers to any fluid that seeps out of the nipple of the breast. Discharge from the nipple does not occur in lactating women. And discharge in non-pregnant women or women who are not breastfeeding may not cause concern. Men that have discharge from their nipples are not typical. Discharge from the nipples of men or boys may indicate a problem. Discharge from the nipples can appear without squeezing or may only be noticeable if the nipples are squeezed. One nipple can have discharge while the other does not. The discharge can be clear, green, bloody, brown or straw-coloured. The consistency can be thick, thin, sticky or watery.[23][24]
Some cases of nipple discharge will clear on their own without treatment. Nipple discharge is most often not cancer (benign), but rarely, it can be a sign of breast cancer. It is important to determine what is causing the discharge and to get treatment. Reasons for nipple discharge include:[23]
Etymology
The word "nipple" most likely originates as a diminutive of neb, an Old English word meaning "beak", "nose", or "face", and which is of Germanic origin.[58] The words "teat" and "tit" share a Germanic ancestor. The second of the two, tit, was inherited directly from Proto-Germanic, while the first entered English via Old French.[59][60]
