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{{about|the anatomical structure||Nipple (disambiguation)}}
{{pp-semi|small=yes}}
{{short description|Part of the breast}}
{{Infobox anatomy
| Name        = Nipple
| Latin       = papilla mammaria
| Image       = Closeup of female breast.jpg
| Caption     = A nipple, [[areola]] and [[breast]] of a female human
| Width       = 350
| Image2      =
| Caption2    = The dark pigmented [[areola]] surrounding a nipple of a young female human
| part_of     = [[Breast]]
| Precursor   =
| System      =
| Artery      =
| Vein        =
| Nerve       =
| Lymph       =
}}
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 duct]]s to [[Breastfeeding|nurse]] an infant.<ref>{{cite web|url=http://www.thefreedictionary.com/nipple|title=nipple|access-date=4 August 2017|via=The Free Dictionary}}</ref>{{sfn |Hansen|2010|p=80}} The milk can flow through the nipple passively, or it can be ejected by [[smooth muscles|smooth]] [[muscular contraction|muscle contractions]] that occur along with the ductal system. The nipple is surrounded by the [[areola]], which is often a darker colour than the surrounding skin.<ref>{{cite web |title=nipple |url=https://www.tabers.com/tabersonline/view/Tabers-Dictionary/762857/1/nipple&ti=0 |access-date=12 August 2017 |website=Taber's Online}}</ref>

Male mammals also have nipples but without the same level of function or prominence. 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, female nipples are [[sexualize]]d,<ref name="auto">{{cite web |author=Beer |first=Todd |date=2015-05-12 |title=Social Construction of the Body: The Nipple |work=SOCIOLOGYtoolbox |url=http://sociologytoolbox.com/social-construction-of-the-body/ |archive-url=https://web.archive.org/web/20150527024111/http://sociologytoolbox.com/social-construction-of-the-body/ |archive-date=May 27, 2015 |access-date=2015-05-16 }}</ref> or regarded as sex objects and evaluated in terms of their physical characteristics and sex appeal.<ref name="Dewar">{{cite web |last=Dewar |first=Gwen |date=October 2012 |title=The sexualization of girls: Is the popular culture harming our kids? |url=http://www.parentingscience.com/sexualization-of-girls.html |website= |publisher=Parenting Science}}</ref> 

==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 [[Proto-Germanic|Germanic origin]].<ref>{{cite web
| last = Harper
| first = Douglas
| author-link = Douglas Harper
| title = nipple
| work = Online Etymological Dictionary
| date = 2001–2010
| url = http://www.etymonline.com/index.php?term=nipple
| access-date = 15 August 2011 }}</ref> 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]].<ref>{{cite web
| last = Harper
| first = Douglas
| author-link = Douglas Harper
| title = teat
| work = Online Etymological Dictionary
| date = 2001–2010
| url = http://www.etymonline.com/index.php?term=teat
| access-date = 15 August 2011 }}</ref><ref>{{cite web
| last = Harper
| first = Douglas
| author-link = Douglas Harper
| title = tit (1)
| work = Online Etymological Dictionary
| date = 2001–2010
| url = http://www.etymonline.com/index.php?term=tit
| access-date = 15 August 2011}}</ref>

== Structure ==
[[File:Breast anatomy normal scheme.png|thumb|The breast: cross-section scheme of the [[mammary gland]]: {{ordered list |[[Thoracic wall|Chest wall]] |[[Pectoralis major muscle|Pectoralis muscle]]s |[[Lobe (anatomy)|Lobules]] |'''Nipple''' |[[Areola]] |[[Lactiferous duct|Milk duct]] |[[Adipose tissue|Fatty tissue]] |[[Human skin|Skin]]}}]]

In [[mammal]]s, a nipple (also called mammary papilla or [[teat]]) is a small projection of [[skin]] containing the outlets for 15–20 [[lactiferous duct]]s arranged cylindrically around the tip. [[Marsupial]]s and [[Eutheria|eutherian mammals]] typically have an even number of nipples arranged bilaterally, from as few as 2 to as many as 19.<ref>{{cite web |last=Ramel |first=Gordon |title=Mammalian Milk & Nutritional Profile of the Milk of Various Mammals |url=http://www.earthlife.net/mammals/milk.html |access-date=2013-05-09 |publisher=Earth Life}}</ref>

<!--Sensation-->The skin of the nipple is rich in a supply of special [[nerve]]s that are sensitive to certain stimuli: these are slowly-adapting and rapidly-adapting [[integumentary|cutaneous]] [[mechanoreceptor]]s. Mechanoreceptors are identified respectively by Type&nbsp;I slowly-adapting with multiple [[Merkel corpuscle end-organ]]s and Type&nbsp;II slowly-adapting with single [[Ruffini corpuscle end-organ]]s, as well as Type&nbsp;I rapidly-adapting with multiple [[Meissner corpuscle end-organ]]s and Type&nbsp;II rapidly-adapting with single [[Pacinian corpuscle end-organs]]. The dominant nerve supply to the nipple comes from the lateral cutaneous branches of fourth [[intercostal nerve]].<ref>Grabb & Smith's Plastic Surgery 6th edition. Chapter 59 page 593</ref> The nipple is also used as an anatomical landmark. It marks the T4 (fourth thoracic vertebra) [[dermatome (anatomy)|dermatome]] and rests over the approximate level of the diaphragm.{{sfn|Hansen|2010|p=73}}

<!--Blood and lymphatic supply-->The arterial supply to the nipple and breast originates from the anterior intercostal branches of the internal thoracic (mammary) arteries; lateral thoracic artery; and thoracodorsal arteries. The venous vessels parallel the arteries.{{sfn|Hansen|2010|p=80}} The lymphatic ducts that drain the nipple are the same for the breast.{{sfn|Hansen|2010|p=80}} The axillary nodes are the apical axillary nodes, the lateral group and the anterior group.<ref>{{cite book |last=Imwold |first=Denise |url=https://archive.org/details/anatomicasbodyat0000unse_n0u2 |title=Anatomica's body atlas |publisher=Laurel Glen |year=2003 |isbn=978-1-57145-923-7 |location=San Diego, CA |pages=286–7 |url-access=registration}}</ref> 75% of the lymph is drained through the axillary lymph nodes located near the armpit. The rest of the drainage leaves the nipple and breast through infroclavicular, pectoral, or parasternal nodes.

Since nipples change throughout the life span in men and women, the anatomy of the nipple can change and this change may be expected and considered normal.{{cn|date=November 2021}}

===In male mammals===<!-- this section is target of [[:Male nipple]] redirect; update that link if you rename this section -->
[[File:Nipple of male human.jpg|thumb|Nipple of a human male]]
Almost all [[mammals]] have nipples. Why males have nipples has been the subject of scientific research.  Differences among the sexes (called [[sexual dimorphism]]) within a given species are considered by [[evolutionary biologist]]s to be mostly the result of [[sexual selection]], directly or indirectly. There is a consensus that the male nipple exists because there is no particular advantage to males losing the trait. In consequence, some biologists would call the male nipple a [[Spandrel (biology)|spandrel]].<ref>{{cite journal|last1=Lawrence|first1=Eleanor|title=Why do men have nipples?|journal=Nature News|date=5 August 1999|doi=10.1038/news990805-1|url=http://www.nature.com/news/1999/990805/full/news990805-1.html|language=en|url-access=subscription}}</ref><ref>{{cite web|last1=Burke|first1=Anna|title=Do Male Dogs Have Nipples?|url=http://www.akc.org/content/dog-care/articles/do-male-dogs-have-nipples/|website=American Kennel Club|language=en|date=July 19, 2017}}</ref><ref>{{cite news|last1=Simons|first1=Andrew M.|title=Why do men have nipples?|url=https://www.scientificamerican.com/article/why-do-men-have-nipples/|work=Scientific American|date=January 13, 2003|language=en}}</ref>

In humans, the nipples are often surrounded by [[body hair]].

==Function==
[[File:Breastfeeding infant.jpg|thumb|Infant [[Latch (breastfeeding)|latched on]] to a nipple to [[breastfeed]]]]
[[File:Smoczek od butelki.JPG|thumb|Silicone teat or nipple, used for [[Baby bottle|bottle feeding]] ]]
{{main|Breastfeeding}}

The physiological purpose of nipples is to deliver [[milk]], produced in the female [[mammary gland]]s during [[lactation]], to an [[infant]]. During breastfeeding, nipple stimulation by an infant will stimulate the release of [[oxytocin]] from the [[hypothalamus]]. Oxytocin is a [[hormone]] that increases during pregnancy and acts on the breast to help produce the [[milk ejection reflex|milk-ejection reflex]]. Oxytocin release from the nipple stimulation of the infant causes the uterus to contract even after childbirth.{{sfn|Henry|2016|p=117}}<ref>{{cite web|url=https://www.womenshealth.gov/glossary/#o|title=Glossary - womenshealth.gov|website=womenshealth.gov|access-date=12 August 2017|date=2017-01-10}}{{PD-notice}}</ref> The strong uterine contractions that are caused by the stimulation of the mother's nipples help the uterus contract to clamp down the uterine arteries. These contractions are necessary to prevent [[post-partum hemorrhage|post-partum haemorrhage]].<ref name=Abedi2016>{{cite journal|last1=Abedi|first1=P|last2=Jahanfar|first2=S|last3=Namvar|first3=F|last4=Lee|first4=J|title=Breastfeeding or nipple stimulation for reducing postpartum haemorrhage in the third stage of labour|journal=The Cochrane Database of Systematic Reviews|date=27 January 2016|volume=1|issue=1|article-number=CD010845|pmid=26816300|doi=10.1002/14651858.CD010845.pub2|pmc=6718231}}</ref>

When the infant suckles or stimulates the nipple, oxytocin levels rise and small muscles in the breast contract, moving the milk through the milk ducts. The result of nipple stimulation by the infant helps to move breast milk out through the ducts and to the nipple. This contraction of milk is called the "let-down reflex".<ref>{{cite web |url=https://www.womenshealth.gov/files/documents/your-guide-to-breastfeeding.pdf |title=Guide to breastfeeding |website=www.womenshealth.gov |access-date=2017-08-12 |archive-date=2020-10-17 |archive-url=https://web.archive.org/web/20201017113931/https://www.womenshealth.gov/files/documents/your-guide-to-breastfeeding.pdf }}</ref> Latching on refers to the infant fastening onto the nipple to breastfeed. A good attachment is when the bottom of the areola (the area around the nipple) is in the infant's mouth and the nipple is drawn back inside his or her mouth. A poor latch results in insufficient nipple stimulation to create the let down reflex. The nipple is poorly stimulated when the baby latches on too close to the tip of the nipple. This poor attachment can cause sore and [[cracked nipple]]s and a reluctance of the mother to continue to breastfeed.<ref name = whgov>{{cite web |url=https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/breastfeeding-checklist-how-to-get-good-latch.html |title=Breastfeeding checklist: How to get a good latch |publisher=WomensHealth.gov |access-date=4 August 2017 |date=2017-06-09 |archive-date=2017-08-04 |archive-url=https://web.archive.org/web/20170804173646/https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/breastfeeding-checklist-how-to-get-good-latch.html }}{{PD-notice}}</ref><ref name = whgov2>{{cite web|url=https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/common-questions-about-breastfeeding-pain.html|title=Common questions about breastfeeding and pain|publisher=womenshealth.gov|access-date=4 August 2017|date=2017-06-09|archive-date=2017-08-04|archive-url=https://web.archive.org/web/20170804173525/https://www.womenshealth.gov/itsonlynatural/overcoming-challenges/common-questions-about-breastfeeding-pain.html}}{{PD-notice}}</ref> After birth, the milk supply increases based upon the continuous and increasing stimulation of the nipple by the infant. If the baby increases nursing time at the nipple, the mammary glands respond to this stimulation by increasing milk production.

==Clinical significance==
===Pain===

[[Nipple tenderness|Nipple pain]] can be a disincentive for breastfeeding.<ref>{{cite web|url=https://www.who.int/mediacentre/news/releases/2013/world_breastfeeding_week_20130730/en/|archive-url=https://web.archive.org/web/20130806074415/http://www.who.int/mediacentre/news/releases/2013/world_breastfeeding_week_20130730/en/|archive-date=August 6, 2013|title=WHO - Breastfeeding: Only 1 in 5 countries fully implement WHO's infant formula Code|website=www.who.int|access-date=12 August 2017}}</ref> Sore nipples that progress to cracked nipples is of concern since many women cease [[Nipple pain in breastfeeding|breastfeeding due to the pain]]. In some instances, an ulcer will form on the nipple.<ref name="Sant2016">{{cite journal|last1=Santos|first1=Kamila Juliana da Silva|last2=Santana|first2=Géssica Silva|last3=Vieira|first3=Tatiana de Oliveira|last4=Santos|first4=Carlos Antônio de Souza Teles|last5=Giugliani|first5=Elsa Regina Justo|last6=Vieira|first6=Graciete Oliveira|title=Prevalence and factors associated with cracked nipples in the first month postpartum|journal=BMC Pregnancy and Childbirth|volume=16|issue=1|page=209|year=2016|issn=1471-2393|doi=10.1186/s12884-016-0999-4|pmid=27496088|pmc=4975913 |doi-access=free }}</ref> 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.<ref name = nhs2>{{cite web|url=http://www.nhs.uk/Conditions/pregnancy-and-baby/Pages/sore-cracked-nipples-breastfeeding.aspx|title=Sore or cracked nipples when breastfeeding, Pregnancy and baby guide|publisher=National Health Services (UK)|website=www.nhs.uk|access-date=4 August 2017|date=2017-12-21|archive-date=2017-08-23|archive-url=https://web.archive.org/web/20170823174759/http://www.nhs.uk/conditions/pregnancy-and-baby/pages/sore-cracked-nipples-breastfeeding.aspx}}</ref> Herpes infection of the nipple is painful.{{sfn|Walker|2011|p=533}} Nipple pain can also be caused by excessive [[friction]] of clothing against the nipple that causes a [[Fissure of the nipple|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.<ref name = medline1/><ref>{{cite web|url=http://www.mayoclinic.org/symptoms/nipple-discharge/basics/definition/sym-20050946|title=Nipple discharge|publisher=[[Mayo Clinic]]|access-date=12 August 2017}}</ref>

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:<ref name = medline1>{{cite web|url=https://medlineplus.gov/ency/article/001515.htm|title=Nipple discharge: MedlinePlus Medical Encyclopedia|website=medlineplus.gov|access-date=12 August 2017}}{{PD-notice}}</ref>
* Pregnancy
* Recent breastfeeding
* [[Fissure of the nipple|Rubbing]] on the area from a bra or T-shirt
* Injury to the breast
* [[Mastitis|Infection]]
* Inflammation and [[blocked milk duct|clogging]] of the breast ducts
* Noncancerous [[pituitary tumor]]s
* Small [[breast mass|growth]] in the breast (usually not cancer)
* Severe underactive thyroid gland ([[hypothyroidism]])
* [[Fibrocystic breast changes|Fibrocystic breast]] (normal lumpiness in the breast)
* Use of certain medicines
* Use of certain herbs, such as anise and fennel
* [[Duct ectasia of breast|Widening of the milk ducts]]<ref name = medline1/>

Sometimes, babies can have nipple discharge. This is caused by hormones from the mother before birth. It usually goes away in two weeks. Cancers such as [[Paget's disease of the breast|Paget's disease]] (a rare type of cancer involving the skin of the nipple) can also cause nipple discharge.<ref name = medline1/>

Nipple discharge that is not normal is bloody, comes from only one nipple, or comes out on its own without squeezing or touching the nipple. Nipple discharge is more likely to be normal if it comes out of both nipples or happens when the nipples are squeezed. Squeezing the nipple to check for discharge can make it worse. Leaving the nipple alone may make the discharge stop.<ref name = medline1/>

Nipple discharge in a male is usually of more concern. Most of the time a mammogram and an examination of the fluid is done. A biopsy is often performed. A fine needle aspiration (FNA) biopsy can be fast and least painful. A very thin, hollow needle and slight suction will be used to remove a small sample from under the nipple. Using a local anesthetic to numb the skin may not be necessary since a thin needle is used for the biopsy. Receiving an injection to prevent pain from the biopsy may be more painful than the biopsy itself.<ref>{{cite web|url=https://www.cancer.org/cancer/breast-cancer-in-men/detection-diagnosis-staging/how-diagnosed.html|title=How Is Breast Cancer in Men Diagnosed?|website=www.cancer.org|access-date=12 August 2017}}</ref>

Some men develop a condition known as [[gynecomastia]], in which the breast tissue under the nipple develops and grows. Discharge from the nipple can occur. The nipple may swell in some men possibly due to increased levels of estrogen.<ref>{{Cite journal|last1=Cuhaci|first1=Neslihan|last2=Polat|first2=Sefika Burcak|last3=Evranos|first3=Berna|last4=Ersoy|first4=Reyhan|last5=Cakir|first5=Bekir|date=2014|title=Gynecomastia: Clinical evaluation and management|journal=Indian Journal of Endocrinology and Metabolism|volume=18|issue=2|pages=150–158|doi=10.4103/2230-8210.129104|issn=2230-8210|pmc=3987263|pmid=24741509 |doi-access=free }}</ref>

===Appearance===
[[File:DSC0216 Burma Chin Village near Lemro River Pretty little girl (7374973732).jpg|thumb|Prior to [[puberty]], the nipples on girls are very similar to boys.]]

Changes in appearance may be normal or related to disease.
* [[Inverted nipple]]s – This is normal if the nipples have always been indented inward and can easily point out when touched. If the nipples are pointing in and this is new, this is an unexpected change.
* Skin puckering of the nipple – This can be caused by scar tissue from surgery or an infection. Often, scar tissue forms for no reason. Most of the time this issue does not need treatment. This is an unexpected change. This change can be of concern since puckering or retraction of the nipple can indicate an underlying change in breast tissue that may be cancerous.{{sfn|Hansen|2010|p=83}}
* The nipple is warm to the touch, red or painful – This can be an infection. It is rarely due to breast cancer.
* Scaly, flaking, or itchy nipple – This is most often due to [[dermatitis|eczema]] or a bacterial or fungal infection. This change is not expected. Flaking, scaly, or itchy nipples can be a sign of Paget's disease.
* Thickened skin with large pores – This is called [[peau d'orange]] because the skin looks like an orange peel. An infection in the breast or inflammatory breast cancer can cause this problem. This is not an expected change.
* Retracted nipples – The nipple was raised above the surface but changes, begins to pull inward, and does not come out when stimulated.<ref>{{cite web|url=https://medlineplus.gov/ency/patientinstructions/000622.htm|title=Breast skin and nipple changes: MedlinePlus Medical Encyclopedia|website=medlineplus.gov|access-date=12 August 2017}} {{PD-notice}}</ref>
The average projection and size of human female nipples is slightly more than {{convert|3/8|in}}.<ref>M. Hussain, L. Rynn, C. Riordan and P. J. Regan, "Nipple-areola reconstruction: outcome assessment"; ''European Journal of Plastic Surgery'', Vol. 26, Num. 7, December, 2003</ref>

===Breast cancer===
Symptoms of [[breast cancer]] can often be seen first by changes of the nipple and areola, although not all women have the same symptoms, and some people do not have any signs or symptoms at all. A person may find out they have breast cancer after a routine [[mammogram]].
Warning signs can include:<ref name = cdcbc/><ref name = cdc2bc>{{cite web|url=https://www.cdc.gov/cancer/dcpc/resources/features/breastcanceryoungwomen/index.htm|title=Breast Cancer in Young Women|access-date=12 August 2017|date=September 8, 2016 |website=CDC |archive-url=https://web.archive.org/web/20170926020431/https://www.cdc.gov/cancer/dcpc/resources/features/breastcanceryoungwomen/index.htm |archive-date= Sep 26, 2017 }}{{PD-notice}}</ref>
* New lump in the nipple, or breast or armpit
* Thickening or swelling of part of the breast, areola, or nipple
* Irritation or dimpling of breast skin
* Redness or flaky skin in the nipple area or the breast
* Pulling in of the nipple or pain in the nipple area
* Nipple discharge other than breast milk, including blood
* Any change in the size or the shape of the breast or nipple
* Pain in any area of the breast<ref name = cdcbc/><ref name = cdc2bc/>

Changes in the nipple are not necessarily symptoms or signs of breast cancer. Other conditions of the nipple can mimic the signs and symptoms of breast cancer.<ref name = cdcbc>{{cite web|url=https://www.cdc.gov/cancer/breast/young_women/bringyourbrave/breast_cancer_young_women/symptoms.htm|title= Bring Your Brave Campaign - Symptoms of Breast Cancer|website=CDC |access-date=12 August 2017}}{{PD-notice}}</ref>

===Vertical transmission===
Some infections are transmitted through the nipple, especially if irritation or injury to the nipple has occurred. In these circumstances, the nipple itself can become infected with [[Candidiasis|Candida]] that is present in the mouth of the breastfeeding infant. The infant will transmit the infection to the mother. Most of the time, this infection is localized to the area of the nipple. In some cases, the infection can progress to become a full-blown case of [[mastitis]] or breast infection.<ref>{{cite web |url=https://www.who.int/hiv/pub/guidelines/nepal_art.pdf?ua=1 |title=National Anti-retroviral Therapy Guidelines |date=2009 |agency=National Centre for AIDS & STD Control  |website=World Health Organization |format=PDF |access-date=2020-10-05 |archive-date=2020-05-25 |archive-url=https://web.archive.org/web/20200525205408/https://www.who.int/hiv/pub/guidelines/nepal_art.pdf?ua=1 }}</ref> In some cases, if the mother has an infection with no nipple cracks or ulcerations, it is still safe to breastfeed the infant.

[[Herpes infection]] of the nipple can go unnoticed because the lesions are small but usually are quite painful. Herpes in the newborn is a serious and sometimes fatal infection.{{sfn|Walker|2011|p=533}} Transmission of Hepatitis C and B to the infant can occur if the nipples are cracked.<ref>{{cite web|url=https://medlineplus.gov/ency/patientinstructions/000803.htm|title=Breastfeeding vs. Formula Feeding |website=MedlinePlus Medical Encyclopedia |access-date=12 August 2017}}</ref>

Other infections can be transmitted through a break of the skin of the nipple and can infect the infant.

===Other disorders===
{{div col|colwidth=30em}}
* [[Nipple bleb]]
* [[Candida infection]] of the nipple
* Eczema of the nipple
* [[Inverted nipple]]
* [[Staphylococcus]] infection of the nipple
* [[Edematous areola]]{{sfn|Walker|2011|p=524}}
* [[Herpes infection]] of the nipple
* [[Reynaud phenomenon of the nipple]]{{sfn|Walker|2011|p=533}}
* [[Flat nipple]]{{sfn|Walker|2011|p=530}}
{{div col end}}

===Surgery===
A [[Nipple delay|nipple-sparing/subcutaneous mastectomy]] is a surgical procedure where breast tissue is removed, but the nipple and areola are preserved. This procedure was historically done only prophylactically or with mastectomy for the benign disease over the fear of increased cancer development in retained areolar ductal tissue. Recent series suggest that it may be an oncologically sound procedure for tumours not in the subareolar position.<ref name="pmid12832974">{{cite journal  |vauthors=Gerber B, Krause A, Reimer T, etal |title=Skin-sparing mastectomy with conservation of the nipple-areola complex and autologous reconstruction is an oncologically safe procedure |journal=Ann. Surg. |volume=238 |issue=1 |pages=120–7 |year=2003 |pmid=12832974 |doi= 10.1097/01.SLA.0000077922.38307.cd|pmc=1422651}}</ref><ref name="pmid17269590">{{cite journal |vauthors=Mokbel R, Mokbel K |title=Is it safe to preserve the nipple areola complex during skin-sparing mastectomy for breast cancer? |journal=Int J Fertil Female's Med |volume=51 |issue=5 |pages=230–2 |year=2006 |pmid=17269590 }}</ref><ref name="pmid17084333">{{cite journal  |vauthors=Sacchini V, Pinotti JA, Barros AC, etal |title=Nipple-sparing mastectomy for breast cancer and risk reduction: oncologic or technical problem? |journal=J. Am. Coll. Surg. |volume=203 |issue=5 |pages=704–14 |year=2006 |pmid=17084333 |doi=10.1016/j.jamcollsurg.2006.07.015 }}</ref>

==Society and culture==
[[File:Duplessis's semi-topless portrait of the Princess of Lamballe dates from 18th Century France.png|thumb|200px|[[Joseph Duplessis|Duplessis]]'s portrait of [[Marie Thérèse Louise of Savoy, Princesse de Lamballe|Marie Thérèse Louise of Savoy]] baring a nipple dates from 18th-century France.]]

===Exposure===
{{Main|Toplessness}}

The cultural tendency to hide the female nipple under clothing has existed in Western culture since the 1800s.<ref name="auto"/><ref name=Dewar/><ref name = bbc1>{{Cite news|url=https://www.bbc.com/news/magazine-30052071|title=Toplessness - the one Victorian taboo that won't go away|date=15 November 2014|access-date=13 August 2017|newspaper=BBC News}}</ref> As female nipples are often perceived an [[intimate part]], covering them might have originated under [[Victorian morality]] as with riding side saddle. Exposing the entire breast and nipple is a form of protest for some and a crime for others.<ref name = bbc1/><ref name="citypaper">{{cite web|url=http://www.washingtoncitypaper.com/columns/straight-dope/article/13045218/why-are-women-expected-to-keep-their-nipples-covered-breasts|title=Why Are Women Expected to Keep Their Nipples Covered?|date=14 February 2014|access-date=13 August 2017}}</ref> The exposure of nipples is usually considered [[Modesty|immodest]] and in some instances is viewed as [[lewd]] or [[indecent exposure|indecent]] behavior.<ref>D. Leder, ''The Body in Medical Thought and Practice'', page 223, Springer Science & Business Media, 1992, {{ISBN|978-0-7923-1657-2}}</ref>

A case in Erie, Pennsylvania, concerning the exposure of breasts and nipple proceeded to the [[United States Supreme Court]].<ref name="SC_Erie">{{cite web|title=Erie v. Pap's A. M., 529 U.S. 277 (2000)|url=https://supreme.justia.com/cases/federal/us/529/277/case.html|website=Justia Law|publisher=Justia|access-date=15 February 2018|language=en|date=March 2000|quote=Nudity cannot be considered an inherent form of expression.}}</ref> The Erie ordinance was regulating the nipple in public as an act that is committed when a person "knowingly or intentionally, ... appears in a state of nudity commits Public Indecency." Later in the statute, nudity is further described as an uncovered female nipple. But nipple exposure of a man was not regulated. An opinion column credited to [[Cecil Adams]] noted: "Ponder the significance of that. A man walks around bare-chested and the worst that happens is he won't get served in restaurants. But a woman who goes topless is legally in the same boat as if she'd had sex in public. That may seem crazy, but in the US it's a permissible law."<ref name="citypaper"/>

The legality around the exposure of nipples is inconsistently regulated throughout the US. Some states do not allow the visualization of any part of the breast. Other jurisdictions prohibit any female chest anatomy by banning anatomical structures that lie below the top of the areola or nipple. Such is the case in West Virginia and Massachusetts. West Virginia's regulation is very specific and is not likely to be misinterpreted, stating: "[The] display of 'any portion of the cleavage of the human female breast exhibited by a dress, blouse, skirt, leotard, bathing suit, or other wearing apparel [is permitted] provided the areola is not exposed, in whole or in part.{{'"}}<ref name="citypaper"/>

The social media site [[Instagram]] has a "no nipples" policy with exceptions: material that is not allowed includes "some photos of female nipples, but photos of post-[[mastectomy]] scarring and women actively breastfeeding are allowed. Nudity in photos of paintings and sculptures is OK, too".<ref name="Instagram_Help">{{cite web|title=Community Guidelines|url=https://help.instagram.com/477434105621119|website=help.instagram.com|publisher=Instagram|access-date=15 February 2018|language=en}}</ref> Previously, Instagram had removed images of nursing mothers. Instagram removed images of [[Rihanna]] and had her account cancelled in 2014 when she posted selfies with nipples. This was incentive for the Twitter campaign [[Free the nipple|#FreeTheNipple]].<ref>{{cite web|url=http://www.thewrap.com/instagram-clarifies-its-no-nipple-policy/|title=Instagram Clarifies Its No-Nipple Policy|date=17 April 2015|access-date=13 August 2017}}</ref>{{better source|date=September 2021}} In 2016, the Instagram page @genderless_nipples invited users to post images of nipples from both sexes, displaying close-ups of the nipples of both men and women for the purpose of spotlighting what may be inconsistency.<ref name = genderless>{{cite web|url=https://www.theverge.com/2016/12/6/13852900/genderless-nipples-instagram-censorship-policy|title=Genderless Nipples exposes Instagram's double standard on nudity|first=Amar|last=Toor|date=6 December 2016|website=The Verge|access-date=13 August 2017}}</ref> Some contributors have circumvented the policy.<ref>{{cite news|url=https://www.bbc.co.uk/news/newsbeat-40170981|title=Art student challenges 'sexist' ban on nipples on Instagram with new project - BBC Newsbeat|work=BBC News|date=6 June 2017|access-date=14 August 2017}}</ref><ref>{{Cite news|url=https://www.thedailybeast.com/articles/2014/09/09/women-it-s-time-to-reclaim-our-breasts|title=Women, It's Time to Reclaim Our Breasts|first=Emily|last=Shire|date=9 September 2014|via=www.thedailybeast.com|newspaper=The Daily Beast}}</ref> Facebook has also been struggling to define its nipple policy.<ref name = genderless/><ref>{{cite web|url=https://m.facebook.com/communitystandards/encouraging-respectful-behavior/|title=Community Standards|website=m.facebook.com|access-date=14 August 2017}}</ref><ref>{{cite web|url=https://www.foxnews.com/tech/is-facebook-going-to-start-freeing-the-nipple/|title=Is Facebook going to start freeing the nipple?|website=[[Fox News]]|date=24 October 2016|access-date=14 August 2017}}</ref>

Filmmaker [[Lina Esco]] made a film entitled ''[[Free the Nipple (film)|Free the Nipple]]'', which is about "laws against female toplessness or restrictions on images of female, but not male, nipples", which Esco states is an example of [[sexism]] in society.<ref name=beast>{{Cite news|url=http://www.thedailybeast.com/articles/2014/09/09/women-it-s-time-to-reclaim-our-breasts.html|title=Women, It's Time to Reclaim Our Breasts|first=Emily|last=Shire|date=9 September 2014|newspaper=The Daily Beast}}</ref>

<gallery widths=200 heights=200>
File:Sarah Goodridge Beauty Revealed The Metropolitan Museum of Art.jpg|''Beauty Revealed'', 1828 self-portrait by the American artist [[Sarah Goodridge]].
File:Namibie Himba 0716a.jpg|A [[Namibian]] woman going [[topless]]
</gallery>

===Sexuality===
{{Main|Nipple stimulation}}

Nipples can be sensitive to touch, and [[nipple stimulation]] can incite [[sexual arousal]].<ref name="Harvey">{{cite book|first1=John H. |last1=Harvey |first2=Amy |last2=Wenzel |first3=Susan |last3=Sprecher|title=The Handbook of Sexuality in Close Relationships|publisher=[[Psychology Press]]|isbn=978-1-135-62470-5|page=427|date=2004|access-date=August 12, 2017|url=https://books.google.com/books?id=qsl4AgAAQBAJ&pg=PA427}}</ref> Few women report experiencing [[orgasm]] from nipple stimulation.<ref name="Kinsey">{{cite book|first1=Alfred C. |last1=Kinsey |first2=Wardell B. |last2=Pomeroy |first3=Clyde E. |last3=Martin |first4=Paul H. |last4=Gebhard|title=Sexual Behavior in the Human Female|publisher=[[Indiana University Press]]|isbn=978-0-253-01924-0|page=587|date=1998|access-date=August 12, 2017|url=https://books.google.com/books?id=JHWHCgAAQBAJ&pg=PA587|quote=There are some females who appear to find no erotic satisfaction in having their breasts manipulated; perhaps half of them derive some distinct satisfaction, but not more than a very small percentage ever respond intensely enough to reach orgasm as a result of such stimulation (Chapter 5). [...] Records of females reaching orgasm from breast stimulation alone are rare.}}</ref><ref name="Boston">{{cite book|author=Boston Women's Health Book Collective|title=The New Our Bodies, Ourselves: A Book by and for Women|publisher=[[Simon & Schuster]]|isbn=978-0-684-82352-2|page=575|date=1996|access-date=August 12, 2017|url=https://books.google.com/books?id=JFI4AQAAIAAJ|quote=A few women can even experience orgasm from breast stimulation alone.}}</ref> Before Komisaruk et al.'s [[Functional magnetic resonance imaging|functional magnetic resonance]] (fMRI) research on nipple stimulation in 2011, reports of women achieving orgasm from nipple stimulation relied solely on [[anecdotal evidence]].<ref name="Smith">{{cite book|author=Merril D. Smith|title=Cultural Encyclopedia of the Breast|publisher=[[Rowman & Littlefield]]|isbn=978-0-7591-2332-8|page=71|date=2014|access-date=August 12, 2017|url=https://books.google.com/books?id=qrCCBAAAQBAJ&pg=PA71}}</ref> Komisaruk's study was the first to map the female genitals onto the sensory portion of the brain; it indicates that sensation from the nipples travels to the same part of the brain as sensations from the vagina, clitoris and cervix, and that these reported orgasms are genital orgasms caused by nipple stimulation, and may be directly linked to the genital sensory cortex ("the genital area of the brain").<ref name="Smith"/><ref name="Lehmiller">{{cite book|author=Justin J. Lehmiller|title=The Psychology of Human Sexuality|publisher=[[John Wiley & Sons]]|isbn=978-1-118-35132-1|page=120|date=2013|access-date=August 12, 2017|url=https://books.google.com/books?id=pQRgAgAAQBAJ&pg=PT120}}</ref><ref name="Komisaruk">
* {{Cite journal|author1-link=Barry Komisaruk|last1=Komisaruk |first1=B. R. |last2=Wise |first2=N. |last3=Frangos |first3=E. |last4=Liu |first4=W.-C. |last5=Allen |first5=K |last6=Brody |first6=S. |title=Women's Clitoris, Vagina, and Cervix Mapped on the Sensory Cortex: fMRI Evidence |journal=[[The Journal of Sexual Medicine]] |year=2011|doi=10.1111/j.1743-6109.2011.02388.x |volume=8|issue=10|pages=2822–30 |pmid=21797981 |pmc=3186818}}
* {{cite news |author=Stephanie Pappas |date=August 5, 2011 |title=Surprise finding in response to nipple stimulation |work=CBS News |url=http://www.cbsnews.com/news/surprise-finding-in-response-to-nipple-stimulation/}}</ref>

===Piercings===
{{Main|Nipple piercing}}
{{Excerpt|Nipple piercing}}

===In business===
Some companies and non-profit organisations have used the word ''nipple'' or images of nipples to draw attention to their product or cause.<ref name=beast/><ref>{{cite web |last=Disser |first=Nicole |date=19 August 2014|title=This New Bushwick Bar Is the Most Literal Boobie Trap We've Ever Seen |url=http://bedfordandbowery.com/2014/08/this-new-bushwick-bar-is-the-most-literal-boobie-trap-weve-ever-seen/ |website=Bedford and Bowery}}</ref>

==See also==
{{Div col}}
* [[Breast milk]]
* [[Fleischer's syndrome]]
* [[Nipple prosthesis]] for breast cancer survivors
* [[Pasties]]
* [[Super Bowl XXXVIII halftime show controversy]]
* [[Supernumerary nipple|Supernumerary (third) nipple]]
* [[Udder]]
* [[Wardrobe malfunction]]
{{Div col end|3}}

==References==
'''Citations'''
{{Reflist}}

'''Bibliography'''
* {{cite book | last = Davidson | first = Michele | title = Fast facts for the antepartum and postpartum nurse: a nursing orientation and care guide in a nutshell | publisher = Springer Publishing Company, LLC | location = New York, NY | year = 2014 | isbn = 978-0-8261-6887-0 }}
* {{cite book | last = Durham | first = Roberta | title = Maternal-newborn nursing: the critical components of nursing care | publisher = F.A. Davis Company | location = Philadelphia | year = 2014 | isbn = 978-0-8036-3704-7 }}
* {{cite book | last = Hansen | first = John | title = Netter's clinical anatomy | publisher = Saunders/Elsevier | location = Philadelphia | year = 2010 | isbn = 978-1-4377-0272-9 }}
* {{cite book | last = Henry | first = Norma | title = RN maternal newborn nursing: review module | publisher = Assessment Technologies Institute | location = Stilwell, KS | year = 2016 | isbn = 978-1-56533-569-1 }}
* {{cite book |first1=Ruth A. |last1=Lawrence|first2=Robert M. |last2=Lawrence |title=Breastfeeding: A Guide for the Medical Professional |url={{google books |plainurl=y |id=S6y6CgAAQBAJ|page=227}}|date=13 October 2015|pages=227–8|publisher=Elsevier Health Sciences|isbn=978-0-323-39420-8}}
* {{cite book|title=Breastfeeding management for the clinician: using the evidence |last=Walker |first=Marsha|publisher=Jones and Bartlett Publishers |year=2011|isbn=978-0-7637-6651-1 |location=Sudbury, Mass}}

== External links ==
{{Wiktionary|nipple|teat|papilla}}
* {{Commons category inline|Nipples}}
* {{Wikiquote inline}}

{{Breast anatomy|state=collapsed}}
{{Disorders of the breast}}
{{sex}}
{{Human regional anatomy}}
{{Authority control}}

[[Category:Nipple| ]]
[[Category:Breast milk| ]]
[[Category:Breast]]
[[Category:Breastfeeding]]
[[Category:Embryology]]
[[Category:Exocrine system]]
[[Category:Glands]]
[[Category:Human sexuality]]
[[Category:Mammal anatomy]]
[[Category:Midwifery]]
[[Category:Secondary sexual characteristics]]