Table of ContentsView AllTable of ContentsLayersAnatomyPhysiology
Table of ContentsView All
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Table of Contents
Layers
Anatomy
Physiology
Breast anatomy includes the nipple and areola on the outside, and milk ducts, lobes, lobules, lymph nodes, and vessels on the inside. Normal breasts can range in size, shape, appearance, and texture and may change throughout life.
When to see a healthcare providerChanges to your breasts always warrant a visit to your healthcare provider. These include:A new lump in the breastNipple dischargeChanges in the appearance of the skinA rashA nipple that turns inwardNew or unusual pain in the breast
When to see a healthcare provider
Changes to your breasts always warrant a visit to your healthcare provider. These include:A new lump in the breastNipple dischargeChanges in the appearance of the skinA rashA nipple that turns inwardNew or unusual pain in the breast
Changes to your breasts always warrant a visit to your healthcare provider. These include:
What Are the Layers of the Breast?
The female breast is made up of multiple types of tissue, including:
What area of the breast do most breast cancers develop?Most breast cancers develop in the upper part of the breast close to the armpit.
What area of the breast do most breast cancers develop?
Most breast cancers develop in the upper part of the breast close to the armpit.
Breast Anatomy
The female breast contains many different parts with varying functions.
Nipple
Paget’s disease of the nippleis a rare form of breast cancer that accounts for less than 5% of breast cancer cases. In this condition, cancer cells usually travel from the milk ducts and spread to the nipple’s surface and the areola, causing them to become itchy, red, and scaly.
What parts of the breast hurt during early pregnancy?The entire breast may be uncomfortable in early pregnancy. As hormones are changing the breasts and preparing them for milk production, the skin, lobes, and nipples may all feel uncomfortable. As the breast size increases, the ligaments in the breast stretch and may feel painful.
What parts of the breast hurt during early pregnancy?
The entire breast may be uncomfortable in early pregnancy. As hormones are changing the breasts and preparing them for milk production, the skin, lobes, and nipples may all feel uncomfortable. As the breast size increases, the ligaments in the breast stretch and may feel painful.
Areola
Surrounding the nipple is theareola, an area of skin that is darker than the rest of the breast. The average areola size is 2.5 inches in diameter, but they may be small or large, round or oval. All of these variations are normal.
During pregnancy, the areolas often grow in diameter and may remain larger (and sometimes darker) even after pregnancy.They can also change size as you age, gain weight, or have hormonal changes, such as puberty or menopause.
There are small bumps on the areola. These are either hair follicles or Montgomery glands, which are sebaceous (oil) glands.
If you notice any changes in the areola, such as dimples, puckers, or a rash, notify your healthcare provider. These might be harmless, but could also be symptoms of Paget’s disease.
Tenderness or a hard lump beneath the areola may also be symptoms of asubareolar abscess,cancer, or a noncancerous infection that may need to be drained.
Montgomery Glands
Montgomery glands are small glands that lie just below the surface of the areola and look like small bumps on the skin. Also called areolar glands or Montgomery tubercles, these provide lubrication during breastfeeding and have a scent that attracts the infant to the breast.
Montgomery glands may become blocked, like pimples, and become swollen. A cyst may develop beneath a blocked gland. This can feel uncomfortable, but it is not a sign of breast cancer.
Lobes
Each breast has 15–20 lobes that contain clusters of lobules, which produce breast milk. Each lobe has 20–40 lobules.
Invasive lobular carcinoma (ILC) accounts for 10% of breast cancers. ILC starts in the breast’s lobules and invades surrounding tissue. ILC can feel like a thick or full area that feels different than the rest of the breast.
Noncancerous conditions that can affect the lobes and lobules are lobular carcinoma in situ (LCIS) and atypical lobular hyperplasia (ALH). These consist of abnormal cells. Though they aren’t cancerous themselves, having them raises your risk of breast cancer in the future.
Glandular tissue includes the lobules, which produce breast milk, and ducts, the tubes that carry milk to the nipple.
Milk Ducts
Milk ducts are small tubes that transport milk from the milk glands (the lobules in the breast) out to the tip of the nipple.
Breast milk is released from tiny openings at the surface of the nipple. There are typically two or three of these holes in the center of your nipple, and three to five more arranged around the center. These holes have tiny sphincters (rings of muscle) that close to prevent leakage when not breastfeeding.
The ducts just below the areola widen before they enter the nipple. This wide, saclike area is called an ampulla.
During breastfeeding, a milk duct can become plugged, leading to an infection called mastitis. Mastitis can be very uncomfortable but usually responds well to heat and antibiotics.
Breast cancer can also occur in the milk ducts. Cancer beginning in the milk ducts is calledinvasive ductal carcinoma. Most breast cancers (around 80%) start in the milk ducts.Ductal carcinoma in situ, which also originates in the ducts, is a noninvasive form of ductal cancer.
Are breasts part of the reproductive system?Although breasts are not reproductive organs, they have an important function in reproductive health, as they are able to produce milk to nourish an infant.
Are breasts part of the reproductive system?
Although breasts are not reproductive organs, they have an important function in reproductive health, as they are able to produce milk to nourish an infant.
Blood Vessels
The internal mammary artery, which runs underneath the main breast tissue, is the primary source of the breast’s blood supply. The blood supply provides oxygen and nutrients to the breast tissue. Other blood vessels include thethoracoacromialartery, lateral thoracic artery, as well as capillaries and veins.
During a nipple-sparingmastectomy, a surgeon may temporarily remove and then replace the nipple in order to remove any breast cells that may contain cancer. This can, however, disrupt the tiny blood vessels, leading to loss of your nipple later on. Maintaining the blood supply in the nipple helps to keep these tissues alive after amastectomy.
Lymph Vessels
Lymph vessels transport lymph, the fluid that helps your body’s immune system fight infection. Lymph vessels connect to lymph nodes found under the armpits, in the chest, and elsewhere in the body.
A rare but aggressive type of breast cancer, calledinflammatory breast cancer(IBC), occurs when cancer cells block lymph vessels in the skin, which then causes inflammation in the breast. Symptoms of IBC include dimpling or thickening of breast skin and may look and feel like an orange peel. Other symptoms include breast swelling, itching, and breast skin that is red or purple.
The breast’s lymph system plays a role in the diagnosis and treatment of breast cancers overall. Cancer cells can travel through lymph vessels into the lymph nodes, move through the bloodstream, and spread to other organs, leading to metastasis.
Nerves
Sometimes after a mastectomy, when the full breast has been removed, there can be nerve pain or discomfort that remains, called post-mastectomy pain syndrome. This can cause numbness or tingling in the wall of the chest and occurs due to changes in the nerves that occur after surgery.
Muscles and Ligaments
The breasts lie on top of the pectoral muscles, which extend from the breastbone up to the collarbone and into the armpit. Their main purpose is to control movement in the arm and shoulder, but they are also connected to the breasts.
Hair Follicles
Hair follicles are present on the outer breast, usually on the surface of the areola. Due to these follicles, it is not unusual to have a few hairs growing on the areola or breast skin.
A condition called folliculitis can occur in the hair follicles. With folliculitis, the follicle around the hair becomes inflamed and may be red, swollen, and painful. A boil can form if an infection in the inflamed follicle goes deeper into the surface.
What are the areas of breast pain?Pain can be felt anywhere on the breast, but the most common type of breast pain is cyclical. This type of pain is related to the menstrual cycle and may be felt around the time ovulation until the start of your period. You may feel it in one or both breasts or in your underarm.
What are the areas of breast pain?
Pain can be felt anywhere on the breast, but the most common type of breast pain is cyclical. This type of pain is related to the menstrual cycle and may be felt around the time ovulation until the start of your period. You may feel it in one or both breasts or in your underarm.
Physiology of the Breast
Dense Breasts
Dense breastsare breasts that have more glandular tissue than what is average. Dense breasts are normal, but they are associated with slightly higher chances of developing breast cancer. Dense breast tissue also makes it harder to see breast cancer on a mammogram.
Male Breasts
Male breasts develop from the same cells as female breasts. Male breasts, however, have underdeveloped milk ducts. Males can develop a condition called gynecomastia, which causes enlargement of the breast tissue.
Summary
The outer part of the female breast includes the nipple and areola. Milk ducts, lobes, lobules, lymph nodes, and vessels are located on the inside of the breast.
The female breast produces milk to feed an infant, but it also plays a role in female sexuality. Many conditions can affect the breast, including cysts, mastitis, and different types of breast cancer.
26 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Breast anatomy.Canadian Cancer Society.The breasts.Zucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surg. 2016;5(1):32-36.National Organization for Rare Disorders.Pagets disease of the breast.American Pregnancy Association.Breast changes during early pregnancy.Alex A, Bhandary E, McGuire KP.Anatomy and physiology of the breast during pregnancy and lactation.Adv Exp Med Biol. 2020;1252:3-7. doi:10.1007/978-3-030-41596-9_1National Library of Medicine.Subareolar abcess.Kantha SS.Montgomery glands in the areolar region: A clinical overview.Int Med J. 2023;30(3):128-31.Susan G. Komen.Breast anatomy.American Cancer Society.Invasive breast cancer.American Cancer Society.Ductal carcinoma in situ (DCIS).Centers for Disease Control and Prevention.What does it mean to have dense breasts?University of Michigan Health.Mastitis while breastfeeding.American Cancer Society.Invasive breast cancer.National Library of Medicine.Female reproductive system.Sophia L, Singh D, Xalxo N, et al.Upper limb arterial pattern: Clinical correlation and embryological perspective.J Vasc Bras. 2021;20:e20210008. doi:10.1590/1677-5449.210008Columbia University Department of Surgery.Guide to breast cancer.American Cancer Society.Inflammatory breast cancer.Zhang S, Zhang D, Yi S, et al.The relationship of lymphatic vessel density, lymphovascular invasion, and lymph node metastasis in breast cancer: A systematic review and meta-analysis.Oncotarget. 2017;8(2):2863-2873. doi:10.18632/oncotarget.13752American Academy of Family Physicians.Breastfeeding: Tips to get you off to a good start.American Cancer Society.Post-mastectomy pain syndrome.Stonybrook University Hospital.General breast health.Johns Hopkins Medicine.Mastalgia.Johns Hopkins Medicine.Folliculitis, boils, and carbuncles.Johns Hopkins Medicine.Breast pain (mastalgia).Johns Hopkins Medicine.Gynecomastia.Additional ReadingZucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surgery. 2016;5(1):32-36.
26 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Breast anatomy.Canadian Cancer Society.The breasts.Zucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surg. 2016;5(1):32-36.National Organization for Rare Disorders.Pagets disease of the breast.American Pregnancy Association.Breast changes during early pregnancy.Alex A, Bhandary E, McGuire KP.Anatomy and physiology of the breast during pregnancy and lactation.Adv Exp Med Biol. 2020;1252:3-7. doi:10.1007/978-3-030-41596-9_1National Library of Medicine.Subareolar abcess.Kantha SS.Montgomery glands in the areolar region: A clinical overview.Int Med J. 2023;30(3):128-31.Susan G. Komen.Breast anatomy.American Cancer Society.Invasive breast cancer.American Cancer Society.Ductal carcinoma in situ (DCIS).Centers for Disease Control and Prevention.What does it mean to have dense breasts?University of Michigan Health.Mastitis while breastfeeding.American Cancer Society.Invasive breast cancer.National Library of Medicine.Female reproductive system.Sophia L, Singh D, Xalxo N, et al.Upper limb arterial pattern: Clinical correlation and embryological perspective.J Vasc Bras. 2021;20:e20210008. doi:10.1590/1677-5449.210008Columbia University Department of Surgery.Guide to breast cancer.American Cancer Society.Inflammatory breast cancer.Zhang S, Zhang D, Yi S, et al.The relationship of lymphatic vessel density, lymphovascular invasion, and lymph node metastasis in breast cancer: A systematic review and meta-analysis.Oncotarget. 2017;8(2):2863-2873. doi:10.18632/oncotarget.13752American Academy of Family Physicians.Breastfeeding: Tips to get you off to a good start.American Cancer Society.Post-mastectomy pain syndrome.Stonybrook University Hospital.General breast health.Johns Hopkins Medicine.Mastalgia.Johns Hopkins Medicine.Folliculitis, boils, and carbuncles.Johns Hopkins Medicine.Breast pain (mastalgia).Johns Hopkins Medicine.Gynecomastia.Additional ReadingZucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surgery. 2016;5(1):32-36.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.Breast anatomy.Canadian Cancer Society.The breasts.Zucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surg. 2016;5(1):32-36.National Organization for Rare Disorders.Pagets disease of the breast.American Pregnancy Association.Breast changes during early pregnancy.Alex A, Bhandary E, McGuire KP.Anatomy and physiology of the breast during pregnancy and lactation.Adv Exp Med Biol. 2020;1252:3-7. doi:10.1007/978-3-030-41596-9_1National Library of Medicine.Subareolar abcess.Kantha SS.Montgomery glands in the areolar region: A clinical overview.Int Med J. 2023;30(3):128-31.Susan G. Komen.Breast anatomy.American Cancer Society.Invasive breast cancer.American Cancer Society.Ductal carcinoma in situ (DCIS).Centers for Disease Control and Prevention.What does it mean to have dense breasts?University of Michigan Health.Mastitis while breastfeeding.American Cancer Society.Invasive breast cancer.National Library of Medicine.Female reproductive system.Sophia L, Singh D, Xalxo N, et al.Upper limb arterial pattern: Clinical correlation and embryological perspective.J Vasc Bras. 2021;20:e20210008. doi:10.1590/1677-5449.210008Columbia University Department of Surgery.Guide to breast cancer.American Cancer Society.Inflammatory breast cancer.Zhang S, Zhang D, Yi S, et al.The relationship of lymphatic vessel density, lymphovascular invasion, and lymph node metastasis in breast cancer: A systematic review and meta-analysis.Oncotarget. 2017;8(2):2863-2873. doi:10.18632/oncotarget.13752American Academy of Family Physicians.Breastfeeding: Tips to get you off to a good start.American Cancer Society.Post-mastectomy pain syndrome.Stonybrook University Hospital.General breast health.Johns Hopkins Medicine.Mastalgia.Johns Hopkins Medicine.Folliculitis, boils, and carbuncles.Johns Hopkins Medicine.Breast pain (mastalgia).Johns Hopkins Medicine.Gynecomastia.
National Cancer Institute.Breast anatomy.
Canadian Cancer Society.The breasts.
Zucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surg. 2016;5(1):32-36.
National Organization for Rare Disorders.Pagets disease of the breast.
American Pregnancy Association.Breast changes during early pregnancy.
Alex A, Bhandary E, McGuire KP.Anatomy and physiology of the breast during pregnancy and lactation.Adv Exp Med Biol. 2020;1252:3-7. doi:10.1007/978-3-030-41596-9_1
National Library of Medicine.Subareolar abcess.
Kantha SS.Montgomery glands in the areolar region: A clinical overview.Int Med J. 2023;30(3):128-31.
Susan G. Komen.Breast anatomy.
American Cancer Society.Invasive breast cancer.
American Cancer Society.Ductal carcinoma in situ (DCIS).
Centers for Disease Control and Prevention.What does it mean to have dense breasts?
University of Michigan Health.Mastitis while breastfeeding.
National Library of Medicine.Female reproductive system.
Sophia L, Singh D, Xalxo N, et al.Upper limb arterial pattern: Clinical correlation and embryological perspective.J Vasc Bras. 2021;20:e20210008. doi:10.1590/1677-5449.210008
Columbia University Department of Surgery.Guide to breast cancer.
American Cancer Society.Inflammatory breast cancer.
Zhang S, Zhang D, Yi S, et al.The relationship of lymphatic vessel density, lymphovascular invasion, and lymph node metastasis in breast cancer: A systematic review and meta-analysis.Oncotarget. 2017;8(2):2863-2873. doi:10.18632/oncotarget.13752
American Academy of Family Physicians.Breastfeeding: Tips to get you off to a good start.
American Cancer Society.Post-mastectomy pain syndrome.
Stonybrook University Hospital.General breast health.
Johns Hopkins Medicine.Mastalgia.
Johns Hopkins Medicine.Folliculitis, boils, and carbuncles.
Johns Hopkins Medicine.Breast pain (mastalgia).
Johns Hopkins Medicine.Gynecomastia.
Zucca-Matthes G, Urban C, Vallejo A.Anatomy of the nipple and breast ducts.Gland Surgery. 2016;5(1):32-36.
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