The Parts of the Outer Breast

Anatomy From Nipples to Areola to Montgomery Glands

If you're reading descriptions about breast concerns, you may catch yourself trying to recall anatomy lectures that occurred many decades ago. What are the parts of the outer breast including the nipple, areola, Montgomery glands, and other structures? What is the purpose of these different parts and what medical conditions may affect them?

Female breast anatomy, illustration

Anatomy of the Outer Breast

When it comes to breast anatomy, your nipple is the crowning touch. Your nipple is at the business end of the breast milk system, the first place a newborn baby will seek out. It is very sensitive to touch and temperature and may be the place your partner likes to target. What's inside your nipple and areola? Let's take a look at the inner workings of your outermost breast anatomy.

Milk Ducts

Milk ducts are small tubes that transport milk from the milk glands (the lobules in the breast) out the tip of the nipple. Ducts are lined with myoepithelial cells. 

Breast milk is released from holes at your nipple's surface called milk duct orifices. You will have 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 (valves) that close to prevent leakage when you are not breastfeeding.

The ducts just below your areola widen before they enter your nipple. This wide, sac-like area is called an ampulla. Sometimes the ampullae are called frontal ducts.

Conditions That Affect Breast Ducts

Mastitis is a condition in which a breast duct becomes plugged. It can be very uncomfortable, but usually responds well to heat and antibiotics.

Most types of breast cancer start to develop in the ducts as well. Ductal carcinoma in situ and invasive ductal carcinoma originate in the milk ducts. A ductogram or the Halo test may be used to examine breast fluid or ductal cells.


Surrounding the nipple is your areola, an area of skin that is darker than the rest of your breast skin. Small bumps on the areola may be either Montgomery's glands or hair follicles. You can usually tell the difference because hairs emerge from the hair follicles.

Your areola may be small or large, round or oval. During pregnancy, areolas may grow in diameter, and your areala may remain larger (and sometimes darker) after pregnancy.

Condtions That Affect the Areola

If you notice a change in your areola skin, such as dimples, puckers, or a rash, check with your doctor. These might be harmless, but could also be symptoms of Paget's Disease, an uncommon type of breast cancer which begins in the nipples with a scaly, red rash. In the early stages, Paget's disease can look like a normal rash related to irritation from your bra. If you have a rash which is not resolving, make sure to talk to your doctor.

Symptoms of tenderness or a hard lump beneath the areola may also be a symptoms of asubareolar abscess, an infection that the body walls off, and may need to be drained.

Montgomery Glands

Montgomery glands are special glands that lie just below the surface of your areola and may be seen as small bumps in the skin. Also called areolar glands, these provide lubrication during breastfeeding.

Conditions That Affect Montgomery Glands

Montgomery glands may become blocked, like pimples, and swell. A cyst may develop beneath a blocked gland, but this does not increase your risk for breast cancer. It can, however, be quite uncomfortable.

Hair Follicles

Hair follicles are present on the outer breast, especially on the surface of your areola. Due to these follicles, it is not unusual to have a few hairs growing on the surface of your areola or breast skin. If these are bothersome, carefully trim them. Pulling them out with tweezers can be painful and may open the way to infections.

Sulcus (of the Breast)

At the intersection of the areola and the rising edge of the nipple is a fold called the sulcus. It may be a smooth curve of skin, or it may look like a wrinkle. Inverted nipples may hide within the sulcus while retracted nipples may pull in at the sulcus line.

Blood Circulation of the Breast

Your nipples and areolas are connected to your blood supply by your axillary arteries. If you are having nipple-sparing breast surgery, the blood supply must be preserved to keep these tissues alive. With a nipple sparing mastectomy the body side of the nipple is scraped to remove as many remaining breast cells as possible. This can, however, disrupt the tiny blood vessels leading to loss of your nipple later on.

Muscles and Ligaments of the Breast

Nipples are held erect by small, smooth muscles that respond to signals from your autonomic nervous system (the "unconscious" nervous system over which you do not have voluntary control). Nipple erection can be caused by cold temperature or stimulation. Even though nipples can respond to sensual caresses, they are not considered sex organs.

Cooper's Ligaments

Cooper's Ligaments form a hammock for your breast tissue to keep its shape. These ligaments run from tissue in your collarbone and chest wall throughout the breast and up to the areola skin. With age, these ligaments often stretch, leading to the popular slang term "Coops droop."

Summary of the Anatomy of the Outer Breast

As noted above, there are a number of different structures located in the outer breast, many of which can become involved in breast conditions. It's important to let your doctor know of any changes you note in or beneath your nipple and areola. Most changes are a nuisance and not cancer, but sometimes cancer can present in uncommon ways.

You may also be interested in learning about the anatomy of the inner breast or how the breast changes with breastfeeding.

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