The Parts of the Outer Breast

Outer Breast Anatomy From Nipples to Areola to Montgomery Glands

An illustration of a female breast.
What are the parts of the outer breast including the nipple and Montgomery glands?. BSIP/UIG/Getty Images

What are the parts of the outer breast including the nipple, areola, Montgomery glands, and other structures? What medical conditions may affect these different structures?

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 (lobules) out the tip of the nipple. Ducts are lined with myoepithelial cells. 

Mastitis is a condition in which a breast duct becomes plugged. Most types of breast cancer start to develop in the ducts. 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.

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.


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.

Your areola may be small or large, round or oval.

During pregnancy, areolas may grow in diameter. 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 uncommon type of breast cancer which begins in the nipples with a scaly, red rash.

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. 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.

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.

Muscles and Ligaments of the Breast

Nipples are held erect by small, smooth muscles that respond to signals from your autonomic nervous system. 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.

Summary of the Anatomy of the Outer Breast

As noted above, there are a number of different structures located in the out breast, many of which can become involved in breast conditions. You may also be interested in learning about the anatomy of the inner breast or how the breast changes with breastfeeding.


Javed, A., and A. Lteif. Development of the Human Breast. Seminars in Plastic Surgery. 2013. 27(1):5-12.

Love, Susan M., Elizabeth Love, and Karen Lindsey. Dr. Susan Love's breast book. Boston, MA: Da Capo Lifelong, 2015. Print.

Zucca-Matthes, G., Urban, C., and A. Vallejo. Anatomy of the Nipple and Breast Ducts. Gland Surgery. 2016. 5(1):32-36.