Your anatomy

🍒 To learn how to pump well, you need to learn more about what your breasts are going through. Hint: a lot.

First, we’re going to break down your anatomy in detail, how your breasts make milk, and what happens to your breast (and in fact your whole body) when a baby feeds or you pump.


Your breast

Let’s start with the anatomy of a breast.

[insert diagram - surface]

On the surface, the visible part of the breast is the same for most people: the areola and the nipple. But for the female[1] breast, the anatomy is different, all created through marvellous evolution so that we can produce milk and breastfeed.

So here’s what a breast looks like inside.

[insert diagram - inside]

Your breast has three types of tissues:

  1. Glandular tissue — Responsible for producing the milk
  2. Fatty tissue — Determines the size of each breast
  3. Connective tissue — A fibrotic tissue responsible for holding the glandular and fatty tissue in place

Glandular tissue is involved in milk production and is made up of many glands called lobules.

The lobules look like a bunch of grapes and each lobule gland has tiny sacs called alveoli that produce and hold milk. Similar to the stem that holds grapes together, lobules are connected by terminal ducts that help transport the milk from the lobule out to the nipple through the milk ducts. Read more on exactly how milk gets made and pushed through your breast here.

Your areola and nipple

Areolas are typically round and darker than the rest of the breast. Areolae have their own set of glands called Montgomery glands, which secrete oil to help lubricate the nipple and skin to prevent chafing while breastfeeding.

Why are they called Montgomery glands? After an Irish obstetrician who studied changes in the nipple over pregnancy, in the early 1800s. He got some things right, and some things less so - read more about these here.

The nipple refers to the smaller section near the middle of the areola that typically sticks out when stimulated. There are approximately nine milk ducts in each nipple that are used to get the milk out of the breasts. Read more on how you make milk here.

Nipples and areolae can vary in shape and size and that variation is normal. We know from our own surveys at Milkdrop that nipples alone can range from 5 mm to 40 mm. They can also be long, round, flat or inverted, and anything in between. On top of this, your two nipples may be different from one another. They’re sisters, not twins!

[insert bank of nipples - different sizes & shapes]

Why we don’t know that much about the size and shape of lactating nipples

While there is a huge body of research on the anatomy of the nipple, it’s not quite in the way you might think.

We know surprisingly (and embarrassingly) little about the size and shape of the female nipple. This means it’s hard to design products like breast pumps for them.

Most of the nipple-y research seems to focus on two areas.

Plastic and reconstructive surgery

Much of this research is about how to create the “ideal” nipple for attractiveness. Surgeons need guidance on how and where to create and place the nipple for augmentation or reconstructive surgery, but still. Ugh.

Surely the most “attractive” nipple is the one you have?

Not so. There are other characteristics typically determined by asking study participants to rank ‘attractiveness’ based on models or photographs of people’s breasts. These include breast width to upper buttock width ratio, nipple direction, breast width to shoulder width ratio and breast projection (i.e. sagginess).

Some papers do talk about the patient’s own feeling of attractiveness, rather than someone else’s view of her attractiveness. It still feels odd to have created an environment where a woman feels her attractiveness is dependent on her nipple placement and shape, and then funded more research into defining that attractiveness better.

Identifying nipples in images

Another investment area in understanding nipple shape is for developing algorithms that accurately and efficiently identify nipples within images. Ostensibly to identify pornography (fair enough), these algorithms are also behind defining ‘sensitive’ content on social media platforms, which often can simply be a …. lactating nipple. This area of research isn’t quite as frustrating as the first one, because the algorithms are also used in the software behind mammograms and other health technology.

To show you the scale of this issue, we have counted x studies specifically on the size, shape and function of the lactating nipple.

We are not intending to be rude to researchers, surgeons or people who are beneficially affected by the research and development we describe above. We would just like to see an equal (if not more) level of effort and funding to understanding the lactating nipple and supporting people to feed breast milk to their babies.

How your breast changes

You may have noticed your breasts change during pregnancy. Not only do breasts typically get bigger, but the areolae and nipples also undergo changes during pregnancy. The visible changes to the areola and nipple are caused by hormones and promote breastfeeding.

The areola and nipples get visibly darker and larger during pregnancy for most people, which we think helps the baby see the contrast in color between the areola and the rest of the breast. The Montgomery glands on the areola may also be more noticeable during pregnancy, although not always. In later pregnancy, you may even notice a sticky secretion from these glands, or perhaps you might see that water beads more when it’s on your breast. This is the secretion from the Montgomery glands as your breast prepares for lactation.

Here’s a list of the things that change during each trimester:

  • First trimester: Your system of milk ducts grows and branches out into your fatty tissue (thanks to more estrogen running through your body)
  • Second trimester: Your mammary glads are ready to produce milk
  • Third trimester:

  • Nipple colours – pale, dark, red
  • How nipples change through pregnancy, breastfeeding or pumping
  • Which nipples are “best” for breastfeeding
  • Which nipples are “best for pumping
  • elastic nipples
  • breast anatomy – nipple
  • breast anatomy – nipples