Female Breast Anatomy

Female breast anatomy ~ lactating breasts

This page focuses on the anatomy of the breast, if you want more detail on the lactation process and how it works you can read our page on breast milk production.

Cross section of a lactating breast

Breast milk travels from the cluster of alveoli ( the alveolus ), also called…milk producing cells, glandular tissue, mammary glands or milk glands then into the milk ducts “lactiferous ducts” and through the sinuses then out of the nipple openings.

Oxytocin is the hormone released that is responsible for the ejection of milk. Prolactin is the hormone responsible for the milk production. The breast milk is continuously made and collects inside the milk sinuses.

The breast normally has about 15 to 20 of these structures including the sinus, ducts and the alveoli. There is fat also that surrounds these.

Female breast anatomy ~ Latching on

Baby needs to take in the entire nipple and a large part of the areola in order for a good latch and good milk transfer. The nipple should touch the soft palate in baby’s mouth.

With a good latch like this one it is almost impossible for mom to have sore or broken nipples as baby’s teeth are far away from the nipple and the nipple is protected by the soft palate.

This latch will also ensure that baby is stimulating the areola (dark part around the nipple) which triggers the oxytocin hormone…therefore getting milk flowing better.

A mom’s nipple will elongate to about twice it's normal length when drawn into baby’s mouth

Read more about getting a good latch on here

Female breast anatomy ~ The alveoli

The alveoli (milk producing cells)

These are made up of milk gland cells around the end of a milk duct. The gland cells produce milk and with the help of myoepithelial cells the milk is ejected into the milk duct which then travels down into the milk sinus and is kept there until baby breastfeeds.

Milk is produced during and between feedings. The milk that collects in the milk sinuses is called foremilk, the milk further back in the alveoli and milk ducts is called hindmilk, which is richer in fat content as most of the fat globules have collected there as the milk passed through. This is why it is so important that mom allows baby to breastfeed on one breast until it seems empty so that baby can receive the substantial hind milk too.

Read more on hind milk foremilk imbalance.

Female breast anatomy ~ Nipples

Nipples

All women have different nipple sizes, but some women find it more difficult to breastfeed if they have flat or inverted nipples.

How to know if your nipples are flat or inverted

Nipples have several openings through with the milk will flow.

Female breast anatomy ~ Lactogenesis and mammogenesis

A mom that might have struggled with a low milk supply with her first baby will have a better milk supply with her second child as breast tissue has increased and matured through a process called lactogenesis ( enabling milk secretion ) and mammogenesis (maturation of glands and ducts) This is especially true if the mother stuck it out with breastfeeding for at least two months the first time around.

Remember that the size of your breasts have absolutely nothing to do with the amount of breast milk produced. Most of the time moms with very large breasts have the same amount of breast tissue as moms with very small breasts.

Changes include:

- With every pregnancy your breasts will increase in size

because of the increase in lobules and alveoli which are needed for breast milk production.

- Breast sinuses are developed (which where non existent before pregnancy)

- Veins may become darker and more visible through the skin on the breasts

- The Montgomery glands (small nodule like structures on the areola) will start to produce an oily like substance that will lubricate the skin and also keep your breasts bacteria free.

- The areolas may become darker and larger

- Nipples might become larger

Blocked milk duct picture on the right...

Read more on how to deal with blocked milk ducts

Read more on how to deal with a nipple blister “bleb”

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