Breast anatomy and development — bosom up!


Breast anatomy and development — bosom up!

In today’s episode, we’re discussing an organ that comes in two. In addition to feeding your offspring, with proper stimulation, it can also affect your sex life. Our advice? Keep abreast of your breasts!

Dominika Olchowik

Published: 15.02.2022 11 minreading time

breast anatomy cover

Illustration: Jarek Danilenko

Breast anatomy

Breasts (in medical terms known as mammary glands or simply breast tissue) are the largest cutaneous glands in humans. They’re located on the chest in the space between the 2nd or 3rd and the 6th or 7th rib.

Breasts comprise:

  • Glandular tissue that is made mainly of elements called lobules, which are surrounded by clusters of alveoli. To carry milk out of the breasts through the mammary gland, they are equipped with lactiferous ducts (or milk ducts).

  • Adipose tissue and connective tissue, which both surround and protect glandular breast tissue and give the breasts their shape.

The lymph nodes that surround the breasts are the following:

  • Supra- and subclavicular lymph nodes

  • Axillary lymph nodes

  • Internal mammary lymph nodes (retrosternal).

Nipples are places where milk gets out of the breast. They are surrounded by a dark area of skin called areola, which has numerous sebaceous and sweat glands. The mammary gland is densely innervated, making the female breasts sensitive to touch and stimulation, and consequently one of the erogenous zones of the body.

Breast growth stages

The process during which the breasts develop and grow and when their production and offspring-feeding functions crystallise is called mammogenesis.

The breasts begin to develop already in the foetal period — the process starts in the fourth week and is triggered genetically and by the sex hormones of the mother. Around the fifth week of gestation, a mammary ridge (or milk line) appears, which then grows until week 12, creating secondary mammary buds and lobules. Ligaments, nerves, arteries, veins, and lymph vessels develop throughout the entire pregnancy.

After birth, when the mother’s hormones cease to affect the breasts, they remain ‘dormant’ until thelarche — the beginning of breast development in puberty.

Puberty is a time of the most significant breast growth. This is when the ovaries start to produce sex hormones on their own — oestrogens are essential in breast development and vital for the stimulation of their growth and the deposition of fatty tissue. Another sex hormone — progesterone — is indirectly responsible for the development of lobular alveoli that facilitate lactation (milk secretion).

Tanner scale, a.k.a. sexual maturity rating

The Tanner scale makes it possible to determine the level of sexual development of children and young people. Evaluation is performed on the basis of morphological qualities (such as pubic hair, height, or breast development).

The scale has 5 stages:

  • In stage I (prepubertal), the mammary glands slowly start to manifest.

  • Stage II is when the breast buds begin to form and the areola widens. Pubic hair is scarce and soft.

  • In stage III, as a result of the continued development of fatty tissue, the contours of the breast become more elevated; the areola is further extended. Pubic hair continues to grow and becomes darker and curly.

  • During stage IV, the areola and nipple create a secondary mound on the breast.

  • The final stage V is when the breasts reach their adult size (are fully developed) to which the nipples adjust their shape to.

The exact age of occurrence of particular stages is an individual matter. Obviously, there are some accepted frameworks; however, whether the process runs its course in a healthy and natural rhythm should be left to a specialist to determine. The Tanner scale is a good reference point — it has been used as the gold standard in medicine for many years.

In the subsequent years of life, after puberty, the breasts can change due to, for instance, pregnancy. Old age starts roughly at 55 years, and this is the time when the breasts start to lose their firmness and elasticity and begin to sag.

Breast size depends on…

genetics. This is truly one of the factors that influence the shape and size of the breasts. It has not been confirmed, though, that the pattern concerns the genetic material of the mother. We receive our bodily characteristics from both our parents, and the final ‘effect’ also depends on many different elements.

Breast development is caused by female sex hormones — thanks to those the fatty tissue grows. All fluctuations in this matter can impede breast growth altogether. Body weight is also important — since breasts are filled with adipose tissue, its general increase might cause the breasts to enlarge. But it doesn’t necessarily mean that an extra donut will end up filling up your cup :) It all circles back to the hormones. Depending on their levels, fat tends to accumulate in various places of the body, for instance, in its lower parts.

Normal breast development — frequently asked questions

Does it hurt when they grow?

Breast pain can occur on multiple occasions — for many people it’s a recurrent ailment related to hormonal processes and endocrine imbalance that accompany PMS, that is, the premenstrual syndrome.

As a result of breast development, under the influence of sex hormones, the breast tissue transforms and skin stretches, which might cause pain and discomfort. Breasts start to grow before the first menstrual cycle, which is why the ache might be a prelude to the menarche. In addition, many young people (between 9 and 12 years old) complain about a painful (and very alarming both for the children and their parents) lump under the nipple. There is nothing to worry about, though, as it is a completely normal symptom that marks the beginning of puberty.

My breasts are asymmetrical — is it bad?

A slight disproportion in the size of your bosom is quite common and shouldn’t worry you. Ideally symmetrical are only those of Barbie dolls and characters in the Sims ;) If the asymmetry is very noticeable and raises a red flag, it’s worth checking it with your doctor. Asymmetry can result from excess fatty tissue in one breast; however, sometimes we’re dealing with more serious afflictions.

The issue may also be purely aesthetic in nature — if you’re not happy with the shape of your breasts, there is always the option of plastic surgery. It offers a number of possibilities to augment the shape of your bosom (using an implant, the breast feather lifting method, or fat transfer).

How will my breasts change after I get pregnant?

Several factors can have an impact on the change in breast shape: the menstrual cycle, menopause, body weight fluctuations…

You might feel the variations already in the early stages of pregnancy — your breasts start to enlarge, they may be more tender and sensitive to touch. Furthermore, during the second trimester, your nipples and the areola gradually darken.

Many pregnant people complain of itching and notice stretch marks surrounding their breasts. These are the results of the skin stretching, as well as the changes that occur in the connective tissue.

Relief for irritated breast skin

To alleviate various skin problems, you can use our SOS cream — gently pat it on places that need a bit of extra care.

I sense a lump in my breast — is it cancer?

Luckily, not all lumps and breast changes are malignant cancerous tumours. In most cases, they are benign and include, for example, fibroadenomas — otherwise known as breast mice. There are several different types, and they usually occur plurally. The causes of fibroadenoma are not exactly determined. It also happens that the doctor does not qualify the change to be removed — if it doesn’t raise serious concerns, regular check-ups suffice.

Another benign change is a breast cyst. The majority of cases are asymptomatic, although they might sometimes cause pain or tenderness of the breasts (especially the galactocele, which might occur during lactation in breastfeeding people as a result of blocking one of the milk ducts).

All such changes should be properly diagnosed — it is the doctor who decides on further treatment and a possible removal of a lump (moreover, they can perform a biopsy to assess whether the change can evolve into a malignant form).

How to take care of your breasts?

We should start taking care of our breasts, similarly as we do with our entire bodies and minds, from our earliest years :) Conscious and mindful care and making sure to moisturise the skin, using sunscreen creams in particular — these are the basics. But what should we also keep in mind?

  • Choose proper underwear — many people struggle with choosing a well-fitting bra (I have flashbacks from some tv shows where women underwent metamorphoses, and one of the key moments of the programme was to buy a new bra; next to NONE of the ones the women had worn was good — they were always a couple of sizes too small). Why does it matter? A bra that squeezes your breasts is not only hellishly uncomfortable to wear, but poses some serious threats — it can mess with the flow of your blood, pinch nerves, and, when worn non-stop, might lead to breast deformation. Too loose a bra but with tight cups might burden the spine.

  • When the night comes and you finally hit the well-deserved hay, leave your well-fitted and comfortable underwear somewhere on the shelf ;) It’s important to cut your breasts some slack at night, so that the skin can ‘breathe’ a little.

  • Breast skin is very sensitive, so don’t tan too much — remember about the sunscreen!

Your body changes constantly — it’s perfectly normal. And beautiful! You can reward it with some mindful care of all its bits. Your KAYA intimate wash was created just so that you can take care of your private parts gently and safely.

However, the most important point on your to-do list should be tests. What tests ask you?

Self-examination, a.k.a. control your bosom

Breast self-examination relies on visual and palpatory (tactile) assessment. The process might be divided into 5 steps:

  • Stand in front of a mirror in an upright position and rest your hands on your hips. Take a close look at the shape, colour, and size of your breasts — do you notice any unusual changes?

  • Remain standing in front of the mirror and raise your arms. Make sure your nipples have not sunken and their colour doesn’t raise a red flag, and the breasts themselves don’t hurt or show signs of irritation.

  • Another important step is to check whether the nipples don’t secrete any worrying discharge. It’s super important, so take an extra close look!

  • Lie down in a comfortable position. Use your right arm to examine your left breast and your left arm to check your right breast. In semicircular motion, apply gentle pressure on the respective breast with your straightened fingers.

  • You can go through the last step either standing up or sitting down, even in the shower :) Take an extra moment to repeat the motion from the previous step. Place one arm behind your head while using the other to examine your breast. Pay attention to the axillary lymph nodes!

When to perform self-checks?

It’s recommended to perform breast self-examination once a month. The best time to do this is between day 7 and 10 after the onset of menstrual bleeding. During period, under the influence of changes in hormonal balance, the breasts can hurt and enlarge, which is why it’s best to do a self-check when the menstrual dust settles and the sex hormones return to their stable levels.

Breast cancer — forewarned is forearmed!

Breast cancer is one of the most common malignant cancers in women. People between 45 and 69 years of age are those who suffer from it most frequently.

In the case of breast cancer, early diagnosis increases the chances of even a full recovery. Mammography and ultrasound scans are two basic tests used to detect disturbing changes in the breast anatomy.

Breast carcinoma can also be a dangerous condition for young people; it occurs most frequently in pregnant people. It’s recommended to perform preventive ultrasound scans once a year. Depending on the structure of your breasts or the possible visible breast changes, a mammography might be necessary.

People with a family history of breast or ovarian carcinomas can carry BRCA1 or BRCA2 genetic mutations — if so, it’s crucial to run additional tests to detect those.

The risks of getting breast cancer increase with age, regardless of sex — about 80% of cases pertain to people over 50. In elderly people, the lobular structure of the breast is more fatty; therefore, they should make sure to have a mammography done every year.

What is the difference between mammography and ultrasound scan?

The choice between the two tests depends chiefly on the age, which influences the changes in the breast anatomy.

Mammography uses X-rays, which are excellent for the analysis of adipose tissue. Glandular tissue, on the other hand, might be a bit unintelligible in an X-ray picture. This is why mammography is recommended in patients after 40, when the fatty tissue starts to take over. The image obtained during an ultrasound scan develops thanks to, as the name suggests, ultrasounds that make it possible to achieve contrast between the glandular tissue and possible changes thereto.

When to visit a doctor?

  • The presumptive lump in your breast (or the axillary fossa) grows or doesn’t change during the normal menstrual cycle — it’s firm and doesn’t move.

  • You’ve noticed discharge secreting from the nipple (unrelated to lactation).

  • The skin surrounding your breast is irritated, red, wrinkled (the so-called peau d’orange, literally skin of an orange), or stretched.

  • You suffer from nipple pain.

  • Your nipples have sunken.

Remember: every troubling change related to your breasts should be diagnosed — better to be safe than sorry. It’s especially important to make an appointment if:

Beautiful breasts are ALL breasts!

And most importantly — healthy ones!

Large, small, rounded, bell-shaped or teardrop-shaped, asymmetrical… There’s no universal canon of perfect, beautiful breasts (although some daredevils have tried to conjure up a formula for the perfect bosom — we totally don’t get it).

Conscious selfcare, preventive check-ups — uh-huh, that is sexy! Battling your complexes is not always a fair or easy fight. Accepting and loving your body exactly the way it is is one thing. However, if breast augmentation (or reduction) or other plastic intervention is to make you feel better about yourself and pump some spirit into you — go for it! The covers that crow in bold about yet another celebrity who has their bust size doubled are getting boring. Where’s the news… ;)

  1. L. Burgess, Do breasts hurt when they grow?, med. rev. J. Brito, [dostęp z dn. 22.07.2021].

  2. W. Chan, B. Mathur, D. Slade-Sharman, V. Ramakrishnan, Developmental Breast Asymmetry, „The Breast Journal” 2019, vol. 17, i. 4, p. 391-398.

  3. R.A. Jesinger, Breast Anatomy for the Interventionalist, „Techniques in Vascular and Interventional Radiology” 2014, vol. 17, i. 1, p. 3-9.

  4. Normal Breast Development and Changes, [dostęp z dn. 22.07.2021].

  5. S. Pandya, R.G. Moore, Breast Development and Anatomy, „Clinical Obstetrics and Gynecology” 2011, vol. 54, i. 1, p. 91-95.


Dominika Olchowik
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