Understanding Breast Health: Anatomy and Physiology

Nurturing Wellness, Resilience, and Vitality for Healthy Post-Cancer, Post-Pregnancy, and Post-Surgery Breasts

Understanding the anatomy and physiology of the breasts is a critical first step to supporting breast health. Becoming informed about the miraculous inner workings of the breasts contributes to understanding the path of:

  • Breast cancer risk and prevention 
  • A breast cancer diagnosis
  • Healthy breastfeeding and breast care
  • Breast removal after breast cancer 
  • Implanting and explanting

Breast Health: Anatomy and Physiology

There are 15-20 lobes in the breast, arranged like the petals of a flower. Within each lobe are many smaller sections of 20-40 lobules, configured like clusters of grapes. And at the ends of the lobules are dozens of tiny bulbs that can produce milk. Lobes, lobules, and bulbs are connected to each other by tiny tubes called ducts. These are all considered glandular tissue. 

In addition to the lobes, lobules, bulbs, and ducts, there is fibrous, or supportive connective tissue–the same kind of tissue that forms scars and ligaments. 

Fatty tissue fills the spaces between the glandular and fibrous tissue (commonly called fibroglandular tissue), more or less determining breast size. 

There is also circulation in the breast tissue via both blood and lymphatic vessels. The lymphatic vessels lead to lymph nodes in the armpit, above the collar bones at the base of the neck, and in the chest between the ribs.

There isn’t any muscle in the breasts, but the important pectoralis, serratus anterior, and abdominal oblique muscles lie against the chest wall, beneath the breasts, giving them support. In addition, ligaments span from the skin to the chest wall, further supporting the breasts.

Anatomy and Physiology in Summary

To summarize, the breasts have an internal daisy flower arrangement, with each petal a lobe. Within the lobes or petals are clusters of grape-like lobules with tiny milk-producing bulbs at their ends. The “grapes” are connected on stem-like tubes called ducts that carry milk to the nipple, and supportive fibrous connective tissue forms an infrastructure holding together this dynamic network of fibroglandular tissue. The grapevines through which nourishment enters and waste products leave are the vascular and lymphatic vessels. Fatty tissue surrounds all of this, much like the protective netting in a vineyard. 

Anatomy and Physiology of Breast Cancer

Breast cancer most commonly forms in the ducts and lobules of the breasts. How the different screening technologies detect lobular and ductal cancer makes more sense with an understanding of breast anatomy.

When most of the tissue seen on a mammogram is fibrous or glandular tissue rather than fat, that’s called dense breasts. Because denser tissue is white on mammograms (low-dose x-ray screenings), and cancer cells also show up as white, it can be difficult to see disease in people with dense breast tissue

Digital breast tomosynthesis, or 3-D mammography, provides a deeper look into breast tissue by capturing images from many more angles. 

Contrast-enhanced digital mammography, or CEDM, combines mammography with a contrast dye that cancer cells will absorb more readily than breast tissue, offering a stronger image. Ultrasound (sound-wave imagery that relies greatly on the expertise of the technician for its increased effectiveness) or MRI (a combination of radio waves, a powerful magnet, and fluid injection for improved visibility) may then be used for even more comprehensive detection. 

Breast cancers are typically invasive or non-invasive, meaning that the cancer has broken through the ducts and lobules to invade the surrounding tissue, or the cancer cells are only growing within the ducts and lobules. Approximately 65-85% of all invasive breast cancers are ductal in origin.

Anatomy and Physiology of Pregnant Breasts

During pregnancy the breasts undergo miraculous anatomical and physiologic changes. In fact, adolescence only begins the process of breast development; the process is completed during pregnancy.

The fatty tissue and the lobes that have the ducts that drain into the nipple/areolar complex (the petals, grapes, and stems) are present in adolescence. Pregnancy triggers increased estrogen in the first trimester, with an expansion and elongation of the ductal system (the grape stems) into the fatty tissue and a reduction of that fatty tissue. The estrogen stimulates the pituitary gland to elevate prolactin levels, and by the 20th week of pregnancy, mammary glands respond to the increased prolactin by producing colostrum.

In the third trimester and postpartum, estrogen and progesterone levels decrease and colostrum production shifts to breast milk production, allowing the let-down necessary for breastfeeding. 

Most pregnancies cause the areola to darken, the breast to increase in size, and the Montgomery glands in the areola to become more prominent. 

Post-lactational involution (the mammary glands remodeling as tissues begin to resemble pre-pregnancy state) occurs when milk production ends and prolactin levels decline.

The rapidly changing ratios of hormones circulating, as well as increased blood and lymph flow to the breasts during pregnancy, explain the common symptoms of breast discomfort, mastitis, heaviness, lymph and milk duct blockages. These can gently and effectively be loosened to promote free milk flow, lymphatic drainage, and mom-and-baby wellness with lymphatic drainage therapy.

Anatomy and Physiology of Post-Surgical Breasts: Implant and Explant

Breast implant surgery can be part of cancer treatment or a personal choice for a variety of reasons. Implants can replace part or all of a breast in the case of breast cancer, or can be added to augment current breast size and/or shape. Explant is the removal of an implant.

In cases where the complete breast is removed, total mastectomy, no breast tissue is typically left behind. A person can choose to “go flat,” create a breast from their own tissue (autologous flaps), or place an implant (silicone or saline).

Total mastectomy and Going Flat

In simple, radical, or total mastectomy and going flat, the complete breast is removed, typically the muscles remain, and the pectoralis major fascia is removed with all the mammary tissue. In modified radical mastectomy axillary lymph nodes are also removed.


Implants for breast augmentation are typically placed either behind the breast tissue or under the chest muscles, through a variety of possible incisions: at the natural fold underneath the breast, through the armpit, or around the edge of the areola. A saline implant can be placed through a cut near the belly button, using an endoscope to move the implant to the breast/chest and then filling it with saline once it is positioned.


When an implant is removed the process is called explanting. This can be done after breast augmentation or reconstruction for any number of personal and/or health-related reasons. This procedure, regardless of the personal why, is often an extremely emotional process that requires considerable support and self-love as the trauma, and the healing, can be profound.

When an implant is removed after augmentation, the breast remains intact, and some skin and tissue sagging likely results, in addition to scar tissue from the explant incision. It can be highly beneficial to receive lymphatic drainage therapy, scar massage, and other loving bodywork to create new neural connections, assist with skin and scar health, and get gently reacquainted with these smaller sisters.

When an implant is removed, loving bodywork is a must.

When an implant is removed after reconstructive surgery for cancer treatment, loving bodywork is likely a must. Lymphatic drainage therapy, cold laser, and scar massage can address the healing tissues as well as the emotional re-trauma in addition to the physical re-trauma common for cancer survivors and thrivers.

Disclaimer – This blog is for general information purposes only. Furthermore, the information contained in this blog is not a substitute for medical advice. Always consult your licensed healthcare professional for advice on your specific condition.

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