The breasts and lymphatic system

This page tells you about the structure of the breasts and about the lymphatic glands. There is information about

A quick guide to what's on this page
The breasts
Breast size and density
Lymph glands and the lymphatic system
More information about breast cancer

The breasts and lymphatic system

The breasts are made up of fat, connective tissue, and gland tissue divided into lobes. A network of ducts spreads from the lobes towards the nipple.

Breast size and density

The breasts are not usually the same size as each other. They may also feel different at different times of the month – for example, just before a period they can feel lumpy. Younger women have more glandular tissue in their breasts, which makes them dense. Once a woman is past her menopause, the glandular tissue is gradually replaced by fat, which is less dense.

The lymph nodes

An area of breast tissue leads into the armpit (axilla). The armpits have many lymph glands, also known as lymph nodes. They are part of the lymphatic system. The lymphatic system is made up of a network of lymph glands, connected throughout the body by tiny tubes called lymph vessels. Lymph is a yellow fluid that flows through the lymphatic system and eventually drains into veins. This system helps to get rid of waste products from the body.

Lymph glands are important in cancer care because any cancer cells that have broken away from a tumour can be carried by the lymph to the nearest lymph glands. If you have cancer, but no cancer cells in any of your lymph glands, your cancer is less likely to have spread.

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The breasts are made up of

Fat
Connective tissue
Gland tissue divided into lobes

A network of ducts spreads from the lobes towards the nipple.

The breasts are not usually the same size as each other. They may also feel different at different times of the month – for example, just before a period they can feel lumpy.

The density of the breasts changes as women get older. Younger women have more glandular tissue in their breasts, which makes them dense. Once a woman is past her menopause, the glandular tissue is gradually replaced by fat, which is less dense. During breast screening it is harder to read a mammogram if the breast tissue is dense. So mammograms are not as reliable for young women.

Specialists have found that older women who take hormone replacement therapy (HRT) have denser breasts than would be expected for their age. This is related to the HRT. It isn't a problem in itself, but it may make mammograms less accurate for these women.

Get to know your breasts over time. Learn what natural changes take place during your periods and at other times. Look at your breasts when you change your clothes. Or feel your breasts – for instance when you take a bath. Look for changes that seem unusual for you. If you find an unusual change, see your doctor or nurse practitioner as soon as you can.

An area of breast tissue, under the skin, leads into the armpit (axilla). The armpits have many lymph glands, also known as lymph nodes. There is also a chain of lymph nodes that runs up the centre of your chest, by your breast bone. This is called the internal mammary chain. The diagram shows the network of lymph glands around the breast.

Diagram showing the network of lymph nodes in and around the breast

The lymph glands are part of the natural drainage system of the body called the lymphatic system. The lymphatic system is made up of a network of lymph glands, connected throughout the body by tiny tubes (vessels) called lymph vessels. Lymph is a yellow fluid that flows through the lymphatic system and eventually drains into veins. This system helps to get rid of waste products from the body.

Tissue fluid bathes the body's cells, drains into the lymphatic system and then circulates again. Lymph glands are important in cancer care because any cancer cells that have broken away from a tumour can be carried by the tissue fluid to the nearest lymph glands. So doctors always examine the lymph glands. If you have cancer, but no cancer cells in any of the nearby lymph glands, your cancer is less likely to have spread.

There are many books and booklets about breast cancer, some of which are free. You can find details on our breast cancer reading list.

You can contact the Cancer Research UK nurses. You can also find details of other breast cancer support organisations in our list of breast cancer organisations and websites. Many of them have information and free leaflets about the breasts and how to care for them. Breast Cancer Care has a leaflet about breast awareness called Your breasts, your health. You can ask them to send it to you.