Hello everyone! It's Megan from Kenhub here, and welcome to our tutorial on the female breast structure. During this tutorial, we'll look at the structures that make up the female breast as well as some related and surrounding structures that you can see in this image here. So in this illustration, we can see a view of the breast from the side rather than an anterior view and we can see structures such as the nipple, the areola, the lactiferous ducts along with the mammary glands and the surrounding adipose tissue. We can also see the vascular supply and the underlying muscles such as pectoralis major and the intercostal muscles. Once we've discussed these structures, we'll look at some clinical notes related to the female breast. But first let me give you an introduction to the female breast.
The breasts are secondary sex characteristic of females but are also present in a rudimentary or underdeveloped form in males. The breasts are the most prominent superficial structures in the anterior thoracic wall especially in women. Both female and male breasts are derived from the same embryological tissues but breasts develop more in females during puberty due to the production of estrogens – the sex hormones which stimulate breast development along with the growth hormone.
One of the main functions of the female breast is to produce and secrete milk for infants. Milk production by the female breast is known as lactation. Milk is released from the breast via the nipple which is a small projection of skin in the middle of the breast usually overlying the fourth intercostal space which is this space here. The nipple is surrounded by a circular pigmented area known as the areola.
The base of the breast is located from near the midline of the chest to the midaxillary line and from the second to sixth ribs. It overlies the pectoralis major muscle and part of the serratus anterior muscle. It also overlies the rectus sheath and the external oblique muscles. Milk is transported to the nipple by the lactiferous ducts which we can see here highlighted in green. The lactiferous ducts are lined by columnar epithelium and are supported by myoepithelial cells.
It's important to note that the female breast usually contains between 5 and 15 ducts and these ducts are only involved in milk transport. It was previously believed that the breasts contained a higher number of ducts and were also involved in milk storage. It was believed that the milk was stored in the dilation of the duct known as the lactiferous sinus, however, more recent studies have found that this is in fact incorrect. When a woman is not lactating, the lactiferous ducts are often blocked by a keratin plug which prevents bacteria from entering the ducts and therefore helps prevent infection. At the end of the lactiferous ducts, we can see clusters of alveoli known as lobules. These lobules are considered exocrine glands of the breast and they are the site of milk production and excretion in the breast.
So in this illustration we can see the lactiferous ducts here and located posterior to that, we can see the lobules of mammary gland. Surrounding these lobules is an abundant amount of adipose tissue which is responsible for storing and releasing fats and secreting numerous proteins. The amount of fats surrounding the glandular tissue determines the size of the non-lactating breasts. So now let's look at some of the supporting structures of the female breasts.
The female breasts overlie the pectoralis major muscle which is this muscle here. Underlying the pectoralis major are the ribs. Despite individual variations in size, the extent of the base of the breast is fairly constant. As I said previously, it usually extends from the midline to near the midaxillary line and from the second to the sixth ribs. Between the ribs, we can see the intercostal muscles which help form the chest wall and are involved in the mechanical aspect of breathing.
The breasts are held in their normal shape and structure by suspensory ligaments or Cooper's ligaments. These are also known as fibrocollagenous septa. These ligaments are connective tissues that run through and around the breast tissue helping the breast to maintain its structural integrity and suspending it from the clavicle. Without these ligaments, the breast tissue would sag under its own weight and lose its normal contour. A simpler way to think about this is that the suspensory ligaments almost act as an internal bra providing support to the breast tissue.
As well as pectoralis major, the breasts also overlie serratus anterior. This muscle is located on either side of the torso attaching to the first 8 ribs and inserting into the scapula. It is the superolateral aspect of the breast that overlies serratus anterior which we can see highlighted in green here. Inferiorly, the breast overlies the abdominal external oblique muscle which we can see here. This is the largest and most superficial abdominal muscle that originates from the fifth to twelfth ribs. We will now have a look at the blood vessels that supply the breast.
The main artery that supplies the breast as well as the anterior chest wall is the internal thoracic artery. This artery branches from the subclavian artery near its origin and sends branches through the intercostal spaces beside the sternum. The twelfth and third spaces are the largest and run downwards medial to the nipple. The venous drainage of the breast is mainly done by the internal thoracic vein. The internal thoracic vein arises from the superior epigastric vein and drains the chest wall as well as the breast. It drains into the brachiocephalic vein. It's important to note that there are other blood vessels involved in the blood supply of the breast but these will be covered more thoroughly in another tutorial.
To finish off this tutorial, we will go over some clinical notes relevant to the breast. Breast cancer is a relatively common disease that develops from breast tissue. Signs of breast cancer include dimpling of the skin over the breast, a lump within the breast and discharge from the nipple. There are many known risk factors for breast cancer including female gender, smoking, family history, older age, and hormone replacement therapy. It most commonly develops in either the ducts or the lobules. Cancers developing in the ducts are known as ductal carcinomas whereas cancers developing from the lobules are known as lobular carcinomas. Most types of breast cancer have a good survival rate and are usually treated with a combination of surgery, chemotherapy and radiotherapy.
The breast can also be affected by benign conditions, the most common of which being fibrocystic breast disease. This disease is characterized by the presence of noncancerous lumps within the breast that can often cause tenderness and swelling. These lumps usually have smooth edges and are free-moving in contrast to cancerous lumps which are usually fixed in position and have irregular edges. Therefore, it's important for health professionals to ask specific questions about the breast lump in order to differentiate between these two diseases.
It is also important to note that the upper lateral region of the breast can project into the lateral margin of the pectoralis major muscle and therefore into the axilla or armpit region. It can extend as far as the apex of the axilla and is thus extremely important for evaluation of the breast.
That concludes our tutorial on female breast structure. I hope you enjoyed it and thank you for listening.
Now that you just completed this video tutorial, then it’s time for you to continue your learning experience by testing and also applying your knowledge. There are three ways you can do so here at Kenhub. The first one is by clicking on our “start training” button, the second one is by browsing through our related articles library, and the third one is by checking out our atlas.
Now, good luck everyone, and I will see you next time.