Arteries and veins of the female breast.
Hello everyone! It's Megan from Kenhub here, and welcome to our tutorial on blood vessels of the female breast. The female breast is a structure of vast variability in size and shape and undergoes many changes throughout life due to hormonal control. These hormones must travel through the vascular system in order to reach the breast tissue. During this tutorial, we'll discuss the arteries and veins associated with the female breast. We'll also bring in some clinical notes related to the breast vasculature. We will do this by mainly focusing on the image you can see in front of you which is an anterior view of the left breast. We'll begin this tutorial by looking at the arteries starting with the internal thoracic artery.
The internal thoracic artery is a branch of the subclavian artery and, in females, it's known as the internal mammary artery. On the left, we can see the structure more clearly. It descends inferiorly to lie posterior to the first 6 costal cartilages and lateral to the sternum. On the right, we can see it running alongside the parasternal lymph nodes and the internal thoracic vein. As I mentioned previously, the internal thoracic artery is a branch of the subclavian artery. Highlighted in green, we can see the internal thoracic arteries descending from the left subclavian artery and the right subclavian artery passing behind the subclavian veins.
The internal thoracic artery gives off perforating branches which pass through the first 5 or 6 intercostal spaces to supply the pectoralis major muscle and surrounding skin. In females, the second to fourth perforating branches give off medial mammary branches which supply the anteromedial part of the breast. We can see these branches here highlighted in green. The second perforating artery is the largest and supplies the upper breast, the nipple and the areola.
Now let's look at the arteries that supply the lateral aspect of the breast starting with the axillary artery. At the lateral border of the first rib, the subclavian artery becomes the axillary artery. The axillary artery has six branches in total and provides two sources of blood for the female breast. We will move on to look at one of these branches now which is the lateral thoracic artery. The lateral thoracic artery descends from the second portion of the axillary artery lateral to the pectoralis minor. It continues to run inferiorly along the serratus anterior muscle supplying this muscle as well as the pectoral muscles, subscapularis and the axillary lymph nodes.
In females, the lateral thoracic artery is large and gives off lateral mammary branches. In this zoomed-in image, we can see these branches highlighted in green. These branches curve around the lateral border of pectoralis major to supply the lateral aspect of the breast. The second source of arterial blood of the axillary artery is this vessel here – the pectoral branch of the thoracoacromial artery. This branch courses deep to the pectoralis major muscle and supplies it. It then gives off branches that pierce this muscle and supply the superior portion of the female breast.
The final arteries we'll take a look at are the posterior intercostal arteries. It's the second to fourth posterior intercostal arteries specifically that supply the breast. These arteries arise directly from the thoracic aorta and run along their corresponding intercostal spaces giving branches to the breast as they reach the more anterior aspects of the thoracic wall. All of the arteries that we've talked about today will travel through muscle, fascia or even the breast itself to supply all aspects of the female breast. This can be seen clearly here as the vessels reach all of the regions of the breast. We'll now move on to consider the veins of the female breast.
It's important to note that most of the venous drainage of the breast will mimic the arteries that we previously discussed, however, we'll still take a look at these veins and also at some of the larger veins that they drain into. The first vein we'll take a look at is the cephalic vein. The cephalic vein is a superficial vein that arises at the breast and runs at the lateral aspect of the forearm and arm. In this image, we can see the proximal part of the vein running through the deltopectoral groove before it drains into the axillary vein. This vein drains the anterolateral part of the upper limb as well as receiving blood from the superficial breast tissue.
Now let's take a closer look at the axillary vein. The axillary vein is formed by the union of the basilic vein and the brachial vein beginning at the lower border of the teres major muscle. The axillary vein follows the course of the axillary artery and ends where its counterpart begins at the lateral border of the first rib. This vein drains the chest wall and the pectoral muscles as well as receiving venous drainage of the breast. Like the cephalic vein, the basilic vein is a superficial vein that arises in the wrist region but instead it travels up the medial aspect of the forearm and arm. Here we can see the brachial vein uniting with the basilic vein highlighted in green to become the axillary vein.
The next vein we'll look at is the lateral thoracic vein which drains into the axillary vein. This vein receives venous blood from the serratus anterior and the pectoralis major muscles and follows the course of its corresponding artery that we saw earlier, the lateral thoracic artery. As I mentioned previously, at the lateral border of the first rib, the axillary vein becomes the subclavian vein. The subclavian vein follows the course of the subclavian artery before it joins with the internal jugular vein to become the brachiocephalic vein. The angle where the subclavian vein and the internal jugular vein unite is called the venous angle. Running in the intercostal spaces, we can see the posterior intercostal veins. The second to fourth intercostal veins drain some of the lateral aspect of the breast following their arterial partners. These veins will then join the azygos venous system in the thoracic cage before draining into the superior vena cava.
The next aspect of the venous drainage we'll look at is the internal thoracic veins. In the illustration on the right, we can see the left internal thoracic vein. This pair of veins lie in close proximity to the internal thoracic arteries and drain blood from the medial chest wall and the breasts. They follow the course of the internal thoracic artery and its branches before they drain into the brachiocephalic veins. So finally let's talk about the brachiocephalic veins that we just mentioned. The left brachiocephalic vein which we can see here is actually longer than the right because it needs to cross the midline of the body. It joins with its counterpart on the other side – the right brachiocephalic vein – to form the superior vena cava. The superior vena cava directs venous blood from the head, the neck, the upper limb and the thoracic cage to the heart.
To conclude this tutorial, we'll go over some clinical notes relevant to the blood vessels of the breast. The internal thoracic artery, otherwise known as the internal mammary artery, is often used as a graft for coronary artery bypass grafting. The internal thoracic artery is considered to be the gold standard for a bypass of the left anterior descending artery of the heart. During surgery, the internal thoracic artery is not removed from its site of origin and only one end is moved from the chest wall. The internal thoracic artery is considered to have better outcomes than the saphenous veins which previously were the most commonly used for coronary artery bypass grafting. This procedure does not normally affect the blood supply to the breast as the breast receives blood from multiple sources such as the lateral thoracic artery.
An understanding of the posterior intercostal veins is important clinically for the spread of breast cancer. If cancerous cells from the breast break off and migrate into the posterior intercostal veins, they can travel into the azygos system. As they approach the spine, they communicate with the spinal vertebrae and spinal cord via the external and internal vertebral plexuses allowing breast cancer to spread to the spine.
So that brings us to the end of our tutorial on blood vessels of the female breast. I hope you enjoyed it and thank you for listening.
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Now, good luck everyone, and I will see you next time.
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