Hello everyone! It's Megan from Kenhub here, and welcome to our tutorial on the lymphatics of the female breast. In today's tutorial, we're going to look at some of the lymph nodes that drain lymph from the female breast and the surrounding areas.
So here in this illustration, we can see an anterior view of the left breast. The majority of lymph nodes that drain the female breast are located in this region here which is known as the axilla. In this region, we have several groups of lymph nodes. Here, we've got a group which is called the pectoral axillary lymph nodes then here we have the subscapular axillary lymph nodes. Superior to this, we have the brachial axillary lymph nodes and the central axillary lymph nodes. Once we've discussed the lymphatics of the female breast, we'll also go over the clinical relevance of these lymph nodes and their role in the migration of cancer cells.
Before we start looking at the axillary lymph nodes, it's important to understand the basic anatomy of the lymphatic system. Each lymph node has at least one afferent component and one efferent component. Vessels that carry lymph to a lymph node are called afferent lymph vessels and those that carry lymph away from a lymph node are called efferent lymph vessels. Efferent lymph vessels may carry lymph to a vein into a lymphatic duct or even another lymph node. Therefore, it's important to remember that lymph nodes may receive lymph from both afferent and efferent vessels.
When considering the lymphatic drainage of the breast, you should know that it can be divided into four quadrants. These quadrants consist of the superomedial quadrant, the inferomedial quadrant, the superolateral quadrant and the inferolateral quadrant. This quadrant breakdown of the breast allows the clinician to further understand the drainage of lymph.
So let's start off by looking at the axillary lymph nodes. These nodes can be found in the axilla – an area where the upper limb joins the trunk of the body. Seventy-five percent of the lymph from the female breast drains into these lymph nodes typically from the lateral quadrants.
The axillary lymph nodes can be divided into six different groups, some of which I showed you at the beginning of this tutorial. These groups include the pectoral or anterior group, the apical group, the subscapular or posterior group, the brachial or lateral group, the central group, and the interpectoral group. Lymph from the pectoral, subscapular and brachial groups drain into the central group of lymph nodes.
Now let's have a look at these groups of lymph nodes in more detail starting with the pectoral group. The pectoral axillary lymph nodes also known as the anterior axillary lymph nodes are located along the course of the lateral thoracic artery and the lateral thoracic vein. These nodes drain lymph from the anterolateral skin and muscles of the chest wall and lateral quadrant of the breast. When examining a patient, these lymph nodes can be palpated in the medial part of the axilla against the chest wall on the border of the pectoralis major muscle and anterior axillary fold.
Next, let's have a look at the subscapular axillary lymph nodes otherwise known as the posterior axillary lymph nodes. These lymph nodes are located on the posterior wall of the axilla and, as you can see, along the course of the subscapular artery here and the subscapular vein here. These nodes drain lymph from the skin and muscles of the posteroinferior neck and the posterior thoracic wall.
The third group of lymph nodes that drain into the central axillary nodes are the brachial axillary lymph nodes which are also known as the lateral axillary lymph nodes. These lymph nodes are found medial to the axillary vein and drain lymph from most of the arm. The three previously mentioned groups drain into a common group of lymph nodes called the central axillary lymph nodes. There are usually three or four of these lymph nodes in total and they are embedded in the adipose tissue of the axilla. These lymph nodes are usually felt deep in the middle of the axilla and as mentioned previously, this group of lymph nodes receives lymph from the pectoral, subscapular and brachial lymph nodes.
Lymph from the central axillary lymph nodes will then drain into another group of lymph nodes called the apical lymph nodes. The apical lymph nodes are a group of six to twelve nodes located posterosuperior to the pectoralis minor muscle at the apex of the axilla. It receives efferents from other groups as well as afferents accompanying the cephalic vein and superior quadrants of the breast. Efferent vessels travel from the apical group and join together to form the subclavian trunk. The subclavian trunk then drains into the junction of the subclavian and internal jugular veins which is known as the jugular lymphatic trunk.
The final group of axillary lymph nodes that we'll look at are the interpectoral lymph nodes also known as the Rotter's lymph nodes. These lymph nodes are located between the pectoralis minor muscles and the pectoralis major muscles. Although these lymph nodes are not technically located in the axilla, they are often classified as axillary lymph nodes. They receive lymph from the mammary gland as well as the pectoralis muscles and their efferent vessels drain into the axillary lymphatic plexus.
There are few other lymph nodes that are not classified as axillary lymph nodes but also drain lymph from the breast which we'll now take a look at. The first group we'll talk about are the parasternal lymph nodes. These nodes are located here between the ribs in the anterior intercostal spaces. We can see in this illustration that they are located alongside the internal thoracic artery which we can see here and the internal thoracic vein which we can see here. These lymph nodes receive afferent vessels from the medial quadrants of the breast as well as areas of the abdomen. The efferent vessels usually join together and drain into the internal jugular and subclavian veins or the thoracic duct within the thoracic cage.
Another lymph node that drains breast is the paramammary lymph node which as you can see is located on the lateral side of the breast here. Luckily, the names of some of the lymph nodes that we're discussing today relate directly to their position in the body which makes them a bit easier to remember. For example, para means beside or adjacent to a structure and mammary refers to breast tissue. So the paramammary lymph node is a node that is located beside the breast. Another example of this is the parasternal lymph nodes which are lymph nodes located beside the sternum. Efferent lymph vessels from the paramammary lymph node drain into the pectoral axillary lymph nodes.
The last group of lymph nodes that we'll look at are the submammary lymph nodes. As the name suggests, these lymph nodes are located below the breast. These nodes drain lymph from the inferior quadrants of the breast and are located within the submammary space between the superficial fascia of the breast and fascia located over the pectoralis major muscle.
All of these lymph nodes that we have gone over have a lot of significance in clinical practice. In breast cancer, it's relatively common for cancer to spread to the regional lymph nodes, therefore, it's important to have a good knowledge of the lymphatic drainage of the breast. Breast cancer often metastasize to the axillary lymph nodes. An involvement of these lymph nodes is an important factor for prognosis. If metastases to any of the axillary lymph nodes is suspected, removal of these nodes is often carried out. This is known as axillary lymphadenectomy and is important for staging of the disease as well as hopefully preventing further spread. However, if lymphatic drainage is interrupted, it can lead to a buildup of fluid causing localized swelling which is referred to as a lymphoedema. If this fluid buildup occurs in the breast tissue then this can lead to the clinical sign known as peau d'orange or orange peel sign.
And that brings us to the end of this tutorial on lymphatics 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.