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Axillary lymph nodes: want to learn more about it?

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Axillary lymph nodes

The axillary lymph nodes are a collection of grouped lymph nodes found in the axillary region of the upper limb. The axillary region is commonly referred to as the ‘armpit’, although it is a three-dimensional space bound inferiorly by skin and anteriorly by the clavicle.

It is a quadrilateral space which changes shape based upon whether the arm is adducted or abducted.

The lymph nodes of the axillary region are responsible for the lymphatic drainage of a large section of human anatomy. Due to this arrangement and duty, they have a particular clinical relevance.

This is particularly evident with breast cancer, where axillary lymph node status, with regards to cancer, defines the treatment algorithm and approach. In this article we will discuss the anatomy and function of the axillary lymph nodes. In addition we will discuss function and clinical relevance. 

Location

The axillary lymph nodes are located within the axillary region of the upper limb. They are approximately 20 to 30 (up to 40 have been noted) separate nodes which function to drain the:

  • vessels of the upper limb
  • chest walls
  • abdomen, above the umbilicus
  • lateral quadrant of the breast

Lymph flow is similar to venous blood flow. Lymph is conveyed towards the heart.

Axillary lymph nodes

Anterior group

These are also known as the pectoral group. They can be located across the inferior border of the pectoralis minor muscle and the superior border of the pectoralis major muscle. There are usually 4-5 large nodes. The lymph flows from the anterolateral aspect of the abdominal wall superior to the level of the umbilicus and the lateral quadrants of the breast. It coveys the lymph to more central nodes.

Pectoral axillary lymph nodes (ventral view)

Posterior group

This group is also known as the subscapular group. This group of 6-7 nodes can be found anterior to the subscapularis muscle and receives superficial lymph vessels located more commonly within the upper portion of the back and posterior neck. However, these can receive lymph from as far inferior as the superior border of the iliac crests.

Subscapular axillary lymph nodes (ventral view)

Lateral group

This group of 4-6 nodes can be found against the axillary vein. The vast majority of the lymph vessels of the upper limb flow into this group. The superficial group of nodes however, drains the lateral aspect of the upper limb and flows into the infraclavicular nodes.

Central group

This group of 3-4 nodes is found at the base and centrally located in the axilla. These nodes are interspread amongst the adipose (fat) of the region. These are the most important group of nodes in terms of drainage because these receive lymph flow from the three groups of nodes mentioned above (anterior, posterior, and lateral).

Central axillary lymph nodes (ventral view)

Apical group

This group of 4-5 nodes lies at the apex of the axilla and is located at the lateral border of the first rib. It is also referred to as the subclavicular group. This group receives efferent lymph vessels from the other axillary group of nodes. The apical group of nodes then drains into the subclavian lymph trunk. The drainage is different on the left and right sides. The left side axillary drainage flows into the thoracic duct, whereas on the right side the drainage is into the right lymphatic trunk.

Apical axillary lymph nodes (ventral view)

Infraclavicular group

This group is also known as the deltopectoral group. They cannot be referred to as axillary lymph nodes as they are located outside the axillary fossa and the axillary region. However, they do form a close association with the axillary group and lie in the deltopectoral groove (muscular superficial space between the deltoid and the pectoralis major). This space is also where the cephalic vein passes. In addition to this, this lymph node group of 2-3 nodes drains the major muscles of the forearm, hand, and arm, as well as the superficial lymph vessels of surrounding regions.

Thoracic duct

Cisterna chyli

The thoracic duct is main lymphatic duct of the body. It conveys the lymph from the lower limbs, abdomen, and the left side of trunk, upper limb, neck, and face. A portion of the thoracic duct in the abdomen is a dilated sac referred to as the ‘cisterna chyli’ or milk tank. This is because it contains the lymph fluid from the intestines, which is rich in chyle. This chyle is formed by fatty molecules (emulsified fats) and lymph from the lacteals. It is different from the lymph vessels that drain the limbs, where the drainage is purely lymph, and therefore clearer.

The thoracic duct is typically around 40 cm in length and has a diameter of 3-5 millimeters. The drainage of the thoracic duct is into the junction of the left jugulars and left subclavian vein. It is here that the lymphatic drainage of the bowels and body enters the systemic circulation. The drainage of the right upper limb, thorax, head, and neck drains into the right lymphatic duct.

Axillary lymph nodes: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

“I would honestly say that Kenhub cut my study time in half.” – Read more. Kim Bengochea Kim Bengochea, Regis University, Denver

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