The basics<\/h3>\n<\/span>\n\n<\/span>\nComponents<\/h4>\n<\/span>\n\n\n- The fluid that flows through this system is known as lymph<\/strong> and consists of fluids filtered from the extracellular matrix \u2014 mostly from the blood.<\/li>
- Lymphoid organs<\/strong> are divided into primary <\/strong>and secondary<\/strong>:
- Primary lymphoid organs include those where immune cells divide and develop: the bone marrow<\/strong> and thymus<\/strong>.<\/li>
- Secondary lymphoid organs include those where most immune reactions occur: lymph nodes<\/strong>, spleen<\/strong>, tonsils <\/strong>(Waldeyer’s tonsillary ring<\/strong>), MALT <\/strong>(mucous-associated lymphatic tissue<\/strong>).<\/li><\/ul><\/li>
- Lymph nodes <\/strong>are small, bean-shaped structures located in very important locations throughout our bodies, they contain a filtration system consisting of specialized immune cells.<\/li><\/ul>\n\n\n\n
![\"This](\"https:\/\/meddists.com\/wp-content\/uploads\/2018\/09\/lymphatics-600x468.jpg\")
Figure 1. Venous angles and main lymphatic vessels<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\nThe lymphatic flow of the body<\/h4>\n<\/span>\n\n\nIn general, all the lymph from the right quadrant of the body drains to the lymphatic trunk<\/strong> (or duct<\/strong>), and the remaining \u00be are to the thoracic duct<\/strong>.<\/p>\n\n\n\n- The final destination for these two vessels are the venous angles <\/strong>(or angulus venosus<\/strong>) which are the joining point of the internal jugular vein and the subclavian vein<\/strong> on each side<\/li>
- As they drain to the venous angle, the lymph re-enters the general circulation<\/li><\/ul>\n\n\n<\/span>\n
Upper limb<\/h3>\n<\/span>\n\n\nLymphatic vessels originate from lymphatic plexuses in the hand, forearm, arm, and shoulder, and are divided into superficial and deep vessels which can communicate with each other:<\/p>\n\n\n\n
- The superficial tissues (skin) form ventral <\/strong>(palmar<\/strong> in the hand) and dorsal<\/strong> cutaneous plexuses<\/strong> that follow the superficial veins in the hand.<\/li>
- The deep tissues drain into the less numerous deep lymph vessels <\/strong>that follow the primary neurovasculature (large vessels such as the brachial, radial, and ulnar veins).<\/li><\/ul>\n\n\n\n
All lymphatics of the arm drain into lymph nodes in the axilla which are otherwise called axillary nodes<\/strong>. There are 20\u201330 axillary nodes that are generally divided into five groups<\/strong> based on their location.<\/p>\n\n\n\n- Humeral <\/strong>(lateral<\/strong>) nodes<\/strong><\/li>
- Pectoral <\/strong>(anterior<\/strong>) nodes<\/strong><\/li>
- Subscapular <\/strong>(posterior<\/strong>) nodes<\/strong><\/li>
- Central nodes<\/strong><\/li>
- Apical nodes<\/strong><\/li><\/ul>\n\n\n\n
The subscapular, central, and apical nodes are found within the axilla.<\/p>\n\n\n<\/span>\n Humeral (lateral) nodes<\/h4>\n<\/span>\n\n\n- Consist of 4-6 nodes that run posteromedial to the axillary vein.<\/li>
- Receive most of the lymphatic drainage from the upper limb.<\/li><\/ul>\n\n\n<\/span>\n
Pectoral (anterior) nodes<\/h4>\n<\/span>\n\n\n- Consist of 3-5 nodes that run along the lower border of the pectoralis minor muscle together with the lateral thoracic vessels.<\/li>
- Receive lymph mainly from the abdominal wall<\/strong> and the anterior thoracic wall<\/strong>, including most of the breast<\/strong> (especially the upper outer quadrant and mammary gland).<\/li><\/ul>\n\n\n<\/span>\n
Subscapular (posterior) nodes<\/h4>\n<\/span>\n\n\n- Consist of 6-7 nodes that run along the posterior axil\u00adlary wall and subscapular vessels. <\/li>
- Receive lymphatics from the posterior thoracic wall<\/strong>, the shoulder<\/strong>, and the neck<\/strong>.<\/li><\/ul>\n\n\n<\/span>\n
Central nodes<\/h4>\n<\/span>\n\n\n- Consist of 3-4 large nodes embedded in the axillary fat.<\/li>
- Receive drainage from efferent lymphatic vessels of humeral<\/strong>, subscapular<\/strong>, and pectoral<\/strong> groups of nodes.<\/li><\/ul>\n\n\n<\/span>\n
Apical nodes<\/h4>\n<\/span>\n\n\n- The most superior group of nodes which is located at the apex of the axilla.<\/li>
- Receive lymph from all<\/strong> other groups<\/strong> of axillary nodes, especially the central nodes. <\/li>
- Further drainage of lymphatics from nodes accompanying the proximal cephalic vein and vessels that drain the superior region of the mammary gland occurs. <\/li>
- Efferent vessels from the apical group merge to form the subclavian trunk.<\/li><\/ul>\n<\/span>
- The fluid that flows through this system is known as lymph<\/strong> and consists of fluids filtered from the extracellular matrix \u2014 mostly from the blood.<\/li>
- Lymphoid organs<\/strong> are divided into primary <\/strong>and secondary<\/strong>:
- Primary lymphoid organs include those where immune cells divide and develop: the bone marrow<\/strong> and thymus<\/strong>.<\/li>
- Secondary lymphoid organs include those where most immune reactions occur: lymph nodes<\/strong>, spleen<\/strong>, tonsils <\/strong>(Waldeyer’s tonsillary ring<\/strong>), MALT <\/strong>(mucous-associated lymphatic tissue<\/strong>).<\/li><\/ul><\/li>
- Lymph nodes <\/strong>are small, bean-shaped structures located in very important locations throughout our bodies, they contain a filtration system consisting of specialized immune cells.<\/li><\/ul>\n\n\n\n
Figure 1. Venous angles and main lymphatic vessels<\/strong> (Credit: OpenStax, CC BY-SA 4.0<\/a>)<\/figcaption><\/figure>\n\n\n<\/span>\n The lymphatic flow of the body<\/h4>\n<\/span>\n\n\n
In general, all the lymph from the right quadrant of the body drains to the lymphatic trunk<\/strong> (or duct<\/strong>), and the remaining \u00be are to the thoracic duct<\/strong>.<\/p>\n\n\n\n
- The final destination for these two vessels are the venous angles <\/strong>(or angulus venosus<\/strong>) which are the joining point of the internal jugular vein and the subclavian vein<\/strong> on each side<\/li>
- As they drain to the venous angle, the lymph re-enters the general circulation<\/li><\/ul>\n\n\n<\/span>\n
Upper limb<\/h3>\n<\/span>\n\n\n
Lymphatic vessels originate from lymphatic plexuses in the hand, forearm, arm, and shoulder, and are divided into superficial and deep vessels which can communicate with each other:<\/p>\n\n\n\n
- The superficial tissues (skin) form ventral <\/strong>(palmar<\/strong> in the hand) and dorsal<\/strong> cutaneous plexuses<\/strong> that follow the superficial veins in the hand.<\/li>
- The deep tissues drain into the less numerous deep lymph vessels <\/strong>that follow the primary neurovasculature (large vessels such as the brachial, radial, and ulnar veins).<\/li><\/ul>\n\n\n\n
All lymphatics of the arm drain into lymph nodes in the axilla which are otherwise called axillary nodes<\/strong>. There are 20\u201330 axillary nodes that are generally divided into five groups<\/strong> based on their location.<\/p>\n\n\n\n
- Humeral <\/strong>(lateral<\/strong>) nodes<\/strong><\/li>
- Pectoral <\/strong>(anterior<\/strong>) nodes<\/strong><\/li>
- Subscapular <\/strong>(posterior<\/strong>) nodes<\/strong><\/li>
- Central nodes<\/strong><\/li>
- Apical nodes<\/strong><\/li><\/ul>\n\n\n\n
The subscapular, central, and apical nodes are found within the axilla.<\/p>\n\n\n<\/span>\n
Humeral (lateral) nodes<\/h4>\n<\/span>\n\n\n
- Consist of 4-6 nodes that run posteromedial to the axillary vein.<\/li>
- Receive most of the lymphatic drainage from the upper limb.<\/li><\/ul>\n\n\n<\/span>\n
Pectoral (anterior) nodes<\/h4>\n<\/span>\n\n\n
- Consist of 3-5 nodes that run along the lower border of the pectoralis minor muscle together with the lateral thoracic vessels.<\/li>
- Receive lymph mainly from the abdominal wall<\/strong> and the anterior thoracic wall<\/strong>, including most of the breast<\/strong> (especially the upper outer quadrant and mammary gland).<\/li><\/ul>\n\n\n<\/span>\n
Subscapular (posterior) nodes<\/h4>\n<\/span>\n\n\n
- Consist of 6-7 nodes that run along the posterior axil\u00adlary wall and subscapular vessels. <\/li>
- Receive lymphatics from the posterior thoracic wall<\/strong>, the shoulder<\/strong>, and the neck<\/strong>.<\/li><\/ul>\n\n\n<\/span>\n
Central nodes<\/h4>\n<\/span>\n\n\n
- Consist of 3-4 large nodes embedded in the axillary fat.<\/li>
- Receive drainage from efferent lymphatic vessels of humeral<\/strong>, subscapular<\/strong>, and pectoral<\/strong> groups of nodes.<\/li><\/ul>\n\n\n<\/span>\n
Apical nodes<\/h4>\n<\/span>\n\n\n
- The most superior group of nodes which is located at the apex of the axilla.<\/li>
- Receive lymph from all<\/strong> other groups<\/strong> of axillary nodes, especially the central nodes. <\/li>
- Further drainage of lymphatics from nodes accompanying the proximal cephalic vein and vessels that drain the superior region of the mammary gland occurs. <\/li>
- Efferent vessels from the apical group merge to form the subclavian trunk.<\/li><\/ul>\n<\/span>
- Pectoral <\/strong>(anterior<\/strong>) nodes<\/strong><\/li>
- The deep tissues drain into the less numerous deep lymph vessels <\/strong>that follow the primary neurovasculature (large vessels such as the brachial, radial, and ulnar veins).<\/li><\/ul>\n\n\n\n
- As they drain to the venous angle, the lymph re-enters the general circulation<\/li><\/ul>\n\n\n<\/span>\n
- Secondary lymphoid organs include those where most immune reactions occur: lymph nodes<\/strong>, spleen<\/strong>, tonsils <\/strong>(Waldeyer’s tonsillary ring<\/strong>), MALT <\/strong>(mucous-associated lymphatic tissue<\/strong>).<\/li><\/ul><\/li>
- Lymphoid organs<\/strong> are divided into primary <\/strong>and secondary<\/strong>: