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Lymphatic System of the Trunk and Limbs

Q: Which lymph nodes are considered parietal nodes of the pelvis?

Pelvic lymph nodes include: Lateral common iliac nodes (nodi lymphoidei iliaci communes laterales);External iliac nodes (nodi lymphoidei iliaci externi);Internal iliac node (nodus lymphoideus iliacus internus);Sacral nodes (nodi lymphoidei sacrales).

Systema lymphaticum

For medical students2 min readUpdated 2026-10-10

The lymphatic system is a vital part of the vascular network responsible for interstitial fluid drainage, clearance of foreign agents, and immune defense. Its main elements in the trunk and limbs include lymphatic capillaries, vessels, nodes, as well as major collecting trunks and ducts.

ClassificationVessels are divided into superficial (subcutaneous) and deep (running along major blood vessels).

Lymph nodesAct as filters; lymph flow is interrupted here for cleansing and lymphocyte enrichment.

Thoracic ductDrains lymph from 3/4 of the body, emptying into the left venous angle.

Right lymphatic ductDrains lymph from the right upper quarter of the body, emptying into the right venous angle.

Lymphatic Vessels and Nodes

Depending on their depth, lymphatic vessels (vasa lymphatica) are divided into two main groups:

Superficial lymphatic vessels (vasa lymphatica superficialia) — run in the subcutaneous adipose tissue layer.
Deep lymphatic vessels (vasa lymphatica profundae) — run parallel to major vascular (primarily arterial) trunks.

Vessels frequently communicate, forming lymphatic plexuses (plexus lymphatici). Furthermore, anastomoses exist between the superficial and deep networks.

Lymph nodes (nodi lymphoidei / lymphatici) are located along the path of the vessels. They function as biological filters: lymph enters via afferent vessels (vasa afferentia), flows through the node's sinuses (where it is filtered of bacteria and tumor cells and enriched with lymphocytes), and then leaves through efferent vessels (vasa efferentia), which emerge from the hilum (hilum). Groups of nodes draining lymph from a specific region are called regional nodes.

Internal Structure of a Lymph Node

Externally, the node is covered by a dense connective tissue capsule (capsula) containing smooth muscle cells (allowing the node to contract and propel lymph). Trabeculae extend inward from the capsule, forming the organ's framework.

The parenchyma of the node consists of lymphoid tissue:

Cortex (cortex) — located peripherally.
Medulla (medulla) — located centrally and forming medullary cords.

Between the parenchyma and the framework (capsule and trabeculae) lie endothelial-lined spaces called sinuses (subcapsular/marginal, trabecular/intermediate, medullary/terminal). Lymph flows directly through these spaces.

Central Lymphatic Ducts

All lymph from the body ultimately collects into two large ducts that empty into the venous system.

1. Thoracic duct (Ductus thoracicus) The largest lymphatic collector. It collects lymph from the lower limbs, pelvis, abdominal cavity, as well as the left halves of the thorax, neck, head, and the left upper limb (i.e., 3/4 of the body).

Originates in the abdominal cavity (at the level of the second lumbar vertebra) as a dilation called the cisterna chyli (cisterna chyli).
Formed by the union of the intestinal trunk and two lumbar trunks (left and right).
Passes through the diaphragm into the thoracic cavity, ascends in the posterior mediastinum, and empties into the left venous angle.

2. Right lymphatic duct (Ductus lymphaticus dexter) A small vessel (only about 1–1.5 cm long) collecting lymph from the right upper limb, right halves of the thorax, neck, and head (1/4 of the body).

Formed by the union of the right jugular, subclavian, and bronchomediastinal trunks.
Empties into the right venous angle.

Lymphatic Drainage of the Lower Limb

The lymphatic system of the lower limbs consists of superficial and deep pathways heading toward the inguinal region.

Superficial lymphatic vessels originate from capillary networks on the foot. The medial group runs parallel to the great saphenous vein, while the lateral group runs along the small saphenous vein (some of these vessels are interrupted in popliteal nodes).
All lymph from the superficial tissues collects in the superficial inguinal lymph nodes (nodi lymphoidei inguinales superficiales). They lie subcutaneously in the upper third of the thigh and are divided into superomedial, superolateral, and inferior groups. Lymph from the lower abdominal wall, external genitalia, and perineum also drains here.
Deep inguinal lymph nodes (nodi lymphoidei inguinales profundi) lie beneath the fascia lata near the femoral vein (including Cloquet's/Rosenmüller's node). From the inguinal nodes, lymph drains into the external iliac nodes within the pelvic cavity.

Frequently asked questions

Which groups of lymph nodes drain the upper limb?

Lymph from the upper limb is drained by cubital, humeral, and axillary lymph nodes.

Cubital lymph nodes (nodi lymphoidei cubitales) — receive lymph from vessels running along the radial and ulnar arteries, as well as the posterior forearm.
Humeral lymph node — located at the border of the lower and middle thirds of the arm.
Axillary lymph nodes (nodi lymphoidei axillares) — receive lymph from superficial and deep vessels of the upper limb, including lateral axillary nodes (nodi lymphoidei axillares laterales).

Which lymph nodes are considered visceral nodes of the abdominal cavity?

Visceral groups associated with lymphatic drainage of abdominal organs and the digestive system include:

Hepatic lymph nodes (nodi lymphoidei hepatici);
Celiac nodes;
Gastric nodes;
Pyloric nodes (nodi lymphoidei pylorici);
Pancreaticoduodenal nodes (nodi lymphoidei pancreaticoduodenales);
Pancreatic nodes (nodi lymphoidei pancreatici);
Splenic nodes (nodi lymphoidei splenici).

Which lymph nodes are considered parietal nodes of the pelvis?

Pelvic lymph nodes include:

Lateral common iliac nodes (nodi lymphoidei iliaci communes laterales);
External iliac nodes (nodi lymphoidei iliaci externi);
Internal iliac node (nodus lymphoideus iliacus internus);
Sacral nodes (nodi lymphoidei sacrales).

Through which opening in the diaphragm does the thoracic duct enter the thoracic cavity?

The thoracic duct enters the thoracic cavity through the aortic hiatus of the diaphragm along with the aorta. The aortic hiatus is formed by the median arcuate ligament (lig. arcuatum medianum) between the crura of the lumbar part of the diaphragm.

What is the difference between afferent and efferent lymphatic vessels of a lymph node?

Afferent vessels enter the node on its convex side and deliver unfiltered lymph for cleansing. Efferent vessels carry away filtered lymph and exit through the hilum of the node.

Which areas of the body are drained by the thoracic duct?

The thoracic duct collects lymph from 3/4 of the body: the lower limbs, pelvis, abdomen, left half of the thorax, left upper limb, and left half of the head and neck.

What is the venous angle and what is its role in lymph return?

The venous angle is the junction of the internal jugular and subclavian veins. The thoracic duct empties into the left venous angle, and the right lymphatic duct empties into the right venous angle, thereby returning lymph to the bloodstream.

Where are the superficial inguinal lymph nodes located?

They are located in the upper third of the thigh, just below the inguinal ligament, in the subcutaneous tissue superficial to the fascia lata.

Go deeper

Structure and topography of lumbar, iliac, and sacral lymph nodes
Formation and course of major lymphatic trunks (jugular, subclavian, bronchomediastinal)
Topography of the thoracic duct in the thoracic cavity and its syntopy with the aorta and esophagus
Deep and superficial lymphatic pathways of the leg and their connection with popliteal nodes