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    Related Topics

    From Lymphatic System

    Sacral Lymph Nodes
    Drain the pelvic floor and rectum.
    Mastoid Lymph Nodes
    Drain the posterior scalp and ear.
    SALT
    Skin-associated lymphoid tissue.
    Superficial Cervical Lymph Nodes
    Drain superficial structures of the head and neck.
    Right Lymphatic Duct
    Drains right upper quadrant of the body.
    Preaortic Nodes
    Located in front of the aorta.
    NALT
    Nasal-associated lymphoid tissue.
    BALT
    Bronchus-associated lymphoid tissue.
    Lateral Axillary Nodes
    Located along the humerus in the axilla.
    Occipital Lymph Nodes
    Drain the back of the scalp.
    Inguinal Lymph Nodes
    Drain the lower limbs and external genitalia.
    Palatine Tonsils
    Located on each side of the oropharynx.
    Lingual Tonsils
    Located at the base of the tongue.
    Apical Axillary Nodes
    Located at the apex of the axilla.
    Tracheobronchial Nodes
    Drain lungs and bronchi.
    Deep Cervical Lymph Nodes
    Located along internal jugular vein; receive lymph from head and neck.
    Pectoral Axillary Nodes
    Located along the anterior chest wall.
    Lymph Nodes
    Small structures that filter lymph and store immune cells.
    Mesenteric Lymph Nodes
    Drain the intestines and abdominal structures.
    Cisterna Chyli
    Dilated sac at the start of the thoracic duct.
    Bronchomediastinal Trunk
    Drains lymph from thoracic organs.
    Pharyngeal Tonsil
    Located in the nasopharynx (adenoids).
    Waldeyer’s Ring
    Ring of lymphoid tissue surrounding the naso- and oropharynx.
    Thoracic Duct
    Main lymphatic duct draining most of the body.
    Tubal Tonsils
    Near openings of the auditory tubes.

    Subclavian Trunk

    Reviewed by our medical team

    Drains lymph from the upper limbs.

    1. Overview

    The subclavian trunk is a major lymphatic vessel that drains lymph from the upper limbs, superficial thoracic wall, and portions of the breast. It acts as one of the main conduits by which lymph collected from peripheral tissues enters the central lymphatic system. The subclavian trunk ultimately contributes to returning lymph to the venous circulation, thereby maintaining fluid balance and supporting immune surveillance.

    2. Location

    The subclavian trunk is located in the root of the neck, near the junction of the internal jugular and subclavian veins. There are typically two subclavian trunks — one on each side of the body:

    • Right subclavian trunk: Empties into the right lymphatic duct or directly into the junction of the right subclavian and right internal jugular veins.

    • Left subclavian trunk: Joins the thoracic duct, which then drains into the venous angle between the left subclavian and left internal jugular veins.

    Each subclavian trunk originates from the confluence of efferent vessels from axillary lymph nodes, along with contributions from superficial and deep lymphatics of the upper limb and adjacent thoracic regions.

    3. Structure

    The subclavian trunk is a short but wide lymphatic vessel, formed by the merging of multiple collecting vessels. Like other lymphatic vessels, its wall has three layers:

    • Endothelium: A single layer of endothelial cells that lines the lumen.

    • Tunica media: Composed of smooth muscle cells that contract rhythmically to aid lymph propulsion.

    • Tunica adventitia: Outer connective tissue layer providing support and anchoring to adjacent tissues.

    The trunk contains valves to ensure unidirectional lymph flow, and its smooth muscle allows for peristaltic-like contractions. It may vary in length and exact drainage pattern between individuals.

    4. Function

    The subclavian trunk plays a vital role in transporting lymph toward the central venous system. Its primary functions include:

    • Drainage of lymph: It receives lymph from the upper limb, anterior and lateral thoracic wall, and breast (especially via the axillary lymph nodes).

    • Transfer to central system: It channels filtered lymph into the right lymphatic duct or thoracic duct, depending on the side, ensuring return of lymph to the bloodstream.

    • Support immune transport: It carries antigen-presenting cells and immune factors toward the venous circulation for systemic distribution.

    5. Physiological Role(s)

    As a major lymphatic conduit, the subclavian trunk serves essential physiological roles:

    • Maintenance of fluid homeostasis: It helps return interstitial fluid and plasma proteins from the upper extremities back into the blood, preventing fluid accumulation (edema).

    • Immune function: The trunk transports lymph containing lymphocytes, antigens, and dendritic cells to central lymphatic structures and eventually into the bloodstream.

    • Lipid transport: Indirectly supports absorption and transport of dietary fats (via thoracic duct on the left), especially when integrated with thoracic lymph flow.

    Its integration into the lymphovascular junction ensures that lymph re-enters circulation without significant loss of proteins or immune components.

    6. Clinical Significance

    Lymphatic Obstruction

    Blockage of the subclavian trunk can lead to localized or regional lymphedema, particularly in the upper limbs. Causes include:

    • Surgical trauma: Especially during axillary clearance or lymph node dissection in breast cancer treatment.

    • Radiation fibrosis: Following radiotherapy to the thoracic or axillary regions.

    • Lymphatic metastasis: Tumor infiltration may compress or invade the subclavian trunk.

    Lymphedema of the Arm

    Obstruction or damage to lymphatic vessels draining into the subclavian trunk, especially post-mastectomy or lymphadenectomy, can result in arm swelling and chronic discomfort. Management includes compression therapy, physiotherapy, and, in advanced cases, microsurgical reconstruction (e.g., lymphovenous anastomosis).

    Lymphatic Spread of Malignancy

    Because it drains lymph from the breast and upper thorax, the subclavian trunk is a potential route for metastatic spread of:

    • Breast carcinoma

    • Lung carcinoma (especially apical tumors)

    • Melanoma or soft tissue sarcomas of the upper limb or chest wall

    Involvement of lymphatic trunks may indicate advanced disease and guide decisions on systemic therapy or extended radiation fields.

    Imaging and Surgical Relevance

    • Lymphoscintigraphy or ICG lymphography: Used to assess lymphatic flow and identify blockages.

    • Sentinel lymph node mapping: In breast cancer surgery, knowledge of subclavian drainage helps guide sentinel node identification.

    • Catheter placement: Central venous catheters inserted near the subclavian vein must avoid damaging nearby lymphatic structures.

    Did you know? Lymph moves through the lymphatic vessels with the help of muscle contractions and the flow of bodily fluids.