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    Related Topics

    From Lymphatic System

    Mesenteric Lymph Nodes
    Drain the intestines and abdominal structures.
    Jugular Trunk
    Drains lymph from the head and neck.
    Lymph Nodes
    Small structures that filter lymph and store immune cells.
    Deep Cervical Lymph Nodes
    Located along internal jugular vein; receive lymph from head and neck.
    Lateral Axillary Nodes
    Located along the humerus in the axilla.
    Waldeyer’s Ring
    Ring of lymphoid tissue surrounding the naso- and oropharynx.
    Lumbar Trunk
    Drains lower limbs and pelvic organs.
    Preaortic Nodes
    Located in front of the aorta.
    Appendix
    Lymphoid-rich structure of the large intestine.
    Pretracheal Nodes
    Located anterior to the trachea.
    Intestinal Trunk
    Drains lymph from the intestines.
    Palatine Tonsils
    Located on each side of the oropharynx.
    Peyer’s Patches
    Lymphoid nodules in the small intestine.
    Submental Lymph Nodes
    Drain the floor of the mouth and central lower lip.
    Parotid Lymph Nodes
    Drain the lateral face and scalp.
    Anterior Mediastinal Nodes
    Drain anterior thoracic structures.
    BALT
    Bronchus-associated lymphoid tissue.
    Para-aortic Lymph Nodes
    Drain abdominal viscera and lower limbs.
    Pharyngeal Tonsil
    Located in the nasopharynx (adenoids).
    Mastoid Lymph Nodes
    Drain the posterior scalp and ear.
    Subclavian Trunk
    Drains lymph from the upper limbs.
    SALT
    Skin-associated lymphoid tissue.
    Occipital Lymph Nodes
    Drain the back of the scalp.
    Subscapular Axillary Nodes
    Located along the posterior chest wall.
    Popliteal Lymph Nodes
    Drain the foot and leg.

    Posterior Mediastinal Nodes

    Reviewed by our medical team

    Drain posterior thoracic structures.

    1. Overview

    The posterior mediastinal lymph nodes are a group of deep thoracic lymph nodes situated within the posterior mediastinum. These nodes are responsible for filtering lymph from structures such as the esophagus, posterior pericardium, thoracic aorta, and posterior intercostal spaces. Though often overshadowed by their anterior and middle mediastinal counterparts, posterior mediastinal nodes play a vital role in thoracic immune surveillance and are frequently involved in systemic diseases such as cancer and tuberculosis.

    2. Location

    Posterior mediastinal lymph nodes are located in the posterior mediastinum, which is the region of the thoracic cavity bounded by:

    • Anteriorly: The pericardium and tracheobronchial lymph nodes

    • Posteriorly: The vertebral column

    • Superiorly: The plane at the sternal angle (T4–T5 level)

    • Inferiorly: The diaphragm

    • Lateral boundaries: The mediastinal pleurae

    They are typically found adjacent to the thoracic aorta, azygos and hemiazygos veins, and along the esophagus. These nodes connect with nearby mediastinal and intercostal nodes and eventually drain into the thoracic duct.

    3. Structure

    Posterior mediastinal lymph nodes are small, oval, encapsulated structures composed of lymphoid tissue. Their typical structural components include:

    • Capsule: A fibrous connective tissue covering

    • Cortex: Contains lymphoid follicles rich in B cells

    • Paracortex: Dominated by T lymphocytes and antigen-presenting dendritic cells

    • Medulla: Houses plasma cells, macrophages, and medullary sinuses

    • Afferent lymphatic vessels: Receive lymph from the esophagus, posterior pericardium, diaphragm, and thoracic wall

    • Efferent lymphatic vessels: Drain into the thoracic duct, which ultimately empties into the left venous angle

    4. Function

    The posterior mediastinal nodes serve several key roles in the immune and lymphatic systems:

    • Filtration of lymph: Remove pathogens, foreign material, and cancer cells from lymph originating in posterior thoracic structures

    • Immune activation: Act as sites for antigen presentation and lymphocyte activation

    • Relay function: Serve as intermediate lymphatic stations en route to the thoracic duct

    5. Physiological Role(s)

    These lymph nodes are part of the thoracic immune defense network, with key physiological roles including:

    • Esophageal immunity: Protect against infection and inflammation arising from the esophagus or surrounding connective tissues

    • Cardiothoracic protection: Participate in immune surveillance of the posterior pericardium and thoracic aorta

    • Drainage integration: Link lower intercostal and diaphragmatic lymphatics to central venous return via the thoracic duct

    Their deep location and vascular proximity make them strategically positioned for detecting systemic and thoracic diseases.

    6. Clinical Significance

    Cancer Metastasis

    Posterior mediastinal nodes may be involved in the spread of cancers from:

    • Esophagus (especially mid and lower esophageal carcinoma)

    • Lungs (particularly lower lobe tumors)

    • Stomach and pancreas (via transdiaphragmatic lymphatic spread)

    Their involvement is a key staging factor in thoracic and upper abdominal malignancies. Enlarged nodes may indicate advanced disease requiring biopsy or oncologic treatment.

    Tuberculosis and Sarcoidosis

    Posterior mediastinal lymphadenopathy may occur due to granulomatous diseases:

    • Tuberculosis (TB): Often presents with bilateral, caseating nodal enlargement

    • Sarcoidosis: Non-caseating granulomas involving multiple mediastinal lymph node groups

    Such conditions may cause pressure effects on the esophagus or thoracic duct, leading to dysphagia or chylothorax, respectively.

    Compression Syndromes

    Enlarged posterior mediastinal nodes may compress:

    • Esophagus: Causing dysphagia or difficulty swallowing

    • Thoracic duct: Leading to chylous leakage (chylothorax)

    • Sympathetic chain or spinal nerves: Rarely causing back pain or referred symptoms

    Imaging and Diagnostic Evaluation

    Due to their deep location, these nodes are not clinically palpable and require imaging for assessment:

    • CT scan: Best for identifying size, calcification, and anatomical relations

    • PET-CT: Useful in cancer staging and detecting metabolically active disease

    • Endoscopic ultrasound (EUS): Can access and sample posterior mediastinal nodes adjacent to the esophagus

    • Biopsy: Needed for definitive diagnosis in suspected infections or malignancy

    Surgical Considerations

    In esophageal or thoracic oncology, posterior mediastinal lymph node dissection may be performed for accurate staging or therapeutic clearance. Care must be taken to avoid:

    • Thoracic duct injury

    • Aortic or venous structure compromise

    Minimally invasive approaches such as video-assisted thoracoscopic surgery (VATS) have improved access to these nodes.

    Did you know? The lymphatic system works alongside the circulatory system to help regulate fluid balance and immune function.