Internal jugular chain (IJC): Deep cervical chain

Spinal accessory chain (SAC): Posterior triangle chain

Transverse cervical chain: Supraclavicular chain

Anterior cervical chain: Prelaryngeal, pretracheal, paratracheal nodes

Paratracheal node: Recurrent laryngeal node

Jugulodigastric node: “Sentinel” (highest) node, found at apex of IJC at angle of mandible

Virchow node: “Signal” node, lowest node of deep cervical chain

Troisier node: Most medial node of transverse cervical chain

Omohyoid node: Deep cervical chain node superior to omohyoid as it crosses jugular vein

Delphian node: Pretracheal node

In normal adult neck, may be up to 300 lymph nodes

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  Internal structures: Capsule, cortex, medulla, hilum

US appearances of normal cervical lymph node

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  Small, oval/reniform shape with well-defined margin

  
  
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  Homogeneous, hypoechoic cortex with echogenic fatty hilum

  
  
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  Hilar vascularity on color/power Doppler examination

Imaging-based nodal classification

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  Level I: Submental and submandibular nodes

  
  
  
  
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    Level IA: Submental nodes: Found between anterior bellies of digastric muscles

    
    
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    Level IB: Submandibular nodes: Found around submandibular glands in submandibular space

  
  
  
  
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  Level II: Upper IJC nodes: From posterior belly of digastric muscle to hyoid bone

  
  
  
  
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    Level IIA: Level II node anterior, medial, lateral, or posterior to IJV; if posterior to IJV, node must be inseparable from IJV; contains jugulodigastric nodal group

    
    
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    Level IIB: Level II node posterior to IJV with fat plane visible between node and IJV

  
  
  
  
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  Level III: Mid IJC nodes

  
  
  
  
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    From hyoid bone to inferior margin of cricoid cartilage

  
  
  
  
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  Level IV: Lower IJC nodes

  
  
  
  
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    From inferior cricoid margin to clavicle

  
  
  
  
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  Level V: Nodes of posterior cervical space/spinal accessory chain

  
  
  
  
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    SAC nodes lie posterior to back margin of sternocleidomastoid muscle

    
    
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    Level VA: Upper SAC nodes from skull base to bottom of cricoid cartilage

    
    
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    Level VB: Lower SAC nodes from cricoid to clavicle

  
  
  
  
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  Level VI: Nodes of visceral space

  
  
  
  
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    Found from hyoid bone above to top of manubrium below

    
    
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    Midline group of cervical lymph nodes

    
    
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    Includes prelaryngeal, pretracheal, and paratracheal subgroups

  
  
  
  
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  Level VII: Superior mediastinal nodes

  
  
  
  
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    Between carotid arteries from top of manubrium above to innominate vein below

  
  

Other nodal groups not included in standard imaging-based nodal classification

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  Parotid nodal group: Intraglandular or extraglandular

  
  
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  Retropharyngeal (RPS) nodal group: Medial RPS nodes and lateral RPS nodes (Rouvière node)

  
  
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  Facial nodal group

Nodal metastases from primary tumors are site specific; therefore, it is critical to understand usual patterns of lymphatic spread

Equivocal nodes outside usual pattern less suspicious

Likely location of primary tumor can be suspected in patients presenting with nodal mass

Nodal disease outside usual pattern may suggest aggressive tumor or prompt search for 2nd primary

RPS nodes and superior mediastinal nodes cannot be assessed by US

Useful US features suspicious of malignancy

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  Shape: Round, long:short axis ratio < 2

  
  
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  Loss of echogenic hilum

  
  
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  Presence of intranodal necrosis (cystic/coagulation)

  
  
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  Presence of extracapsular spread: Ill-defined margin

  
  
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  Peripheral/subcapsular flow on color/power Doppler ultrasound

  
  
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  Increased intranodal intravascular resistance: Resistive index (RI) > 0.8, pulsatility index (PI) > 1.6

  
  
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  Internal architecture: Punctate calcifications in metastatic node from papillary thyroid carcinoma, reticulated/pseudocystic appearance of lymphomatous node

No single finding sensitive or specific enough; these signs should be used in combination

Fine-needle aspiration biopsy helps to improve diagnostic accuracy

Tuberculous nodes mimic metastatic nodes

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  Differentiating features: Intranodal necrosis, nodal matting, soft tissue edema and displaced hilar vascularity/avascularity, calcification (post treatment)

Presence of malignant SCCa nodes on staging associated with 50% ↓ in long-term survival

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  If extranodal spread present, further 50% ↓

Location of metastatic nodes in neck may help predict site of primary tumor

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  RPS and posterior triangle nodes seen in nasopharyngeal carcinoma, and lower cervical nodes in lung cancer

  
  
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  When Virchow node found on imaging without upper neck nodes, primary not in neck, and whole-body imaging warranted