Thoracic lymph node stations

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Thoracic lymph nodes are divided into 14 stations as defined by the International Association for the Study of Lung Cancer (IASLC) , principally in the context of oncologic staging. For the purpose of prognostication, the stations may be grouped into 7 zones.  The IASLC definitions leave some ambiguous regions which can lead to misclassification .

Supraclavicular zone

Station 1 (left/right): low cervical, supraclavicular, and sternal notch nodes
  • superior border: lower margin of the cricoid cartilage
  • inferior border: strictly the IASLC defines this as the clavicles, which leads to ambiguity, particularly as the clavicle is mobile - a more definitive anatomical boundary is the thoracic inlet, i.e. 1 rib  
  • left (1L) and right (1R) are divided by the mid-line of the trachea
  • station 1 nodes are outside the mediastinum and staged as an N3 disease; despite this, they can sometimes be treated with radical intent if they are encompassable in a radiotherapy field

Upper zone (superior mediastinal nodes)

Station 2 (left/right): upper paratracheal nodes
  • superior border: apex of lung / pleural space, thoracic inlet
  • left (2L) and right (2R) are divided along the left lateral border of the trachea, not the midline
  • inferior border of 2R: at the intersection of caudal margin of the left brachiocephalic vein with the trachea, i.e. abuts 4R
  • inferior border of 2L: superior border of the aortic arch, i.e. abuts 4L
Station 3A & 3P: pre-vascular and retrotracheal nodes
Station 4 (left/right): lower paratracheal nodes
  • left (4L) and right (4R) are divided along the left lateral border of the trachea, not the mid-line
  • 4R:
    • superior border: intersection of caudal margin of the left brachiocephalic vein with the trachea, i.e. abuts 2R
    • inferior border: inferior border of the azygos vein
  • 4L:
    • superior border: superior border of the aortic arch, i.e. abuts 2L
    • inferior border: superior border of the left main pulmonary artery
  • pre-carinal nodes
    • lymph nodes anterior to the tracheal bifurcation are inferior to the above anatomic definitions and are thus technically unclassified by IASLC
    • these nodes are in the mediastinum (N2) and their surgical management mirrors that of 4R/4L lymph nodes, hence, pre-carinal nodes are best classified as part of the 4R/4L stations

Aortopulmonary zone

Station 5: subaortic nodes (aortopulmonary window)
  • lateral to ligamentum arteriosum
  • superior border: inferior border of the aortic arch
  • inferior border: superior border of the left main pulmonary artery
Station 6: para-aortic nodes, ascending aorta or phrenic
  • anterior and lateral to the ascending aorta and aortic arch
  • superior border: line tangential to the upper border of the aortic arch
  • inferior border: lower border of the aortic arch

Subcarinal zone

Station 7: subcarinal nodes

Lower zone (inferior mediastinal nodes)

Station 8 (left/right): para-esophageal nodes (below carina)
  • superior border: station 7, i.e. upper border of lower lobe bronchus on left, and lower border of bronchus intermedius on right
  • inferior border: diaphragm
Station 9 (left/right): pulmonary ligament nodes
  • lying within the pulmonary ligament
  • superior border: inferior pulmonary vein
  • inferior border: diaphragm

Hilar and interlobar zone (pulmonary nodes)

Station 10 (left/right): hilar nodes
  • immediately adjacent to mainstem bronchus and hilar vessels
  • superior border: lower border of the azygos vein on the right, the upper border of the pulmonary artery on the left
Station 11: interlobar nodes
  • between the origin of the lobar bronchi

Peripheral zone (pulmonary nodes)

Station 12: lobar nodes
  • adjacent to lobar bronchi
Station 13: segmental nodes
  • adjacent to segmental bronchi
Station 14: sub-segmental nodes
  • adjacent to subsegmental bronchi
  • subsegmental