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Cervical lymph node levels

Som 1999 · AJCCCTMRIStaging
Figure · click to enlarge
Cervical lymph node levels. Image: Frank Gaillard, Radiopaedia.org, CC BY-NC-SA

Imaging-based level classification using landmarks visible on axial CT/MRI. Levels track the clinical (AAO-HNS) system.

LevelBoundaries on axial imaging
IASubmental. Between the medial margins of the anterior bellies of the digastric muscles, above the hyoid body and below the mylohyoid.
IBSubmandibular. Below mylohyoid, above hyoid body, posterior to the anterior belly of digastric and anterior to the back of the submandibular gland.
IIASkull base to bottom of hyoid body. Posterior to back of submandibular gland, anterior to back of SCM. Node anterior, medial, lateral to the IJV, or posterior but inseparable from it.
IIBSame craniocaudal range as IIA. Node posterior to the IJV with a fat plane between node and vein.
IIIBottom of hyoid body to bottom of cricoid arch. Anterior to back of SCM, lateral to medial margin of common/internal carotid.
IVBottom of cricoid to clavicle. Anterior to a line from back of SCM to posterolateral margin of anterior scalene; lateral to medial carotid margin.
VAPosterior triangle, skull base to bottom of cricoid. Posterior to back of SCM, anterior to anterior edge of trapezius.
VBPosterior triangle, bottom of cricoid to clavicle. Posterior to line from back of SCM to posterolateral margin of anterior scalene.
VICentral (visceral). Between the medial margins of the carotids, bottom of hyoid body to top of manubrium.
VIISuperior mediastinal. Between the carotids, below top of manubrium, above the innominate vein.
SCSupraclavicular. At or caudal to the clavicle on the scan where it is seen in full, above and medial to the ribs.
RPRetropharyngeal. Within 2 cm of skull base, medial to the internal carotid arteries.

Landmarks to anchor on

  • Hyoid body bottom: II → III transition. Cricoid bottom: III → IV and VA → VB transition.
  • Back of submandibular gland: I vs II. Back of SCM: II/III/IV vs V.
  • Medial carotid margin: lateral levels vs VI/RP.
Size thresholds commonly used: short axis >10 mm (>11 mm for jugulodigastric IIA). Necrosis, extranodal extension and rounded shape matter more than size.

Sources

  1. Som PM, Curtin HD, Mancuso AA. An imaging-based classification for the cervical nodes designed as an adjunct to recent clinically based nodal classifications. Arch Otolaryngol Head Neck Surg. 1999;125:388–396.PubMed ↗
  2. Som PM, Curtin HD, Mancuso AA. Imaging-based nodal classification for evaluation of neck metastatic adenopathy. AJR Am J Roentgenol. 2000;174:837–844.PubMed ↗
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Radessential summarizes published classification systems for practicing radiologists. Summaries are condensed; confirm details against the cited source before relying on them for patient care.