From the Guidelines
The lymph node levels in the neck are typically divided into six levels, each with distinct boundaries and characteristics.
Lymph Node Levels
- Level I: includes the submandibular and submental lymph nodes, located in the submandibular triangle
- Level II: includes the upper jugular lymph nodes, located around the upper part of the internal jugular vein
- Level III: includes the middle jugular lymph nodes, located around the middle part of the internal jugular vein
- Level IV: includes the lower jugular lymph nodes, located around the lower part of the internal jugular vein
- Level V: includes the posterior triangle lymph nodes, located in the posterior triangle of the neck
- Level VI: includes the anterior compartment lymph nodes, located in the anterior part of the neck, including the pretracheal and paratracheal lymph nodes 1
Key Points
- The classification of lymph node levels is important for determining the extent of neck dissection and for planning treatment in patients with head and neck cancers 1
- The type of neck dissection (comprehensive or selective) depends on the preoperative clinical staging and the location of the primary tumor 1
- Selective neck dissections are often recommended for patients with N0 disease, while comprehensive neck dissections are often recommended for patients with N3 disease 1
From the Research
Lymph Node Levels in the Neck
The lymph node levels in the neck are classified into several levels, each with distinct boundaries and characteristics. The main lymph node levels in the neck are:
- Level I: Submental and submandibular nodes
- Level II-IV: Upper, middle, and lower jugular nodes
- Level V: Posterior triangle nodes, subdivided into Va and Vb
- Level VI: Anterior compartment nodes, subdivided into VIa and VIb
- Level VII: Superior mediastinal nodes
Sublevels of Level VI
Level VI is further subdivided into two sublevels:
- Level VIa: Prelaryngeal, intercricothyroidal, pretracheal, and perithyroidal nodes
- Level VIb: Inferior laryngeal nodes As described by 2, the boundaries of level VIa and VIb are defined by the inferior border of the hyoid bone, the inferior border of the cricoid cartilage, and the posterior face of the thyroid gland.
Sublevels of Level V
Level V is also subdivided into two sublevels:
- Level Va: Upper posterior triangle nodes
- Level Vb: Lower posterior triangle nodes As discussed by 3, the superior boundary of level Va is defined by the apex of the convergence of the sternocleidomastoid muscle and trapezius muscle.
Consensus Guidelines for Neck Node Levels
The consensus guidelines for the delineation of neck node levels, as outlined by 4, define 10 node groups with concise descriptions of their main anatomic boundaries and normal structures juxtaposed to these nodes. These guidelines aim to reduce treatment variations and facilitate multi-institutional clinical trials.
Quantification of Lymph Nodes
The quantification of lymph nodes in selective neck dissection is important for surgeons and pathologists, as described by 5. The average number of lymph nodes removed for levels I-V is around 24, with 13 for levels I-III and 19 for levels II-IV.
Automated Delineation of Lymph Node Levels
Automated delineation of lymph node levels using deep learning algorithms, as described by 6, can be more efficient and consistent than manual delineation. The algorithm can accurately delineate lymph node levels, including levels Ib, II-IVa, VIa, VIb, VIIa, and VIIb, with high Dice similarity coefficients.