Lymph node levels of the neck

The lymph nodes in the neck have historically been divided into at least six anatomic neck lymph node levels for the purpose of head and neck cancer staging and therapy planning. Differing definitions exist across specialties ^1-4. The following is a synthesis of radiologically useful boundaries for each level.

Level I: submental and submandibular

• superiorly: mylohyoid muscle and mandible
• inferiorly: inferior border of the hyoid bone
• anteriorly: platysma muscle
• posteriorly: posterior border of the submandibular gland

​There are two sublevels:

• level Ia (submental nodes): anteromedial between the anterior bellies of both digastric muscles
• level Ib (submandibular nodes): posterolateral to the anterior belly of the digastric muscles

Level II: upper internal jugular (deep cervical) chain

• superiorly: base of the skull at the jugular fossa
• inferiorly: inferior border of the hyoid bone
• anteriorly: posterior border of the submandibular gland
• posterolaterally: posterior border of the sternocleidomastoid muscle
• medially: medial border of the internal carotid artery

​There are two sublevels:

• level IIa: inseparable from or anterior to the posterior edge of the internal jugular vein; includes jugulodigastric nodal group
• level IIb: posterior to and separable by a fat plane from the internal jugular vein

Level III: middle internal jugular (deep cervical) chain

• superiorly: inferior border of the hyoid bone
• inferiorly: inferior border of the cricoid cartilage
• anteriorly: anterior border of the sternocleidomastoid muscle
• posterolaterally: posterior border of the sternocleidomastoid muscle
• medially: medial border of the common carotid artery

Level IV: lower internal jugular (deep cervical) chain

• superiorly: inferior border of the cricoid cartilage
• inferiorly: level of the clavicle
• anteriorly: anterior border of the sternocleidomastoid muscle
• posterolaterally: oblique line drawn through the posterolateral edge of the sternocleidomastoid muscle and the lateral edge of the anterior scalene muscle ²
• medially: medial border of the common carotid artery
• includes medial supraclavicular nodes including Virchow node ¹

Level V: posterior triangle

• superiorly: skull base at the apex of the convergence of sternocleidomastoid and trapezius muscles
• inferiorly: level of the clavicle
• anteromedially: posterior border of the sternocleidomastoid muscle
• posterolaterally: anterior border of the trapezius muscle

​There are two sublevels:

• level Va: superior half, superior to inferior border of the cricoid cartilage (posterior to levels II and III); includes spinal accessory nodes
• level Vb: inferior half, inferior to inferior border of the cricoid cartilage (posterior to level IV); includes lateral supraclavicular nodes ¹

Level VI: central (anterior) compartment

• superiorly: inferior border of hyoid bone
• inferiorly: superior border of manubrium (suprasternal notch)
• anteriorly: platysma muscle ⁸
• posteriorly: trachea (medially) and prevertebral space (laterally) ⁸
• laterally: medial borders of both common carotid arteries (medial to levels III and IV)
• includes anterior jugular, pretracheal, paratracheal, prelaryngeal/precricoid (Delphian), and perithyroidal nodes

Termination

All the levels above eventually drain to the jugular trunk of their respective side and then to the right lymphatic duct or the thoracic duct (left) ¹⁰.

Variant anatomic boundaries

Minor variations to the above anatomic boundaries have been described.

For example, head and neck surgeons may use different intraoperative landmarks ^1,4: 

• levels IIa and IIb are separated by the vertical plane defined by the spinal accessory nerve
• the medial border of levels III and IV and lateral border of level VI is defined by the lateral border of the sternohyoid muscle
• the posterior border of levels II through IV and anterior border of level V may also be defined by the plane of sensory branches of the cervical plexus

In addition, radiologists may describe supraclavicular nodes separately from levels IV and V using the transverse level of the clavicle as the border ⁹.

Additional neck levels

The above classification is not inclusive of several important nodal groups in the head and neck:

• superior mediastinal nodes
• retropharyngeal nodes
• parotid nodes
• occipital nodes
• posterior auricular (mastoid) nodes
• facial nodes

Other classification systems include some of these regions, but a consensus approach has not been reached. For example, with respect to "level VII," radiologists may apply this label to superior mediastinal nodes ², radiation oncologists may apply this label to "prevertebral nodes" ³, and head and neck surgeons omit this level from their nomenclature altogether ¹. Thus, it is best to name lymph node groups outside of the established levels I-VI. If "level VII" is used for superior mediastinal lymph nodes, it should refer to the extension of the paratracheal chain below the suprasternal notch but above the level of the brachiocephalic artery ⁴.

See also

• cervical lymph node staging
• cervical lymph node groups