Head and Neck ImagingLevel system of lymph node classification
nomenclature dividing the palpable
cervical lymph nodes into 7 regions or 'levels'; some
lymph nodes are not part of any of these levels, and are described by their anatomical location. Although this classification was deviced using surgical landmarks, translation into an imaging-based nodal classification is feasible (Table 1) (
Fig.1). A precise as possible application of this classification on
CT or MR studies considerably enhances the communication with the clinician on neck nodal disease.
Table 1. Imaging-based neck nodal classification (adapted from Som P.M, Curtin H.D., Mancuso A.A.: 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).
| Level I | Submental and submandibular nodes. |
| Level I A | Submental nodes, between the medial margins of the anterior bellies of the digastric muscles. |
| Level I B | Submandibular nodes, lateral to level I A nodes and anterior to the back of the submandibular salivary gland. |
| Level II | Upper internal jugular nodes, posterior to the back of the submandibular salivary gland, anterior to the back of the sternocleidomastoid muscle and above the level of the bottom of the body of the hyoid bone. |
| Level III | Middle jugular nodes, between the level of the bottom of the body of the hyoid bone and the level of the bottom of the cricoid arch, anterior to the back of the sternocleidomastoid muscle. |
| Level IV | Low jugular nodes, between the level of the bottom of the cricoid arch and the level of the clavicle, anterior to a line connecting the back of the sternocleidomastoid muscle and the posterolateral margin of the anterior scalene muscles; they are lateral to the carotid arteries. |
| Level V | Posterior triangle nodes, posterior to the back of the sternocleidomastoid muscle, and posterior to the line described in level IV. |
| Level V A | Above the level of the bottom of the cricoid arch. |
| Level V B | Between the level of the bottom of the cricoid arch and the level of the clavicle. |
| Level VI | Upper visceral nodes, between the carotid arteries from the level of the bottom of the body of the hyoid bone to the level of the top of the manubrium. |
| Level VII | Superior mediastinal nodes, between the carotid arteries below the level of the top of the manubrium and above the innominate vein. |
| Supraclavicular nodes | Nodes at, or caudal to, the level of the clavicle and lateral to the carotid artery. |
| Retropharyngeal nodes | Nodes behind the pharynx, medial to the internal carotid artery, from the skull base down to the level of the hyoid bone. |
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Diagram of the neck as seen from the left anterior view.
Left: the pertinent anatomy that relates to the nodal classification.
Right: an outline of the levels of the classification.
Note that the line of separation between levels I and II is the posterior margin of the submandibular gland. The separation between levels II and III and level V is the posterior edge of the sternocleidomastoid muscle. However, the line of separation between levels IV and V is an oblique line extending from the posterior edge of the sternocleidomastoid muscle to the posterolateral edge of the anterior scalene muscle. The posterior edge of the internal jugular vein separates level IIA and IIB nodes. The top of the manubrium separates levels VI and VII.
(From: Som P.M, Curtin H.D., Mancuso A.A.: 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, with permission).
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Level system of lymph node classification, Fig.1 | |