Definition of Regional Lymph Nodes

Question 1

cNx

Answer 1

Regional lymph nodes cannot be assessed

Question 2

cN0

Answer 2

No regional lymph node metastasis

Question 3

cN1

Answer 3

Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(-)

Question 4

cN2

Answer 4

Metastasis in a single ipsilateral lymph node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-) or metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-) or in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, ENE(-)

Question 5

cN2a

Answer 5

Metastasis in single ipsilateral or contralateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-)

Question 6

cN2b

Answer 6

Metastasis in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(-)

Question 7

cN2c

Answer 7

Metastasis in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-)

Question 8

cN3

Answer 8

Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(-); or metastasis in a single ipsilateral node ENE(+) or multiple ipsilateral, contralateral, or bilateral nodes, any with ENE(+)

Question 9

cN3a

Answer 9

Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(- )

Question 10

cN3b

Answer 10

Metastasis in a single ipsilateral node ENE(+) or multiple ipsilateral, contralateral, or bilateral nodes, any with ENE(+)

Question 11

pNx

Answer 11

Regional lymph nodes cannot be assessed

Question 12

pN0

Answer 12

No regional lymph node metastasis

Question 13

pN1

Answer 13

Metastasis in a single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(-)

Question 14

pN2

Answer 14

Metastasis in a single ipsilateral or contra lateral ymph node, 3 cm or smaller in greatest dimension and ENE(+); or larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(- ); — N2a or metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-); — N2b or in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, ENE(-) — N2c

Question 15

pN3

Answer 15

Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(-) — N3a or metastasis in a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+) or multiple ipsilateral, contralateral, or bilateral nodes, any with ENE(+) — N3b

Question 16

pN3a

Answer 16

Metastasis in a lymph node larger than 6 cm in greatest dimension and ENE(-)

Question 17

pN3b

Answer 17

Metastasis in a single ipsilateral node larger than 3 cm in greatest dimension and ENE(+) or multiple ipsilateral, contralateral, or bilateral nodes, any with ENE(+)

Question 18

Level IA boundaries

Answer 18

Superior: symphysis of mandible

Inferior: body of hyoid

Anterior (medial): anterior belly of contralateral digastric

Posterior (lateral): anterior belly of the ipsilateral digastric

Question 19

Level IB boundaries

Answer 19

Superior: body of the mandible

Inferior: posterior belly of the digastric

Anterior (medial): anterior belly of the digastric

Posterior (lateral): stylohyoid m.

Question 20

Level IIA boundaries

Answer 20

Superior: skull base

Inferior: horizontal plane defined by the inferior border of the hyoid

Anterior (medial): stylohyoid

Posterior (lateral): vertical plane defined the spinal accessory nerve

Question 21

Level IIB boundaries

Answer 21

Superior: skull base

Inferior: horizontal plane defined by the inferior border of the hyoid bone

Anterior (medial): vertical plane defined by the spinal accessory nerve

Posterior (lateral): lateral border of the SCM

Question 22

Level III boundaries

Answer 22

Superior: horizontal plane defined by the inferior border of the hyoid

Inferior: horizontal plane defined by the lower border of the cricoid cartilage

Anterior (medial): lateral border of SCM

Posterior (lateral): lateral border of SCM or sensory branches of the cervical plexus

Question 23

Level IV boundaries

Answer 23

Superior: horizontal plane defined by the inferior border of the cricoid cartilage

Inferior: clavicle

Anterior (medial): lateral border of SCM

Posterior (lateral): lateral border of SCM or sensory branches of the cervical plexus

Question 24

Level VA boundaries

Answer 24

Superior: apex of the convergence of SCM and trapezius

Inferior: horizontal plane defined by the lower border of the cricoid cartilage

Anterior (medial): posterior border of SCM or sensory branches of the cervical plexus

Posterior (lateral): anterior border of trapezius

Question 25

Level VB boundaries

Answer 25

Superior: horizontal plane defined by the lower border of the cricoid cartilage Inferior: clavicle Anterior (medial): posterior border of SCM Posterior (lateral): anterior border of trapezius

Question 26

Level VI boundaries

Answer 26

Superior: hyoid bone Inferior: suprasternal notch Anterior (medial): common carotid artery Posterior (lateral): common carotid artery

Question 27

Level VII boundaries

Answer 27

Superior: suprasternal notch Inferior: innominate artery Anterior (medial): sternum Posterior (lateral): trachea, esophagus, and prevertebral fascia

Question 28

Submental lymph nodes (sublevel IA)

Answer 28

Lymph nodes within the triangular boundary of the anterior belly of the digastric muscles and the hyoid bone. These nodes are at greatest risk for harboring metastases from cancers arising from the floor of mouth, anterior oral tongue, anterior mandibular alveolar ridge, and lower lip.

Question 29

Submandibular lymph nodes (sublevel IB)

Answer 29

Lymph nodes within the boundaries of the anterior and posterior bellies of the digastric muscle, the stylohyoid muscle, and the body of the mandible. These include the preglandular and the postglandular nodes and the prevascular and postvascular nodes. The submandibular gland is included in the specimen when the lymph nodes within the triangle are removed. These nodes are at greatest risk for harboring metastases from cancers arising from the oral cavity, anterior nasal cavity, skin, and soft tissue structures of the midface, as well as from the submandibular gland.

Question 30

Upper jugular lymph nodes (level IIA and IIB)

Answer 30

Lymph nodes located around the upper third of the internal jugular vein and adjacent spinal accessory nerve, extending from the level of the skull base (above) to the level of the inferior border of the hyoid bone (below). The anterior (medial) boundary is stylohyoid muscle (the radiologic correlate is the vertical plane defined by the posterior surface of the submandibular gland) and the posterior (lateral) boundary is the posterior border of the stemocleidomastoid muscle. Sublevel IlA nodes are located anterior (medial) to the vertical plane defined by the spinal accessory nerve. Sublevel IlB nodes are located posterior lateral to the vertical plane defined by the spinal accessory nerve. (The radiologic correlate is the lateral border of the internal jugular on a contrast-enhanced CT scan.) The upper jugular nodes are at greatest risk for harboring metastases from cancers arising from the oral cavity, nasal cavity, nasopharynx, oropharynx, hypopharynx, larynx, and parotid gland.

Question 31

Middle jugular lymph nodes (level III)

Answer 31

Lymph nodes located around the middle third of the internal jugular vein, extending from the inferior border of the hyoid bone (above) to the inferior border of the cricoid cartilage (below). The anterior (medial) boundary is the lateral border of the sternohyoid muscle, and the posterior (lateral) boundary is the posterior border of the sternocleidomastoid muscle. These nodes are at greatest risk for harboring metastases from cancers arising from the oral cavity, nasopharynx, oropharynx, hypopharynx, and larynx.

Question 32

Lower jugular lymph nodes (level IV)

Answer 32

Lymph nodes located around the lower third of the internal jugular vein, extending from the inferior border of the cricoid cartilage (above) to the clavicle below. The anterior (medial) boundary is the lateral border of the sternohyoid muscle and the posterior (lateral) boundary is the posterior border of the stemocleidomastoid muscle. These nodes are at greatest risk for harboring metastases from cancers arising from the hypopharynx, thyroid, cervical esophagus, and larynx.

Question 33

Posterior triangle lymph nodes (sublevels VA and VB)

Answer 33

This group is composed predominantly of the lymph nodes located along the lower half of the spinal accessory nerve and the transverse cervical artery. The supraclavicular nodes also are included in the posterior triangle group. The superior boundary is the apex formed by the convergence of the stemocleidomastoid and trapezius muscles; the inferior boundary is the clavicle; the anterior (medial) boundary is the posterior border of the stemocleidomastoid muscle; and the posterior (lateral) boundary is the anterior border of the trapezius muscle. Thus, sublevel VA includes the spinal accessory nodes, whereas sublevel VB includes the nodes following the transverse cervical vessels and the supraclavicular nodes, with the exception of the Virchow node, which is located in level N . The posterior triangle nodes are at greatest risk for harboring metastases from cancers arising from the nasopharynx, oropharynx, and cutaneous structures of the posterior scalp and neck.

Question 34

Anterior compartment lymph nodes (level VI)

Answer 34

Lymph nodes in this compartment include the pretracheal and paratracheal nodes, precrjcoid (Delphian) node, and the perithyroidal nodes, including the lymph nodes along the recurrent laryngeal nerves. The superior boundary is the hyoid bone; the inferior boundary is the suprasternal notch; and the lateral boundaries are the common carotid arteries. These nodes are at greatest risk for harboring metastases from cancers arising from the thyroid gland, glottic and subglottic larynx, apex of the piriforrn sinus, and cervical esophagus.

Question 35

Superior mediastinal lymph nodes (level VII)

Answer 35

Lymph nodes in this group include pretracheal, paratracheal, and esophageal groove lymph nodes, extending from the level of the suprastemal notch cephalad and up to the innominate artery caudad. These nodes are at greatest risk of involvement by thyroid cancer and cancer of the esophagus.