Table 8.1.

Cervical LN level classification according to the AAO-HNS

Level	Area	Sublevels	Areas drained
I	Submental LNs Submandibular LNs	IA IB	Floor of mouth, anterior oral tongue, anterior mandibular alveolar ridge, and lower lip Oral cavity, anterior nasal cavity, midface soft tissue structures, submandibular gland
II	Upper internal jugular nodes; lying between the skull base and the hyoid bone	IIA, IIB	Oral cavity, nasal cavity, nasopharynx, oropharynx, hypopharynx, larynx, and parotid gland
III	Middle internal jugular nodes; lying between the hyoid bone and cricoid cartilage		Oral cavity, nasopharynx, oropharynx, hypopharynx, and larynx
IV	Lower internal jugular nodes; extending between cricoid cartilage and the clavicle		The hypopharynx, cervical esophagus, and larynx
V	Posterior triangle (spinal accessory chain) LNs	VA VB	VA: nasopharynx and oropharynx VB: thyroid gland
VI	Pretracheal + prelaryngeal + paratracheal LNs		Thyroid gland, glottic and subglottic larynx, apex of piriform sinus, cervical esophagus
VII	Upper mediastinal LNs