Anterior to a traverse line drawn through the posterior edge of the SMG
Boundaries of Level IA nodes:
Between medial margins of anterior bellies of the digastric muscles
(Former name: Submental nodes)
Boundaries of Level IB nodes:
Posterior and lateral the medial edge of the anterior belly of the digastric muscle
Anterior to the posterior edge of the SMG
(Former name: Submandibular nodes)
Boundaries of Level II nodes:
From skull base to the lower body of the hyoid bone
Anterior to the posterior edge of of the SCM
Posterior to the posterior edge of the SMG
Boundaries of Level IIA nodes:
Anterior, lateral, or medial to the IJV
OR lie posterior to the IJV and are inseparable from it
(Former name: Upper internal jugular nodes)
Boundaries of Level IIB nodes:
Lie posterior to the IJV and have a fat plane separating the nodes and the vein
(Former name: Upper spinal accessory nodes)
Boundaries of Level III nodes:
Between the lower body of the hyoid bone and the lower margin of the cricoid arch
Anterior to the posterior edge of the SCM
Lateral to the medial margin of the CCA/ICA
(Former name: Mid-jugular nodes)
Boundaries of Level IV nodes:
Between the lower margin of the cricoid cartilage arch and the level of the clavicle
Anterior and medial to an oblique line drawn between the posterior edge of the SCM and the posterolateral edge of the anterior scalene muscle
Lateral to the medial margin of the CCA
(Former name: Low jugular nodes)
Boundaries of Level V nodes:
From the skull base at the posterior border of the attachment of the SCM to the clavicle
Anterior to the anterior edge of the trapezius muscle
Posterior to the posterior edge of the SCM (skull base to bottom of cricoid)
OR posterior and lateral to an oblique line through the posterior edge of the SCM and the posterolateral edge of the anterior scalene muscle (bottom of cricoid to clavicle)
Boundaries of Level VA nodes:
From skull base superiorly to lower margin of cricoid cartilage inferiorly
(Former name: Upper posterior cervical nodes)
Boundaries of Level VB nodes:
From lower margin of cricoid cartilage to level of clavicle
(Former name: Lower posterior cervical nodes)
Boundaries of Level VI nodes:
Inferior to the body of hyoid, superior to the top of manubrium
Between the medial margins of the ICAs/CCAs
(Former name: Visceral nodes)
Boundaries of Level VII nodes:
Caudal to the top of the manubrium in the superior mediastinum
Between the medial margins of the left and right common carotid arteries