fig1

Figure 1. Assigned lymph node levels of the lateral neck. Level IA: Submental nodes. Level IB: Submandibular nodes. Level IIA: Upper jugular nodes anterior to the spinal accessory nerve. Level IIB: Upper jugular nodes posterior to the spinal accessory nerve. Level III: Mid jugular nodes. Level IV: Lower jugular nodes. Level VA: Posterior triangle nodes superior to the level of the inferior border of cricoid cartilage. Level VB: Posterior triangle nodes inferior to the level of the inferior border of cricoid cartilage. Level VI: Central compartment nodes.