Neck Lymph Node Boundary Sublevel IIB

**Semantic type:** Finding

**Definition:** The following anatomical structures define the neck lymph node boundary for sublevel IIB: Superior: skull base; inferior: horizontal plane defined by the inferior body of the hyoid bone; anterior (medial): vertical plane defined by the spinal accessory nerve; posterior (lateral): lateral border of the sternocleidomastoid muscle. (AJCC 8th ed.)