label: Neck Lymph Node Boundary Sublevel IB
label_lc: neck lymph node boundary sublevel ib
description: "The following anatomical structures define the neck lymph node boundary for sublevel IB: Superior: body of the mandible; inferior: posterior belly of the digastric muscle; anterior (medial): anterior belly of the digastric muscle; posterior (lateral): stylohyoid muscle. (AJCC 8th ed.)"