During a neck dissection for oral cavity squamous cell carcinoma, the surgeon removes lymph nodes from levels I, II, and III. Which anatomical structure forms the posterior boundary of level II (upper jugular) lymph nodes?

• A Posterior border of the sternocleidomastoid muscle ✓
• B Posterior border of the submandibular gland
• C Posterior border of the internal jugular vein
• D Posterior belly of the digastric muscle

Explanation

Level II (upper jugular) lymph nodes extend from the skull base to the hyoid bone (or carotid bifurcation) and from the posterior border of the sternocleidomastoid muscle to the posterior border of the submandibular gland. The posterior boundary is the posterior border of the sternocleidomastoid muscle. The posterior belly of the digastric muscle forms the superior boundary, and the hyoid bone forms the inferior boundary.

Reference: Bailey and Love's Short Practice of Surgery, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.