A patient undergoes selective neck dissection (SND) levels I–III for an oral tongue SCC with clinically N0 neck. Which nerve is at greatest risk of injury during dissection of level IIb (submuscular recess)?

• A Hypoglossal nerve
• B Lingual nerve
• C Marginal mandibular branch of facial nerve
• D Spinal accessory nerve (CN XI) ✓

Explanation

Level IIb (posterior triangle above the spinal accessory nerve / submuscular recess) places the spinal accessory nerve at greatest risk because level IIb nodes lie posterior and superior to this nerve. Injury results in shoulder syndrome — trapezius weakness, shoulder droop, and pain. The hypoglossal nerve is at risk at level I/IIA, the marginal mandibular branch at the mandibular margin during level I clearance, and the lingual nerve during submandibular gland dissection.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.