A patient presents with an 18-year-old male who has pericoronitis surrounding tooth #17. Plan is to refer to OMFS for definitive treatment. Which vital structure is at risk of damage during periosteal elevation for this procedure?

Correct answer: A. Lingual nerve

• A. CORRECT. The lingual nerve is at significant risk during periosteal elevation on the lingual aspect of the mandibular third molar region. The lingual nerve runs in close proximity to the lingual plate of the mandible in the region of tooth #17–18, and can be damaged during surgical flap elevation, leading to lingual paresthesia or anesthesia of the ipsilateral tongue, lingual gingiva, and floor of mouth.
• B. INCORRECT. The inferior alveolar nerve runs within the mandibular canal inferior to the third molar roots and is more at risk during the extraction itself (root proximity) rather than during periosteal elevation of the lingual flap.
• C. INCORRECT. The buccal nerve provides sensory innervation to the buccal mucosa and is located on the external (buccal) surface. It is not directly at risk during lingual periosteal elevation for lower third molar surgery.
• D. INCORRECT. The nerve to the mylohyoid branches from the inferior alveolar nerve before it enters the mandibular foramen and innervates the mylohyoid and anterior digastric muscles. While it is in the general area, the lingual nerve is more consistently reported as at risk during third molar surgery and periosteal elevation.