Inferior Alveolar Nerve Injury — ORE Part 1 MCQ

Correct answer: D — Inferior alveolar nerve

The correct answer is D (Inferior Alveolar Nerve). The inferior alveolar nerve is the only structure that runs within the inferior alveolar canal. When third molar roots are in close proximity to this canal—particularly in mesioangular impactions which are most closely positioned to the canal—the inferior alveolar nerve is at direct risk of injury from surgical instruments, root displacement, or compression. Injury may manifest as paresthesia or hypoaesthesia of the lower lip, chin, and anterior mandibular tissues. While the lingual nerve is also at risk during third molar extraction (affecting taste and sensation to the anterior two-thirds of the tongue), it is threatened primarily by retraction and tissue trauma during flap reflection, not by root proximity to the IAN canal itself. The mental nerve (terminal branch of IAN), mylohyoid nerve (motor branch), and buccal nerve are not significantly at risk from this specific anatomical scenario. This Easy question tests straightforward surgical anatomy and discrimination based on the stem's explicit mention of proximity to the inferior alveolar nerve canal.

Reference: Inferior alveolar nerve injury after mandibular third molar extraction: a literature review. PubMed. 2014. https://pubmed.ncbi.nlm.nih.gov/25635208/ and West of Scotland Oral Surgery Research Group study. 1992. https://pubmed.ncbi.nlm.nih.gov/1567807/