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Haematoma After IANB — ORE Part 1 MCQ

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ModerateOral SurgeryHaematoma After IANBORE Part 1

During an inferior alveolar nerve block, a patient immediately develops a haematoma in the pterygomandibular region. Which vascular structure has most likely been injured?

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Correct answer: A — Pterygoid venous plexus

The pterygoid venous plexus is the most likely source. It lies posterior and superior to the mandibular foramen, close to the needle path and local-anaesthetic deposition site for an inferior alveolar nerve block; injury can therefore produce an immediate deep haematoma. The inferior alveolar artery and vein are also nearby, but the plexus is the classic vascular structure specifically associated with haematoma risk during this technique. The internal carotid artery and external jugular vein are remote from the intraoral injection field. The facial and lingual arteries are important regional vessels but are not the characteristic vessel at risk in a pterygomandibular haematoma following a conventional IANB.

Reference: StatPearls Publishing. Inferior Alveolar Nerve Block, updated 2026. https://pubmed.ncbi.nlm.nih.gov/33232038/