In the pterygomandibular space, what is the correct order of the following structures proceeding from MOST ANTERIOR to MOST POSTERIOR?

Correct answer: C. Lingual nerve → inferior alveolar nerve → inferior alveolar artery

• A. The artery is the most POSTERIOR of the three, not the middle structure.
• B. This places the inferior alveolar nerve anterior to the lingual nerve, reversing the true relationship. The lingual nerve is the anterior structure.
• C. CORRECT. Within the pterygomandibular space the sequence from anterior to posterior is lingual nerve, then inferior alveolar nerve, then inferior alveolar artery. The lingual nerve lies most anteriorly and medially — which is precisely why it is anaesthetised on withdrawal of the needle during an inferior alveolar block, and why it is the nerve most at risk during lingual retraction in third molar surgery.
• D. The artery does not lie between the two nerves. Both nerves lie anterior to the inferior alveolar artery.

Note: This ordering explains two clinical facts you already know. Depositing anaesthetic on withdrawal catches the lingual nerve because it sits anterior to the IAN. And positive aspiration during an IAN block usually means the inferior alveolar artery — the most posterior structure — which is exactly what the needle reaches if it is advanced too far.