Immediately after an inferior alveolar nerve block, a patient cannot close the eyelid on the injected side and the corner of the mouth droops. Into which structure was the anesthetic most likely deposited?

Explanations

• Directing the needle too far posteriorly deposits anesthetic in the parotid gland, where branches of the facial nerve run, causing transient facial paralysis. Injection into the medial pterygoid muscle is associated with trismus, not facial paralysis.

  Source: Malamed, Handbook of Local Anesthesia — oneguy