Emergency Medicine Exam 1 Practice

The main idea is the distribution of facial sensory nerves. The mental nerve, a terminal branch of the inferior alveolar nerve from the mandibular division of the trigeminal nerve, provides sensation to the chin and lower lip. It exits at the mental foramen near the premolars, so targeted anesthesia for the mental region is achieved by blocking this nerve.

That’s why this option is best: it directly matches the sensory area being anesthetized. The other nerves supply different regions—infraorbital covers the midface (lower eyelid, side of the nose, upper lip), while supratrochlear and supraorbital are branches of the ophthalmic division supplying the forehead and scalp.