Ongoing numbness of the anterior 2/3 of tongue is caused by which nerve being anesthetized?

Ongoing numbness of the anterior 2/3 of tongue is caused by which nerve being anesthetized?

• A. Lingual nerve
• B. Glossopharyngeal nerve
• C. Facial nerve
• D. Hypoglossal nerve

Answer: (A)

The front two-thirds of the tongue receive general sensory information from the lingual nerve, a branch of the mandibular division of the trigeminal nerve. If this nerve is anesthetized, the patient experiences numbness in that region because the fibers that detect touch, temperature, and pain are blocked. The glossopharyngeal nerve supplies the posterior one-third of the tongue, so it wouldn’t account for numbness in the anterior portion. The hypoglossal nerve controls tongue movement, not sensation, so blocking it would cause weakness rather than numbness. The facial nerve mainly provides motor innervation to facial muscles and carries taste fibers to the anterior two-thirds via the chorda tympani; it is not the primary carrier of the general sensory sensation for that area, so its anesthesia wouldn’t produce the same numbness pattern.

The front two-thirds of the tongue receive general sensory information from the lingual nerve, a branch of the mandibular division of the trigeminal nerve. If this nerve is anesthetized, the patient experiences numbness in that region because the fibers that detect touch, temperature, and pain are blocked. The glossopharyngeal nerve supplies the posterior one-third of the tongue, so it wouldn’t account for numbness in the anterior portion. The hypoglossal nerve controls tongue movement, not sensation, so blocking it would cause weakness rather than numbness. The facial nerve mainly provides motor innervation to facial muscles and carries taste fibers to the anterior two-thirds via the chorda tympani; it is not the primary carrier of the general sensory sensation for that area, so its anesthesia wouldn’t produce the same numbness pattern.