During awake fiberoptic intubation, which nerve block provides anesthesia to the base of the tongue, epiglottis, and aryepiglottic folds?

Explanation

## Glossopharyngeal Nerve Block in Awake Fiberoptic Intubation **Key Point:** The glossopharyngeal nerve (CN IX) provides sensory innervation to the base of the tongue, epiglottis, aryepiglottic folds, and pharyngeal walls. Blocking this nerve is essential for preventing gag reflex and airway reflexes during AFI. ### Anatomy of Glossopharyngeal Nerve 1. **Sensory distribution**: - Base of tongue (posterior third) - Epiglottis - Aryepiglottic folds - Pharyngeal walls - Soft palate (minor contribution) 2. **Clinical significance in AFI**: - Prevents gag reflex during scope insertion - Reduces airway reactivity - Allows smooth passage of the endotracheal tube ### Technique of Glossopharyngeal Nerve Block - **Intraoral approach**: Palpate the soft palate and inject 2–3 mL of local anesthetic (1% lidocaine) lateral to the palatoglossal arch - **Landmark**: The tonsillar fossa and posterior pharyngeal wall - **Onset**: 3–5 minutes - **Bilateral block**: Required for complete airway anesthesia ### Comparison of Airway Nerve Blocks | Nerve | Innervates | Block Technique | Role in AFI | |-------|-----------|-----------------|-------------| | **Glossopharyngeal (CN IX)** | Base of tongue, epiglottis, aryepiglottic folds | Intraoral (tonsillar fossa) | **Essential — prevents gag** | | Superior laryngeal (SLN) | Larynx above vocal cords, epiglottis tip | External (thyroid notch) | Supplementary (laryngeal anesthesia) | | Recurrent laryngeal (RLN) | Larynx below vocal cords, trachea | Transtracheal injection | Supplementary (subglottic anesthesia) | | Vagal trunk | All above (diffuse) | Rare in AFI | Not standard | **High-Yield:** Glossopharyngeal nerve block is the most frequently tested nerve block for AFI in NEET PG. Candidates must know its sensory distribution (base of tongue, epiglottis, aryepiglottic folds) and that it prevents the gag reflex. **Mnemonic:** **GPN-AFI** = **G**losso**p**hary**n**geal for **A**wake **F**iberoptic **I**ntubation — the glossopharyngeal nerve is the primary target for preventing gag reflex. **Clinical Pearl:** A complete awake fiberoptic intubation typically requires a combination of: 1. Topical anesthesia (lidocaine 4% spray/gargle) 2. Glossopharyngeal nerve block (prevents gag) 3. Superior laryngeal nerve block (optional, for laryngeal anesthesia) 4. Transtracheal injection (optional, for subglottic anesthesia) **Warning:** ~~Recurrent laryngeal nerve block~~ does NOT prevent gag reflex because it innervates structures below the vocal cords. It is used only for subglottic anesthesia, not for gag suppression.