Which of the following is the correct sequence of anatomical structures encountered during oral endotracheal intubation?

Explanation

## Anatomical Sequence During Oral Endotracheal Intubation ### Normal Pathway During oral endotracheal intubation using direct laryngoscopy, the structures are encountered in the following order: 1. **Epiglottis** — the first major landmark visualized; the laryngoscope blade is used to lift it (directly or indirectly) to expose the glottic opening 2. **Vocal cords** — the true vocal cords (glottis) are the critical landmark; the endotracheal tube is advanced *between* them under direct vision 3. **Arytenoid cartilages** — paired pyramidal cartilages at the posterior aspect of the larynx; they are seen *posterior* to the vocal cords and mark the posterior boundary of the glottis; the tube tip passes anterior to them as it enters the trachea 4. **Trachea** — the final resting position; the cuff is inflated just below the vocal cords, above the carina **Key Point:** The correct sequence is **Epiglottis → Vocal cords → Arytenoid cartilages → Trachea** (Option C). The vocal cords are encountered *before* the arytenoid cartilages because the arytenoids are the posterior anchoring structures of the cords — the tube passes between the cords first, then moves past the arytenoids into the trachea. **High-Yield:** Option A (Epiglottis → Arytenoid → Vocal cords → Trachea) is anatomically incorrect because it places the arytenoid cartilages *anterior* to the vocal cords in the intubation path, which contradicts laryngeal anatomy. The arytenoids are the posterior attachment points of the vocal cords; the tube traverses the glottic opening (between the cords) before passing the arytenoid level into the trachea. *(Miller's Anesthesia, 8th ed.; Morgan & Mikhail's Clinical Anesthesiology)* ### Clinical Relevance - Failure to elevate the epiglottis results in esophageal intubation - The vocal cords are the primary confirmation landmark — the tube must be seen passing *between* them - Capnography and bilateral chest auscultation confirm correct tracheal placement **Clinical Pearl:** On laryngoscopy, the arytenoid cartilages appear as paired "pyramidal" structures at the posterior glottis. They are visualized *after* the vocal cords come into view, confirming the correct anatomical sequence: Epiglottis → Vocal cords → Arytenoids → Trachea.