PART 15 — LARYNX

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Study use: Rapid revision of laryngeal anatomy, intrinsic muscles and nerve supply, vocal-fold paralysis, pediatric stridor, benign vocal-fold lesions, laryngeal carcinoma, emergency cricothyrotomy, and tracheostomy emergencies. Management is intentionally concise and should be interpreted with airway stability, age, endoscopic findings, pathology, and functional severity.

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Priority Guide: 🔴 Core / Must Know | 🟠 Important | 🟡 Additional

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🎯 High-Yield Overview

• Posterior cricoarytenoid (PCA) = only vocal-fold abductor and classic safety muscle.
• Cricothyroid tenses/lengthens the vocal folds → high pitch → external branch of superior laryngeal nerve (EBSLN).
• All other intrinsic laryngeal muscles → recurrent laryngeal nerve (RLN).
• Internal superior laryngeal nerve → sensation above the cords; RLN → motor to most intrinsic muscles and sensation below the cords.
• Unilateral RLN palsy → hoarseness; bilateral near-midline palsy → stridor/airway obstruction.
• Laryngomalacia → infant inspiratory stridor + omega-shaped epiglottis; severe disease → supraglottoplasty.
• Croup → barking cough + hoarseness + stridor + steeple sign → dexamethasone ± nebulized epinephrine.
• Epiglottitis → high fever + drooling + tripod/muffled voice + thumb sign → airway first.
• Voice user + bilateral nodules → vocal nodules; smoker + deep husky voice → Reinke edema.
• Glottic SCC → early persistent hoarseness + sparse lymphatics; supraglottic cancer → earlier cervical nodes.
• Adult cannot-intubate/cannot-oxygenate emergency → cricothyrotomy through the cricothyroid membrane.

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RED FLAGS: Stridor with respiratory distress, cyanosis, drooling/inability to handle secretions, bilateral vocal-fold immobility, tumor-related airway obstruction, or a blocked/dislodged tracheostomy requires immediate airway management.

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1. LARYNGEAL ANATOMY, MEMBRANES & VOCAL-FOLD STRUCTURE

2. INTRINSIC MUSCLES & LARYNGEAL NERVES

3. VOCAL-FOLD PARALYSIS, STRIDOR & VOICE LOCALIZATION

4. PEDIATRIC STRIDOR — LARYNGOMALACIA, CROUP & EPIGLOTTITIS