Unpaired Cartilages
- Thyroid cartilage: Largest; “Adam’s apple.” Protects vocal cords. 📌 Clinical: Landmark for cricothyrotomy.
- Cricoid cartilage: Only complete ring; inferior boundary. 📌 Exam tip: Narrowest part of paediatric airway.
- Epiglottis: Leaf-shaped; covers laryngeal inlet on swallowing. 📌 Failure → aspiration risk.
Paired Cartilages
- Arytenoids: Control vocal fold movement/tension.
- Corniculates: Horn-shaped; sit on arytenoids.
- Cuneiforms: Support aryepiglottic folds.

🪢 Ligaments & Membranes

Extrinsic:
- Thyrohyoid membrane: Stabilises larynx to hyoid.
- Cricotracheal ligament: Connects cricoid → trachea.
Intrinsic:
- Quadrangular membrane: Upper boundary of ventricle.
- Cricothyroid ligament: Key in pitch control. 📌 Emergency airway access site.

🏛️ Internal Divisions of the Laryngeal Cavity

Supraglottis: Epiglottis + vestibular (false) cords.
Glottis: True cords + rima glottidis → sound production.
Subglottis: Below cords → cricoid border → trachea.

💪 Musculature

Intrinsic Muscles (fine control of cords)
- Cricothyroid: Tenses cords ↑ pitch (🎵). Nerve: external branch, SLN.
- Posterior cricoarytenoid: Only abductor → opens cords. 📌 Paralysis = stridor.
- Lateral cricoarytenoid & interarytenoids: Adduct cords → phonation.
- Thyroarytenoid (vocalis): Modulates mass/tension → tone quality.
Extrinsic Muscles (position larynx for swallowing/speech): e.g., thyrohyoid, sternohyoid, omohyoid.

🩸 Blood Supply & Innervation

Arteries:
- Superior laryngeal artery (from superior thyroid).
- Inferior laryngeal artery (from inferior thyroid).
Nerves:
- Superior laryngeal nerve (SLN): Internal = sensation supraglottis; External = motor → cricothyroid.
- Recurrent laryngeal nerve (RLN): Motor to all other intrinsic muscles; sensory to subglottis. 📌 Clinical: Unilateral RLN palsy = hoarse voice; bilateral = airway obstruction.

⚕️ Clinical Relevance

🗣️ Vocal cord paralysis: RLN injury (thyroid surgery, lung cancer). Hoarseness, aspiration, stridor.
🤧 Laryngitis: Inflammation → hoarse/absent voice.
🛠️ Airway procedures: Cricothyrotomy, intubation, tracheostomy → rely on landmarks.
🧪 Laryngeal cancer: Often presents with persistent hoarseness → needs early ENT referral.

📌 Key Exam Pearls

Posterior cricoarytenoid = only abductor.
RLN supplies all intrinsic muscles except cricothyroid.
Subglottic narrowing = paediatric airway obstruction site.
Glottis = main sound source for phonation.

✅ Conclusion

The larynx is a finely tuned organ balancing respiration, phonation, and protection. Understanding its cartilages, muscles, and nerve supply is essential for safe surgical practice, airway management, and recognising pathology.

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Anatomy of the Larynx

Introduction

🧱 Cartilaginous Framework