Laryngeal Anatomy and Innervation
The larynx acts as a protective sphincter for the airway and is the organ of phonation. It is composed of cartilages, membranes, and intrinsic muscles.
| Structure | Key Characteristics |
|---|---|
| Cartilages | Thyroid, cricoid, and epiglottis (unpaired); arytenoid, corniculate, and cuneiform (paired). |
| Posterior Cricoarytenoid | Only muscle that abducts the vocal cords (opens the glottis). |
| Lateral Cricoarytenoid | Adducts the vocal cords (closes the glottis). |
Innervation (Vagus Nerve – CN X):
- Superior Laryngeal Nerve (Internal branch): Provides sensory above the vocal cords.
- Superior Laryngeal Nerve (External branch): Provides motor to the cricothyroid muscle (tenses vocal cords).
- Recurrent Laryngeal Nerve: Provides sensory below the vocal cords and motor to all other intrinsic laryngeal muscles.