ENT (Otorhinolaryngology) · MU Sofia

30. Clinical anatomy of the larynx. Physiology of the larynx.

Covers the clinical anatomy of the larynx, starting with its nine cartilages and their key features, then the three laryngeal cavity regions with their boundaries and nerve supply, followed by the joints, extrinsic and intrinsic ligaments, and the intrinsic and extrinsic muscles with their innervation. The physiology section explains airway protection during swallowing and coughing, respiratory variation of the glottis, and phonation through the aerodynamic-myoelastic theory, including pitch and loudness control. Diagrams and a one-line summary of phonation are included.

Inside: 3 sections · 8 labelled pictures · 15 flashcards · 8 min

Topic 30 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 3 sections, about 1,119 words (8 min of reading), with 15 flashcards.

In this note

  1. Clinical anatomy of the larynx. Physiology of the larynx.
  2. I. Clinical Anatomy of the Larynx
  3. II. Physiology of the Larynx

I. Clinical Anatomy of the Larynx

The larynx is a hollow, fibrocartilaginous organ of the upper airway that:

Conducts air

Produces voice

Protects the lower respiratory tract during swallowing. C3-c6, Suspended from the hyoid bone

Continues inferiorly as the trachea

A. Laryngeal Framework (Cartilages) - nine cartilages (three single, three paired) connected by ligaments and membranes.

  • Thyroid (Single): Largest. Forms the Laryngeal Prominence ("Adam's Apple"). V-shaped lamina separated posteriorly. Superior and inferior horns.
  • Protects the anterior larynx. Its angle is sharper in males, leading to a deeper voice.
  • Cricoid (Single): Only complete ring in the airway ("Signet Ring" shape: narrow arch anteriorly, broad lamina posteriorly).
  • Marks the inferior limit of the larynx/pharynx (C6). Cricoid pressure (Sellick's maneuver) is applied here to prevent aspiration during intubation.
  • Epiglottis (Single): Leaf-shaped, attached to the inner surface of the thyroid cartilage.
  • Crucial for airway protection: folds down during swallowing.
  • Arytenoid (Paired): Pyramidal. Articulate on the superior border of the cricoid lamina. Contain the Vocal Process and Muscular Process.
  • Key for vocal fold movement; rotation allows adduction/abduction.
  • Corniculate (Paired): Small nodules articulating on the apices of the arytenoids.
  • Cuneiform (Paired): Small nodules suspended within the Aryepiglottic Folds.
  • Create small swellings visible during laryngoscopy.

B. Laryngeal Cavity (Internal Space) - lined with mucous membrane and divided into three sections by two sets of mucosal folds.

  • Supraglottis
  • Boundaries: (Vestibule): From the Laryngeal Inlet down to the Vestibular Folds (False Vocal Cords).
  • Key structures: Epiglottis, Aryepiglottic Folds, Vestibular Folds. False vocal cords
  • Innervation: Internal Branch of Superior Laryngeal Nerve (SLN).
  • Glottis:
  • Boundaries: The space between the Vestibular Folds and 1 cm below the Vocal Folds (True Vocal Cords).
  • Key structures: True Vocal Folds and the opening between them (Rima Glottidis). True vocal cords
  • Anterior & posterior commissures
  • Rima glottidis
  • Innervation: Internal Branch of SLN (above the cords) and Recurrent Laryngeal Nerve (RLN) (below the cords).
  • Subglottis:
  • Boundaries: the 1 cm boundary below the true vocal folds down to the inferior border of the cricoid cartilage. Narrowest part in children
  • Key structures: Trachea begins inferiorly.
  • Innervation: Recurrent Laryngeal Nerve (RLN).

C. Joints

  • Cricothyroid Joint: Rotation & gliding, Lengthens/tenses vocal cords. Controls pitch
  • Cricoarytenoid Joints: Rocking & sliding, Control width of rima glottidis Abd/add of vocal cords

D. Ligaments

Extrinsic Ligaments and Membranes - These anchor the larynx within the neck. THE LARYNX

  • Thyrohyoid Membrane: A wide, fibrous layer connecting the top of the thyroid cartilage to the hyoid bone.

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