Structures of the Larynx

Structures of the Larynx

Visceral Compartment of the Neck

Osteology of the Larynx

Thyroid and Cricoid Cartilages:

  • Thyroid cartilage:
    • Features include the right lamina, left lamina, superior horn, inferior horn, superior thyroid notch, superior thyroid tubercle, laryngeal prominence (Adam's apple), oblique line, inferior thyroid notch, and facets for articulation with the cricoid cartilage.
  • Cricoid cartilage:
    • Features include the lamina and the arch, with facets for articulation with the inferior horn of the thyroid cartilage and arytenoid cartilage.

Extrinsic Ligaments of the Larynx

  • Hyo-epiglottic ligament:
  • Lateral thyrohyoid ligaments: (containing the triticeal cartilage and aperture for the internal branch of the superior laryngeal nerve and associated artery)
  • Thyrohyoid membrane:
  • Median thyrohyoid ligament:
  • Cricothyroid ligament: (a safe place for airway placement below vocal cords during emergencies)
  • Cricotracheal ligament:

Osteology of Larynx: Epiglottis, Arytenoid, and Corniculate Cartilages

  • Epiglottis:
    • Posterior and anterior surfaces, connected via the hyo-epiglottic ligament.
  • Arytenoid cartilage:
    • Features include the apex, articular facet for corniculate cartilage, anterolateral surface, medial surface, ridge for attachment of vestibular ligament, and depression for attachment of vocalis muscles.
  • Corniculate cartilage:
    • Positioned atop arytenoid cartilages.

Internal Features of the Larynx

  • Laryngeal Inlet:
  • Vestibule:
  • Vestibular folds: (false vocal cords)
  • Vocal folds: (true vocal cords)
  • Rima glottidis: (opening between vocal cords)
  • Infraglottic space:
  • Piriform recess:
  • Laryngeal Ventricle:

Intrinsic Muscles of the Larynx (Innervated by CN X)

  • Thyroarytenoid: Adduction (inferior laryngeal nerve)
  • Lateral cricoarytenoid: Adduction (inferior laryngeal nerve)
  • Posterior cricoarytenoid: Abduction (inferior laryngeal nerve)
  • Transverse arytenoids: Adduction
  • Oblique arytenoids: Adduction
  • Cricothyroid: Tightens vocal cords (external branch of the superior laryngeal nerve)

Arterial Supply of the Larynx

  • Superior laryngeal artery: from the superior thyroid artery (branch of the external carotid artery)
  • Inferior laryngeal artery: from the inferior thyroid artery (branch of the thyrocervical trunk from the subclavian artery)

Nerve Supply of the Larynx

  • Superior laryngeal nerve:
    • Internal branch: Sensory above the vocal cords
    • External branch: Motor to the cricothyroid muscle
  • Inferior laryngeal nerve: (continuation of the recurrent laryngeal nerve)
    • Provides motor innervation to all intrinsic muscles of the larynx except the cricothyroid and sensory below the vocal cords

Clinical Correlates

  • Cut external laryngeal nerve: Loss of function in the cricothyroid muscle resulting in voice changes.
  • Unilateral recurrent laryngeal nerve section: Hoarseness due to paralysis of one vocal cord.
  • Bilateral recurrent laryngeal nerve section: Severe airway obstruction due to paralysis of both vocal cords.