Canis ISSN: 2398-2942

Larynx: miscellaneous conditions

Contributor(s): Andrew Gardiner, Geraldine Hunt, Jill Sammarco, Gert ter Haar

Basic structure of the larynx

  • Cartilaginous, muscular and ligamentous components.
  • Suspended and supported by hyoid apparatus.
  • Rima glottidis is the cranial opening of larynx and the narrowest part.
  • Function is to protect trachea by establishing cough and close the rima glottidis during swallowing and to produce voice.

Cartilaginous components

  • Epiglottis: leaf-shaped; forms cranial border of larynx.
  • Thyroid: shield-shaped; forms ventral and lateral borders.
  • Cricoid: ring-shaped, wider dorsally; forms dorsocaudal border.
  • Arytenoids: paired, with corniculate (dorsal) and cuneiform (ventral) processes at the laryngeal entrance.

Innervation - the vagus nerve

  • Vagus nerve branches:
    • Cranial laryngeal nerve supplies cricothyroid muscle and laryngeal mucosa.
    • Recurrent laryngeal nerve forms the caudal laryngeal nerve and supplies the other intrinsic laryngeal muscles.
  • Sensory nerve branches supply the laryngeal mucosa.

Muscles

  • The intrinsic muscles of the larynx determine the diameter of the rima glottis by their actions of abduction or adduction of the laryngeal cartilages.
  • The most important laryngeal muscles:
    • Cricoarytenoideus dorsalis: main abductor.
    • Thyroarytenoideus: main adductor.

Blood supply

  • Cranial laryngeal artery (branch of external carotid) courses alongside the cranial laryngeal nerve.

Lymphatics

  • Drainage to retropharyngeal lymph node.
    Review the anatomy of the larynx prior to any surgical procedure.

Other

Summary of canine laryngeal disorders

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Rutherford L, Beever L, Bruce M M, Haar ter G (2017) Assessment of computed tomography derived cricoid cartilage and tracheal dimensions to evaluate degree of cricoid narrowing in brachycephalic dogs. Vet Radiol Ultrasound 58 (6), 634-646 PubMed.
  • Oechtering G U, Pohl S, Schlueter C, Lippert J P, Alef M, Kiefer I et al (2016) A Novel Approach to Brachycephalic Syndrome. 1. Evaluation of Anatomical Intranasal Airway Obstruction. Vet Surg 45(2), 165-172 PubMed.
  • Oechtering G U, Pohl S, Schlueter C, Schuenemann R (2016) A Novel Approach to Brachycephalic Syndrome. 2. Laser-Assisted Turbinectomy (LATE). Vet Surg 45(2), 173-181 PubMed.
  • Haimel G, Dupr√© G (2015) Brachycephalic airway syndrome: a comparative study between pugs and French bulldogs. JSAP 56(12), 714-719 PubMed.
  • Gabriel A, Poncelet L, Van Ham L, Clercx C, Braund KG, Bhatti S et al (2006) Laryngeal paralysis-polyneuropathy complex in young related Pyrenean mountain dogs. JSAP 47(3), 144-149 PubMed.
  • Snelling S R, Edwards G A (2003) A retrospective study of unilateral arytenoid lateralisation in the treatment of laryngeal paralysis in 100 dogs (1992-2000). Aust Vet J 81(8), 464-468 PubMed.

Other sources of information

  • Haar ter G (2016) Throat Anatomy and Physiology. In: Harvey RG, Haar ter G (eds) Ear, Nose and Throat Diseases of the Dog and Cat. 1st edn. London: CRC Press, Taylor & Francis Group; pp. 345–56.
  • Haar ter G (2016) Surgery of the Throat. In: Harvey RG, Haar ter G (eds) Ear, Nose and Throat Diseases of the Dog and Cat. 1st edn. London: CRC Press, Taylor & Francis Group; pp. 475–90.
  • Venker-van Haagen A J (2000) Diseases of the throat. In: Textbook of Veterinary Internal Medicine. 5th edn. Eds S J Ettinger & E C Feldman. Philadelphia: W B Saunders. pp 1029-1031.


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