Pharyngeal and Laryngeal Function

• The pharynx and larynx are innervated by:
  • CN IX - the glossopharyngeal nerve
  • CN X - the vagus nerve
  • CN XI - the accessory nerve
• Pharyngeal and laryngeal function is best studied by:
  1. Observing the horse eat and swallow
  2. Endoscopy

Laryngeal Dysfunction

• Left recurrent laryngeal hemiplegia is the most common dysfunction in horses.
  • The left recurrent laryngeal nerve is a branch of the vagus nerve.
  • Horses are known as "roarers".

Pharyngeal Dysfunction

• Pharyngeal paralysis in horses is commonly associated with peripheral disease.
  • Especially guttural pouch disease.
    • Endoscopy of the guttural pouches should be therefore be performed in horses that are dysphagic.