Species Differences in Laryngeal Structure

Larynx - Anatomy & Physiology

Equine

• Fusion of the two plates of the thyroid cartilage is incomplete forming a rostral pointing notch which is a good site for surgical entry into the larynx

• Thyroarytenoid muscle is divided into 2 parts- rostral and caudal vocalis which are situated within the vocal folds and vestibular folds

• Cuneiform processes attached to epiglottis

• Prominance (surgical landmark) rostral to opening in thyroid cartilage

Canine

• Thyroarytenoid muscle is divided into 2 parts- rostral and caudal vocalis which are situated within the vocal folds and vestibular folds

• Laryngeal ventricles present

Feline

• Thick vocal folds

• Purring due to vibration of vocal folds (and of the diaphragm) by rapid twitching of laryngeal muscles

• Very sensitive mucosa making intubation tricky

Ruminants

• Thyroid cartilage completely ventral

• Small median ventricle is present in sheep and goats

• Narrow glottic cleft making intubation difficult

• Close to the median retropharyngeal lymph node so enlargement of the lymph nodes may compress the larynx as well as the pharynx

Porcine

• Small laryngeal ventricle present

• Double corniculate process in arytenoid cartilages

• Stimulation of laryngeal mucosa can results in violent laryngeal spasm

Avian

• No vocal folds

• Sound in the bird is produced in the syrinx

• Larynx on hyoid apparatus

• Paired arytenoids, one constrictor and one dilator muscle only

• No epiglottis