Species Differences in Laryngeal Structure

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For information about general laryngeal structure see 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. The thyroarytenoid muscle is divided into 2 parts; the rostral and caudal vocalis, which are situated within the vocal folds and vestibular folds. The cuneiform processes are attached to the epiglottis.

Canine

The thyroarytenoid muscle is divided into 2 parts; the rostral and caudal vocalis, which are situated within the vocal folds and vestibular folds. There are laryngeal ventricles present.

Feline

Feline species have thick vocal folds. Purring occurs due to vibration of the vocal folds (and of the diaphragm) by rapid twitching of the laryngeal muscles. They have very sensitive mucosa, making intubation tricky.

Ruminants

The thyroid cartilage in ruminants is completely ventral. A small median ventricle is present in sheep and goats. There is a narrow glottic cleft, making intubation difficult. The larynx is close to the median retropharyngeal lymph node, so enlargement of the lymph nodes may compress the larynx as well as the pharynx.

Porcine

A small laryngeal ventricle is present and there are double corniculate process in the arytenoid cartilages. Stimulation of laryngeal mucosa can result in violent laryngeal spasms.

Avian

There are no vocal folds in avian species. Sound in the bird is produced in the syrinx. The larynx is on the hyoid apparatus. There are paired arytenoids, one constrictor and one dilator muscle only. There is no epiglottis.

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