VAN 221: Veterinary Splanchnology and Applied Anatomy (1+1)

CAVITY OF LARYNX

• The cavity of the larynx is much smaller than one would naturally expect, from its external appearance. On looking into it through the pharyngeal end, narrow folds are seen, projecting from each lateral wall. These are the vocal folds
• The narrow part of the cavity between the vocal folds is the rima glottidis
• The cavity consists of three parts - the auditus laryngis, vestibule and the caudal compartment
• The auditus laryngis or pharyngeal aperture is a large, oblique, oval opening which faces into the ventral part of the pharynx
• It is bounded in front by the epiglottis above and behind by arytenoid cartilages and laterally by the aryepiglottic folds of mucous membrane, which stretch between the edges of the epiglottis and arytenoid cartilages.
• The vestibule of the larynx extends from the auditus laryngius to the vocal folds
• On its lateral walls are the very faint elevations covering the ventricular ligament and called the ventricular folds or false vocal cords
• Between the ventricular and vocal folds on each side is a very faint depression corresponding to the lateral ventricle of the horse
• The middle narrow part of the cavity is termed the glottis or rima glottis
• It is bounded on either side by the vocal folds and the medial faces of the arytenoid cartilages
• The vocal folds or true vocal cords are the fold of mucous membrane projecting from the lateral wall of the cavity of the larynx and are responsible for the production of voice
• The vocal folds covering the vocal ligaments. In ordinary breathing, the rima is lanceolate in form; when dilated, it is diamond shaped
• The widest part being between the vocal processes. The narrow part of the glottis between the vocal cords is termed the pars intermembranaecea, while the wider part between the arytenoid cartilages is the pars intercartilaginea.
• The caudal compartment of the laryngeal cavity is directly continuous with the trachea
• It is enclosed by the cricoid cartilage and the cricothyroid membrane. It is oval in form.
• The mucous membrane of the larynx is reflected around the margin of the auditus and become continuous with that of pharynx and is continuous behind with that which lines the trachea