. The anatomy of the horse, a dissection guide. Horses. 236 THE ANATOMY OF THE The Posterior Crico-abytenoid Muscle (Figs. 30 and 32). This is the most powerful of the intrinsic muscles. Its muscular tissue is dark red, and mixed with tendinous tissue. Its fibres take origin from the outer surface of the cricoid bezel, and are inserted into the prominent tubercle on the external angle of the arytenoid cartilage. Action — To swing out- wards the arytenoid carti- lage, and thus to separate the vocal cords and dilate the glottis. The Lateral Cbico-aey- TENOiD Muscle (Fig. 31). This muscle
. The anatomy of the horse, a dissection guide. Horses. 236 THE ANATOMY OF THE The Posterior Crico-abytenoid Muscle (Figs. 30 and 32). This is the most powerful of the intrinsic muscles. Its muscular tissue is dark red, and mixed with tendinous tissue. Its fibres take origin from the outer surface of the cricoid bezel, and are inserted into the prominent tubercle on the external angle of the arytenoid cartilage. Action — To swing out- wards the arytenoid carti- lage, and thus to separate the vocal cords and dilate the glottis. The Lateral Cbico-aey- TENOiD Muscle (Fig. 31). This muscle is placed below the thyro-arytenoid, under concealment of the thyroid wing. Its fibres arise from the upper border of the side of the cricoid cartilage; and, passing backwards and up- wards, they become inserted into the same tubercle on the base of the arytenoid as the posterior muscle, and into the outer surface of the arytenoid in front of that tubercle. Action.—The muscle acts on the crico-arytenoid joint in a manner antagonistic to the preceding muscle, approximating the vocal cords and narrowing the glottis by swinging the arytenoid cartilage in- wards. The Arytbnoidbus Muscle (Fig. 32). This may be regarded either as a single muscle, or as a double muscle whose right and left fibres meet at a median raphe. Its fibres are inserted on each side into the posterior surface of the arytenoid cartilage, and superiorly it is joined by the higher fibres of the thyro-arytenoid muscle. Action.—To approximate the right and left arytenoid cartilage, and thus narrow the glottis. Fig. 31. Larynx, Side View (thyroid ala removed). 1. Glossal Process of Hyoid ; 2. Cut Base of Thyroid Cormi; 3. Small Cornu ; 4. Great Cormi; 5. Epiglottis ; 6. Arytenoid Cartilage ; 7. Cut Wing of Thyroid Carti- lage ; 8. Facet on Cricoid for Articulation with Thyroid Cartilage; 9. Pouch of iVIucous Membrane from Ven- tricle of Larynx ; 10. and 11. Upper and Lower Bundles of Thyro-Arytenoideus ; 12. C
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecthorses, bookyear1902
