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TEXT-BOOK OF PHYSIOLOGY. 



directed backward and inward. The base presents three angles an ante- 

 rior, an external, and an internal. The anterior angle is long and pointed 

 and projects forward in a horizontal plane. It serves for the attach- 

 ment of the vocal membranes and is therefore termed the vocal process. 

 The external angle is short, rounded, and prominent, and serves for the 

 attachment of muscles. The internal angle affords a point of insertion for a 

 ligament. The inferior surface of the arytenoid is concave for articulation 

 with the convex surface of the cricoid facet. Its long axis, however, is 

 directed from before backward and almost at right angles to the long axis of 

 the cricoid facet. 



FIG. 286. FIG. 287. 



FIG. 286. LARYNGEAL CARTILAGES AND LIGAMENTS, ANTERIOR SURFACE, i. Hyoid bone. 

 2, 2, 3, 3. Greater and lesser cornua. 4. Thyroid cartilage. 5. Thyro-hyoid membrane. 6. 

 Thyro-hyoid ligaments. 7. Cartilaginous nodule. 8. Cricoid cartilage. 9. The crico-thyroid 

 membrane. 10. The crico-thyroid ligaments, n. Trachea. (Sappey.) 



FIG. 287. LARYNGEAL CARTILAGES AND LIGAMENTS, POSTERIOR SURFACE, i, i. Thyroid 

 cartilage. 2. Cricoid cartilage. 3, 3. Arytenoid cartilages. 4, 4. Crico-arytenoid articulations. 

 5,5. Crico-thyroid articulations. 6. Union of the cricoid cartilage and of the trachea. 7. Epiglot- 

 tis. 8. Ligament uniting it to the reentering angle of the thyroid cartilage. (Sappey.) 



The cornicula laryngis and the cuneiform cartilages are small nodules of 

 yellow elastic cartilage embedded in a fold of membrane which unites the 

 arytenoid and the epiglottis. They are fragments of a ring of cartilage which 

 in some animals e.g., ant-eater extends between these two cartilages. 



The crico-thyroid articulation is formed by the opposition of the tip of the 

 inferior cornu of the thyroid cartilage and an articular facet on the side of the 

 cricoid. The joint is provided with a synovial membrane and enclosed by a 

 capsular ligament. The movements permitted at this joint take place 

 around a horizontal axis and consist of an upward and downward movement 



