Page:Laboratory Manual of the Anatomy of the Rat (Hunt 1924).djvu/79

Rh its wall — the thyroid, cricoid, and arytenoid cartilages. This may be done more easily under a dissecting microscope. The thyroid cartilage is a band extending around the anteroventral and lateral regions of the larynx. Each lateral extremity gives off an anterior and posterior horn, the latter joining the cricoid cartilage. The ventral portion of the cartilage bears a median notch on the anterior border, and is bound to the cricoid cartilage by the cricothyroid ligament. The cricoid cartilage has the shape of a signet ring, completely encircling the air passage. It is narrow ventrally, but expands dorsally into a hexagonal plate whose dorsal surface is concave. It is firmly united to the trachea by connective tissue. The arytenoids are a pair of small cartilages articulating with the anterior border of the dorsal plate of the cricoid. Each attaches to the dorsal end of a vocal cord.

Exercise XVIII. Draw and label the larynx.