THE LARYNX AND THE VOICE. 133 



3. The lateral crico-arytenoid stretches from the lateral 



portion of the upper edge of the cricoid, up- 

 ward and backward to the arytenoid cartilage. 

 Disarticulate the thyroid and cricoid of one 

 side, push aside the thyroid without injury to 

 the muscles, and this muscle can be readily 

 seen. Pull the muscle and note the result. 



4. The arytenoid muscle may be found by cutting 



away the tissue above the cricoid cartilage at 

 the back of the arytenoid cartilages. Cut 

 through the middle and also see where it is 

 attached to the arytenoid cartilages. Find 

 where the arytenoid cartilages articulate with 

 the cricoid. Pull the arytenoid muscle and 

 find its use. 



5. The thyro-arytenoid muscle extends from the ven- 



tral surface of the thyroid across to the aryte- 

 noid. Cut it at its origin, dissect it loose, 

 and prove its effect on the vocal cord. 



h. Sketch a dorsal, a ventral, and a lateral view of the 

 larynx. 



i. Carefully examine from the inside the muscles of 

 the opposite side, showing the effect of each on the vocal 

 cords. 



j. Remove all the muscles and find the exact shape of 

 the cartilages. 



k. Make a paper model of the cartilages of the larynx. 



