VESSELS AND NERVES OP LARYNX. 



777 



termed the arytenoid glands. They exist also in large numbers upon the inner 

 surface of the sacculus laryngis. None are found on the vocal cords. 



Vessels and Nerves. The arteries of the larynx are the laryngeal branches 

 derived from the superior and inferior thyroid. The veins empty themselves 

 into the superior, middle, and inferior thyroid veins. The lymphatics terminate 

 in the deep cervical glands. The nerves are the superior laryngeal, and the in- 

 ferior or recurrent laryngeal branches of the pneumogastric nerves, joined by 

 filaments from the sympathetic. The superior laryngeal nerves supply the 

 mucous membrane of the larynx, and the Crico-thyroid muscles. The inferior 

 laryngeal nerves supply the remaining muscles. The Arytenoid muscle is 

 supplied by both nerves. 



THE TRACHEA. (Fig, 428). 



The Trachea, or air-tube, is a cartilaginous and membranous cylindrical tube, 

 flattened posteriorly, which extends from the lower part of the larynx, on a 



Fig, 428. Front View of Cartilasres of Larynx ; the Trachea and Bronchi. 



Superloi* 



level with the fifth cervical vertebra, to opposite the third dorsal, where it 

 divides into the two bronchi, one for each lung. The trachea measures about 



