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SPLAXCHNOLOGY^ 



Cavity of the larynx— opened posteriorly. 

 a a, Lateral ventricles of the larynx ; b, Middle 

 ventricle ; c c. True vocal cords. 



numerous on the posterior as- 

 pect of the epiglottis, iu front 

 of the arytenoids, and in the 

 laryngeal ventricles. 



The larynx is supplied with 

 blood from the laryngeal arteries. 

 The nerves are from the superior 

 and inferior larj^ngeal branches 

 of the vagus ; twigs also come 

 from the sympathetic. 



The larynx gives passage to 

 the air of resjiiration, prevents 

 the intrusion of food into the 

 air-tubes by closure of its lid, 

 the epiglottis ; and it contains 

 the organ of voice, the latter 

 being produced by vibration of 

 the true vocal cords. 



TRACHEA. 



The trachea, or windpipe, is a nearly cylindrical and flexible 

 tube, consisting of a series of incomplete cai'tilaginous rings. It 

 succeeds the larynx, runs down the neck, enters the thorax, and 

 terminates at the base of the heart, where it divides into the 

 right and left bronchi. Like the neck, it varies in length, and 

 consists of forty or fifty rings, the ends of which overlap pos- 

 teriorly, forming a perfect expansile tube. It presents a number 

 of transverse furrows, which correspond to the interspaces between 

 the rings. The latter vary in depth, averaging half-an-inch, and 

 they are completed and united by strong elastic ligaments. The 

 first is attached to the cricoid cartilage by a baud called the 

 crico-trachealis ligament. The ligaments contain involuntary 

 muscular fasciculi, and they are attached by their extremities to 

 the inner and posterior surface of the rings, and to their ends, so 

 completing each ring. 



The entire trachea is lined by mucous membrane, which is 

 continuous with, but not so sensitive as, that of the larynx ; 

 it is clothed with ciliated epithelium, and studded with glands. 

 The trachea is related with the oesophagus and carotid arteries, 

 the latter running along its sides. The arteries supplying the 



