170 VISCERAL ANATOMY. 



and the margin of the epiglottis. Action, to compress the sacculus 

 laryngis. Nerve, recurrent laryngeal. 

 Name the Arteries and Veins of the Larynx. The 

 Arteries, are the Laryngeal Branches of the superior and inferior thyroid ; 

 and the Crico-thyroid Branches of the superior thyroid, which anastomose 

 on the crico thyroid membrane with their fellows of the opposite side. 

 Veins, empty into the superior, middle and inferior thyroid veins. 



Describe the Laryngeal Nerves. They are the Superior and Recurrent 

 Laryngeal Branches of the pneumogastric, joined by filaments from the spinal 

 accessory and the sympathetic. The 



Superior Laryngeal, is the nerve of sensation. It enters the larynx by a 

 hole in the thyro-hyoid membrane, and supplies the mucous membrane, 

 and the crico-thyroid and arytenoideus muscles. It has the following 

 branches, namely 



External Laryngeal. Internal Laryngeal. 



Recurrent Laryngeal, is the motor nerve. It winds from before back- 

 wards, around the subclavian artery on the right side, around the arch of 

 the aorta on the left side, and is distributed to all the laryngeal muscles 

 except the crico-thyroid, giving off, in its course, cardiac, cesophageal, 

 tracheal and pharnygeal filaments, and finally anastomosing with the 

 superior laryngeal nerve. 



THE TRACHEA AND BRONCHI. 



What is the Trachea ? A membrano-cartilaginous, cylindrical tube, 

 about 4*4. inches long, and ^ to I inch in diameter, beginning at the lower 

 border of the larynx, 2 opposite the 5th cervical vertebra, and ending opposite 

 the 3d dorsal, by its bifurcation into the two bronchi. It is composed of a 

 fibro elastic membrane containing 1 6 to 20 imperfect cartilaginous rings, con- 

 nected by muscular fibres. It is lined with mucous membrane covered with 

 ciliated columnar epithelium, and furnished with glands. Its anterior surface 

 is convex, its posterior surface flat. 



State its Chief Relations in the Neck and Thorax. 

 Anteriorly, -it is covered from above downwards by the 



Isthmus of the Thyroid Gland. Thymus Gland. 



Inferior Thyroid Veins. Arch of the Aorta. 



Sterno-hyoid Muscle. Innominate Artery. 



Sterno-thyroid Muscle. Left Carotid Artery. 



Manubrium of the Sternum. Deep Cardiac Plexus. 



Posteriorly, it is in relation with the 



(Esophagus. Right Recurrent Laryngeal Nerve. 



