PART VI 



THE ORGANS OF RESPIRATION 

 THE LARYNX 



THE larynx is the organ of the voice, and is placed at the 

 upper and forepart of the neck, between the trachea and base 

 of the tongue. 



Relations. It has on each side of it the great vessels, and 

 behind it the pharynx. In front are the pretracheal portion 

 of the cervical fascia and the upper end of the thyroid gland, 

 and on each side the sternohyoid and thyroid and the thyro- 

 hyoid muscles. It consists of various cartilages held together 

 by ligaments, and is lined internally by mucous membrane. 



The cartilages are nine : Three pairs, the ary tenoid, cornicula 

 laryngis, and cuneiform; and three single, the thyroid, cricoid, 

 and epiglottis. 



The thyroid cartilage is the largest, and consists of two lateral 

 parts or alre uniting in front to form the projection of the 

 pomum Adami. This is subcutaneous, more distinct above 

 and in the male. Each ala is quadrilateral, and presents 

 externally a tubercle from which a ridge descends obliquely 

 forward. This ridge gives Attachment to the sternothyroid 

 and thyrohyoid, and the surface behind it to the inferior con- 

 strictor muscle. Internally it is smooth, and in the angle the 

 epiglottis, true and false vocal cords, and the thyroarytenoid 

 and thyroepiglottidean muscles are attached. The upper 

 border is concavoconvex, and in front is notched over the 



