476 THE LARYNX. 



or lateral half arches can be seen on each side, with the tonsil 

 between them. 



Of the Larynx. f 



The larynx is situated immediately below the os hyoides, 

 and is continuous at its inferior part with the trachea, to which 

 it is attached, like a capital upon a column. It serves a double 

 purpose ; that of a tube for the introduction of air into the 

 lungs ; and that of a very complicated apparatus for the pro- 

 duction of the voice. 



It is composed of cartilages which form its frame-work, liga- 

 ments and synovial capsules which unite the cartilages together, 

 muscles to put them into motion, and an exquisitely sensitive 

 mucous membrane, that lines the whole of its interior. It is 

 larger and much more prominent in males than females, and 

 undergoes a rapid and remarkable degree of development, 

 both in regard to size and energy of function at the period of 

 puberty. 



In this structure are five cartilages, upon which its form and 

 strength depends, namely, the Cricoid, the Thyroid, the two 

 Arytenoid, and the Epiglottis. These cartilages are articulated 

 to each other, and are supplied with muscles by which certain 

 limited motions are effected. 



The basis of the structure is a cartilaginous ring, called the 

 cricoid cartilage, and which may be considered as the com- 

 mencement of the windpipe. 



It may be described as an irregular section of a tube : its 

 lower edge connected with the windpipe, being nearly hori- 

 zontal when the body is erect ; and the upper edge very oblique, 

 sloping from before, backwards and upwards ; in consequence 

 of this, it has but little depth, before, but is eight or nine lines 

 deep behind. 



In front, and upon each side of the middle line there is a 

 depression, in which arises the two crico-thyroid muscles. Upon 

 each side, and near its upper and outer surface, there is a 

 smooth convex facet, upon which is articulated, the corres- 



