Chap. 21.] The Windpipe. 231 



each other, and confequently to relax the ligaments 

 which are placed between them. 



The arytenoideus obliquus arifes from the bafe of 

 one arytenoid cartilage, and eroding its fellow, is in- 

 ferted into the tip-of the other. When both act, they 

 pull the arytenoid cartilages towards each other, and 

 therefore contract the rima glottidis. 



The fingle mufcle which was mentioned is the ary* 

 tenoideus tranfverfus. It arifes from the fide of one 

 arytenoid cartilage and pafles to the other. It Hints the 

 rima glottidis by bringing the arytenoid cartilages with 

 the ligaments nearer each other. 



Befides thefe, there are a few feparate mufcular fibres, 

 which from their connections are called 



The thyreo-epiglott'.deus, which arifes from the thy- 

 roid cartilage, and is inferted into the epiglottis laterally. 

 It draws the epiglottis obliquely downwards. 



The aryteno-epiglottideus, which arifes from the 

 fide antj upper part of the arytenoid cartilage, and is 

 inferted with the former into the epiglottis j it pulls 

 down the epiglottis, and counteracts the effect of its 

 elafticity. 



The afpera arteria, or windpipe, is a tube formed of 

 annular cartilages, membranes, and mufcular fibres. It 

 begins from the annular cartilage of the larynx, de- 

 icends racher towards the right fide of the fpine into 

 the cavity of the thorax, and is divided into two great 

 branches, which being afterwards fubdivided, obtain 

 the name of bronchia, and are diftributed through the 

 fubftance of the lungs. The afpera arteria is furniflied 

 with two membranes, the outer of which is formed of, 

 cellular fubftance, and the inner is very fort and tender; 

 between thefe membranes are placed the cartilaginous 

 rings. Thefe rings are connected to each other by liga- 

 mentous fibres above and below. They do nc 



con 



