GLOTTIS AND LARYNGEAL POUCH. 157 



the outer surface of the arytoenoid cartilage. This ligament consists chiefly 

 of white fibrous tissue, which is continuous with that in the arytueno-epi- 

 glottidean fold of mucous membrane. 



The inferior ligament (chorda vocalis, fig. 42, B ) is attached in front to 

 the angle of the thyroid cartilage, about half-way down below the notch ; 

 the ligament is directed backwards, and is inserted into the anterior promi- 

 nence at the base of the arytitnoid cartilage. It is about seven lines long 

 in man, and two less in the woman. Internally this band is covered by 

 thin mucous membrane, and projects towards its fellow into the cavity of 

 the larynx, the interval between it and the opposite one being the glottis. 

 Externally it is connected with the thyro-arytaenoid muscle And infe- 

 riorly it is continuous with the crico-thyroid ligament, K. The edge that 

 bounds the ventricle is straight and well defined, and vibrates to produce 

 sounds. The ligament is composed of fine elastic tissue. 



The mucous membrane of the larynx is continued from that investing 

 the pharynx, and is prolonged to the lungs through the trachea. When 

 entering the larynx it is stretched between the epiglottis and the tip of 

 the arytenoid cartilage, forming the arytajno-epiglottid fold on each side of 

 the laryngeal orifice: at this spot it is very loose, and the submucous tissue 

 abundant. In the larynx the membrane lines closely the cavity, sinks 

 into the ventricle, and is prolonged into the laryngeal pouch. On the 

 thyro-arytenoid ligaments it is very thin and adherent, allowing these to 

 be visible through it. 



In the small part of the larynx above the vocal cords, the epithelium is 

 of the laminar kind, and free from cilia. But a columnar ciliated epithe- 

 lium covers the surface below the level of the superior cords, though it 

 becomes flattened without cilia on the cords : on the epiglottis it is ciliated 

 in the lower half. 



Numerous branched glands are connected with the mucous membrane 

 of the larynx, and the orifices will be seen on the surface, especially at 

 the posterior aspect of the epiglottis. In the edge of the arytaeno-epiglot- 

 tidean fold there is a little swelling occasioned by a mass of subjacent 

 glands (arytoenoid) ; and along the upper vocal cord lies another set. 

 None exist over the vocal cords, but close to those bands is the collection 

 of the sacculus laryngis, which lubricates the ventricle and the lower vocal 

 cord. 



Dissection of nerves and vessels. The termination of the laryngeal 

 nerves may be dissected on the untouched side of the larynx. For this 

 purpose the other half of the thyroid is to be disarticulated from the cri- 

 coid cartilage, care being taken of the recurrent nerve, which lies near 

 the joint between the two. The trachea and larynx should be fastened 

 down next with pins; and after the thyroid has been drawn away from 

 the cricoid cartilage, the inferior laryngeal nerve can be traced over the 

 side of the latter cartilage to the muscles of the larynx, and mucous mem- 

 brane of the pharynx. 



Afterwards the superior laryngeal is to be found as it pierces the thyro- 

 hyoid membrane, and branches of it are to be followed to the mucous 

 membrane of the larynx and pharynx. Two communications are to be 

 looked for between the laryngeal nerves ; one is beneath the thyroid car- 

 tilage, the other in the mucous membrane of the pharynx. 



An artery accompanies each nerve, and its offsets are to be dissected at 

 the same time as the nerve. 



