THE LARYNX. 129 



Immediately under the body of the os hyoides, between its 

 concave face and the middle thyreo-hyoid ligament, is a small 

 sac or cell formed between the laminae of this ligament, and 

 frequently extending itself downwards as far as the notch of-ehe 

 thyroid cartilage; it is flat about four or five lines in its trans- 

 verse diameter, and presents a shining surface. I have never 

 seen a fluid in it in the natural state; its secretion, however, 

 sometimes becomes excessive, and it is then elongated down- 

 wards over the front of the thyroid and of the cricoid cartilage, 

 as far as the isthmus of the thyroid gland. In this state it fre- 

 quently forms a small fistulous opening, at its lower end, through 

 the skin, and which is marked by a fold of the latter across 

 the neck. The true pathology of the disease was first pointed 

 out by the late Dr. Physick, who cured it, in some cases, by the 

 introduction of lunar caustic, and in others by extirpation. 



The Thyreo-Arytenoid Ligaments are two in number, on 

 each side of the larynx ; one above the other, at the distance 

 of three lines. The inferior is extended from the anterior an- 

 gle of the base of the arytenoid cartilage to the inferior part of 

 the entering angle of the thyroid, and, by converging towards 

 its fellow, is inserted there in contact with it. Its fibrous 

 structure is very distinct. It also bears the name of Ligamen- 

 tum Vocale, from its bordering the rima glottidis. The supe- 

 rior thyreo-arytenoid ligament arises from the middle of the 

 anterior edge of the arytenoid cartilage, and is also inserted 

 into the entering angle of the thyroid; it is more distant from 

 its fellow than the lower one, and goes almost parallel with 

 it; so that the opening between the two is both larger and 

 more like an oblong. Its fibrous structure is less distinct than 

 that of the lower. Both the upper and the lower ligaments 

 are covered by a reflection of the lining membrane of the la- 

 rynx, and are small, round fibrous threads, which are rendered 

 more or less tense by the action of the small muscles of the 

 larynx. 



The superior thyreo-arytenoid ligament is attached, in its 

 whole length, by a triangular fibro-muscular layer to the pedi- 

 cle of the epiglottis: the posterior margin of this layer is dis- 

 tinctly muscular, and must have the effect of drawing the liga- 

 ment upwards. 



