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fibrous membrane which connects the cartilaginous rings of 

 the trachea. 



The intrinsic ligaments connecting the thyroid and cricoid 

 cartilages are the cricothyroid membrane, two capsular liga- 

 ments. The cricothyroid ligament is of yellow elastic tissue, 

 triangular, and consists of a central thicker portion connecting 

 the adjacent borders of the two cartilages, and two lateral 

 portions running from the upper border of the cricoid to be 

 continuous with the inferior thyroarytenoid ligaments (true 

 weal cords). They extend from the vocal processes of the 

 ary tenoid cartilages to the receding angle of the thyroid cartilage 

 near its centre. The lateral portions of the membrane are 

 lined internally by mucous membrane, and are separated from 

 the thyroid cartilage by the cricoarytenoideus lateralis and 

 thyroarytenoideus muscles. In the subcutaneous interval 

 there is a sort of plexus from the junction of the two crico- 

 thyroid arteries. The lower cornua of the thyroid are connected 

 with the sides of the cricoid by two ligamentous capsules 

 each lined by a synovial membrane. 



The cricoid and arytenoid cartilages are connected by loose 

 capsular ligaments lined by synovial membranes, and by a 

 posterior cricoarytenoid ligament running from the cricoid 

 to the inner and back part of the base of the arytenoid. The 

 movements between the inferior cornu of the thyroid and the 

 cricoid cartilage on either side is a diarthrodial one, and per- 

 mits of rotary and gliding movements. The movements 

 between the arytenoid cartilages and the cricoid is also a 

 diarthrodial one gliding and rotary. 



The interior of the larynx (cavum laryngis) is divided into 

 an upper and a lower part by the rima glottidis. The upper 

 opens into the pharynx by the upper aperture of the larynx, 

 between which and the rima glottidis are the ventricles and 

 their saccules and the false vocal cords. The lower aperture 

 is continuous with the trachea. 



The superior aperture is cordiform in shape, widest in front 

 and narrow behind. In front it is bounded by the epiglottis, 

 behind by the arytenoid cartilages (together with the fold of 

 mucous membrane between them) and cornicula, and laterally 

 by the arytenoepiglottic folds. 



The rima glottidis is the space between the true vocal cords 

 and the bases of the arytenoid cartilages. It is somewhat 



