400 SPLANCHNOLOGY, OR ANATOMY OF THE VISCERA 



pomum Adami, giving attachment throughout to the thyro- 

 hyoid membrane. The lower border is joined to the cricoid 

 cartilage by the middle portion of the crico thyroid membrane; 

 and on either side, affords attachment to the cricothyroid 

 muscle. The posterior borders end in the upper and lower 

 cornua; to the upper are attached the lateral thyrohyoid liga- 

 ments, and the lower, which are shorter and thicker, present 

 internally a facet for articulation with the side of the cricoid car- 

 tilage. The stylopharyngeus and palatopharyngeus is attached 

 also to the posterior border. 



The cricoid cartilage resembles a signet ring, is narrow in 

 front, and gives attachment to the cricothyroid muscle, and 

 behind it to some of the fibers of the inferior constrictor. It 

 is broad behind, with a vertical ridge for the attachment of 

 the longitudinal fibers of the esophagus, separating two hollows 

 for the cricoarytenoideus posticus, and presents at about the 

 middle of the lateral surface a prominence on each side which 

 articulates with the corresponding inferior cornu of the thyroid 

 cartilage. The lower border is joined to the upper ring of the 

 trachea; the upper border gives attachment in front and laterally 

 to the cricothyroid membrane and the lateral cricoarytenoideus 

 muscle. Behind, at each end of its upper border, is an oval 

 surface for the corresponding arytenoid cartilage, with a notch 

 between. The inner surface is smooth and lined with mucous 

 membrane. 



The arytenoid cartilages are pyramidal in form, presenting 

 three surfaces, an apex and base, and rest by their bases on 

 the highest part of the upper border of the cricoid cartilage 

 behind, their curved apices approximating. To the posterior 

 surface is attached the transverse portion of the arytenoid 

 muscle. The anterolateral surface is somewhat convex and 

 rough. From the colliculus, near the apex, starts a ridge 

 (crista arcuata) which passes backward then forward and 

 downward into a sharp pointed process, the vocal process. 

 The latter separates a deep depression above, the fovea tri- 

 angularis, from a broader and shallower depression below, 

 the fovea oblongata. To a small tubercle just above the base, 

 on the anterior border, is attached the origin of ligament of 

 the false vocal cord, the superior thyroarytenoid ligament. 

 To the outer part of the ridge, as well as the surface above 

 and below, is attached the thyroarytenoid muscle. 



