904 



THE ORGAXS OF VOICE 



The superior border liounds the quadrate plate above, and then passes obUquely 

 downwards and forwards. An oval, convex, obliqueh' placed articular surface, upon 

 which moves the arytenoid cartilage, separates these two portions of the upper 

 border on each side. 



The o])lique half gives attachment to the crico-thyroid meml)rane, and, laterally 

 and external to this, to the lateral crico-arytenoid muscle. 



The inferior border — horizontal, and often deejily notched at the sides — is 

 attached to the tirst ring of the trachea by fibrous membrane. 



The arytenoid cartilages are irregular, three-sided pyramids, which articulate 



Fio. 525. — Front View of the Cricoid and Arytenoid Cartilages. (Modified 



from Bourgery and Jacob.) 



Thyro-arytenoideus muscle 



Attachment of crieo-thyroid muscle 



ANTERIOR SURFACE OF ARYTENOID CARTILAGE 



Cut edge of capsular ligament 

 Lateral crico-arytenoid muscle 



MUSCULAR EXTERNAL ANGLE OF ARYTENOiO 

 CARTIUGE 



Lateral crico-arytenoid muscle 



CRICOID CARTILAGE 



l3y their leases with the oblique facets on the superior border of the cricoid cartilage, 

 and support upon their apices the cornicula laryngis. 



The space between them in certain animals has been likened to the mouth of a 

 pitcher, and hence their name. Each cartilage presents three surfaces, divided by 

 three borders, with a base, apex, and angles. 



The surfaces. — The posterior is concave, smooth, and gives attachment to the 

 arytenoid muscle. 



The anterior is irregular and convex. It gives attachment by a small tuljercle 

 to the false vocal cord, and also to the thvro-arvtenoid muscle. 



Fig. 526. — Back View of the Cricoid and Arytenoid Cartilages. (Modified 

 from Bourgery and Jacob. ) 



CORNICULUM LARYN&IS 



POSTERIOR SURFACE OF ARYTENOID 



MUSCULAR EXTERNAL ANGLE 

 Crico-arytenoid joint 



MEDIAN RIDGE 



POSTERIOR SURFACE OF CRICOID 

 CARTILAGE 



Longitudinal fibres of cesophagus 



Arytenoideus muscle 



Crico-arytenoideus posticus muscle 



Crico-arytenoideus posticus muscle 



. ARTICULAR SURFACE FOR INFERIOR CORNU 

 OF THYROID CARTILAGE 



The internal is almost flat, smooth, and narrow, and covered by mucous 

 membrane. 



The base is obliquely hollowed, and presents internally the facet for articulation 

 witli the cricoid cartilage. 



The angles. — Tht- anterior is ]>rolonged for tlie attachment of the true vocal 

 cord. It is known as tlic vocal process, and with the aid of the laryngoscope is 

 easily seen during life. 



The external or muscular is thick and l)lunt. and gives attachment in front to 

 the lateral crico-arytenoid, and l)ehind to the i)osterior crico-arytenoid mu.scle. 



