Diseases of the nose and throat; a text-book for students and practitioners . in certain subjects theycan be felt under the skin duringtheir contraction. Their action isto tilt the anterior portion of thethyroid downward, thus bringingthe thyroid and cricoid cartilagescloser together anteriorly ; the tilt-ing motion serving to increase thedistance between the vocal proc-esses of the arytenoid cartilagesand the anterior receding angle ofthe thyroid cartilage, thus stretch-ing the vocal bands antero-poste-riorly. According to some authori-ties, notably Majendie (1813) andHooper (1882), the crico
Diseases of the nose and throat; a text-book for students and practitioners . in certain subjects theycan be felt under the skin duringtheir contraction. Their action isto tilt the anterior portion of thethyroid downward, thus bringingthe thyroid and cricoid cartilagescloser together anteriorly ; the tilt-ing motion serving to increase thedistance between the vocal proc-esses of the arytenoid cartilagesand the anterior receding angle ofthe thyroid cartilage, thus stretch-ing the vocal bands antero-poste-riorly. According to some authori-ties, notably Majendie (1813) andHooper (1882), the cricoid islooked upon as the movable carti-lage ; the thyroid, the fixed. If this be true, the cricoid is drawnup to the thyroid. In either case, the result is the same asregards the action of the muscles, which are tensors of thevocal bands. The posterior crico-arytenoids (abductors) are two trian-gular muscles which arise from the posterior surface of thecricoid cartilage, as stated; the fibres converge as they passupward and outward, each muscle going to the muscular process. Fig. 88.—Posterior Crico-Abytenoid Muscles. (Fioixi a photograph ) ANATOMY AND PHYSIOLOGY OF THE LARYNX. 329 of tlie corresponding arytenoid cartilage. Contraction of thesemuscles rotates the arytenoids m such a way that the muscularprocesses are approximated and the vocal processes and bandsseparated. In rare cases there is an extra muscle, very smalland often unilateral—the IceratOCricoid. It arises near the originof the posterior crico-arytenoid, and passes upward and out-ward to the posterior margin of the inferior thyroid horn. Itsfunction is doubtful, but may aid in fixing the inferior cornu,opposing, to a slight degree, the fibres of the crico-thyroidwhich pass to the anterior margin of the horn. The lateral crico-arytenoid (adductor) muscles pass (Fig. 89)from the upper margin and outer ftice of the sides of the cricoid Arr-cpifrlottic fold Cartilage of Sautorini Pyriform sinus Arvtenoidens muscl
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherph, booksubjectnose
