. The myology of the raven (Corvus corax sinuatus.) A guide to the study of the muscular system in birds . wards in a gentle curve, to be inserted all alongthe inner margin of the corresponding arytenoid bone,and to the apex of the mid-cricoidal segment. When this pair of muscles firmly contract together,they efficiently close the rima, and draw the apices ofthe arytenoids to the middle line, and close against theupper surface of the thyroid plate. This action of theconstrictor glottidis is opposed by the next muscle, theopener of the rimci. 29. The thyreo-arytenoideus (Figs. 10 and 18).—Thisp
. The myology of the raven (Corvus corax sinuatus.) A guide to the study of the muscular system in birds . wards in a gentle curve, to be inserted all alongthe inner margin of the corresponding arytenoid bone,and to the apex of the mid-cricoidal segment. When this pair of muscles firmly contract together,they efficiently close the rima, and draw the apices ofthe arytenoids to the middle line, and close against theupper surface of the thyroid plate. This action of theconstrictor glottidis is opposed by the next muscle, theopener of the rimci. 29. The thyreo-arytenoideus (Figs. 10 and 18).—Thispair of muscles arise, one on either side, from the entireouter margin of the thyroid plate, and the correspondingmargin of the outer cricoid bone (Fig. 10). The fibres pass inwards, directly across the opening ofthe windpipe, to be inserted all along the outer marginof the arytenoid bone of the same side, and the cor-responding border of the central cricoid piece. It isevident that the contraction of this pair will tend topull the arytenoid bones outwards, and thus open therima glottidis. Fig. 17. —The under side of the hyoid arches of a Raven, with the superior larynxand upper part of the windpipe, in situ. Designed to show the attach-ment of the muscles of the parts ; the sterm-hyoidcus and the dcido-trachcalh are pulled outwards by dissecting hooks. Life-size, by theauthor from his own dissections. Fig. 18.—Superior view of the same parts, with lower muscles removed, butshowing those attached to the upper side of the hyoid and superiorlarynx. The rima glottidis is represented as closed, with the arytenoidsin contact. The elliptical aperture, which always remains in front isclosed by the upper surface of the thyroid platebeneath it. THE MUSCLES OF THE AIR PASSAGES. 47 From the simplicity of the structmc just described,from the situation of the superior hirynx with relation tothe rictus or gape of the bill, and from the absence of lipsby which this might be par
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectmuscles, bookyear1890
