Human physiology : designed for colleges and the higher classes in schools and for general reading . In this Figure, C is the tendon of the great toe in its position asbound down by ligaments. Now if the muscle were in theposition represented, by A, it is plain that it would act at agreater mechanical advantage than in the position C; but thetoe would not be moved as quickly; and besides, if the tendonsprojected in this way, the foot would be a very cumbrous pieceof machinery, compared with what it is now, with the tendonsbound down around the slender ankle. So that both beautyand use are secu
Human physiology : designed for colleges and the higher classes in schools and for general reading . In this Figure, C is the tendon of the great toe in its position asbound down by ligaments. Now if the muscle were in theposition represented, by A, it is plain that it would act at agreater mechanical advantage than in the position C; but thetoe would not be moved as quickly; and besides, if the tendonsprojected in this way, the foot would be a very cumbrous pieceof machinery, compared with what it is now, with the tendonsbound down around the slender ankle. So that both beautyand use are secured by the arrangement. 306. There is a beautiful application of the pulley in thecase of the muscle that draws down the lower jaw, calledthe digastric muscle. It is represented in Fig. 120, in whicha is one end of the muscle attached behind the ear, and b is theother end attached to the inside of the lower part of the chin. THE MUSCLES. 207 Manner in which the lower juw is drawn DIGASTRIC MUSCLE. It is muscular at the two ends, and tendinous in its middlepart. This middle part runs through a loop or ring in a smallmuscle as represented in the Figure. This little muscle isfastened above to a small process of bone under the ear, andbelow to the hyoid, or U-shaped bone, c, which is situated justabove the larynx. Now when the jaw is to be drawn down,the two fleshy ends of the digastric muscle contract, and themiddle tendinous part works in the ring provided in the littlemuscle. This muscle is so slender, that its loop is of itself alonehardly strong enough, as we should suppose, for the tendon ofso large a muscle as the digastric to work in. And we accord-ingly find that there is an additional security in a strong liga-ment, which fastens the tendon of the digastric muscle to thehyoid bone. This ligament (which I have not represented inthe figure, because it would confuse your view of the pulley-action of the parts) is sufficiently long to allow of all thefreedom
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Keywords: ., bookauthorhookerwo, bookcentury1800, bookdecade1850, bookyear1854
