The exterior of the horse . spine, etc., take place through the mechanism of an inter-fixed lever in whichthe arm of power is, according to the case, the olecranon, the calcaneum, the tro-chanter, the ischial tuberosity, the spinous or transverse apophyses of the the economy the lever of the first class appears to be more particularly reservedfor extension. It is also the lever of speed, for the arm of power is never equal tothat of resistance : the latter is always much hjnger. In man, whose standing position is vertical, in whom falling forward iseasy, on account of the particul
The exterior of the horse . spine, etc., take place through the mechanism of an inter-fixed lever in whichthe arm of power is, according to the case, the olecranon, the calcaneum, the tro-chanter, the ischial tuberosity, the spinous or transverse apophyses of the the economy the lever of the first class appears to be more particularly reservedfor extension. It is also the lever of speed, for the arm of power is never equal tothat of resistance : the latter is always much hjnger. In man, whose standing position is vertical, in whom falling forward iseasy, on account of the particular situation of the organs, the lever of the firstkind is, with good reason, to be considered as the lever of station. We shall seethat in animals it is that of the second class in whicITtKis usagé can be prefer-ably recognized. In the lever of the second class the resistance occupies the intermediate posi-tion (Fig. 8). The name inter-resisting is applied to it. In this case, whatever THE LEVElt AXD MUSCULAR MECJIAXISM. 1. may be the respective positions of the three points, the lever-arm of power exceedsthat of resistance, since PA always remains hyitotiietically lonirer tlian AM. Thislever is, then, very truly thatof force, but has more disad-vantage concerning the pro-duction of speed, for, thelatter Ixinii i)roportional tothe lever-arm, the path of theresistance will never be asIcjng as that of the power. Several examples are seenin animals. ^It is well knownthat while standing the weightof the body tends to close allthe articular angles of thememitcrs upon each oûuny Fk;. s. There are also observed, on the convex side or the sumniit of the latter, muscles which are opposed to thisclosing, by acting as levers of the second class. It is thus that the supra-spina-tus, the coraco-radialis, the sul)-spinatus, the subscapular, sustain the scapulo-humeral angle. The insertions of these difierent muscles are all situated a littlebeyond the articulation, which represents the poi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjecthorses, bookyear1892
