. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. THORAX. 1053 Fig. Angle of tension. Tensi At 90° 2-5 „ 75° 2'5 „ 46° 2'5 „ 15° 2'5 7° 2-5 the bars increases with the increasing obliquity of these tensions. By experiment we found that equal tensions at the following angles, pro- duced the following difference of power in rotating the bars : — TABLE H. — Power gained by a given Tension, as an intercostal Muscle, in relation to its Obliquity. Resistance. 0 1-50 2-25 4-25 5-50 The power descreases as the tension ap- proaches the perpendicular L K', and increases as
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. THORAX. 1053 Fig. Angle of tension. Tensi At 90° 2-5 „ 75° 2'5 „ 46° 2'5 „ 15° 2'5 7° 2-5 the bars increases with the increasing obliquity of these tensions. By experiment we found that equal tensions at the following angles, pro- duced the following difference of power in rotating the bars : — TABLE H. — Power gained by a given Tension, as an intercostal Muscle, in relation to its Obliquity. Resistance. 0 1-50 2-25 4-25 5-50 The power descreases as the tension ap- proaches the perpendicular L K', and increases as it approaches L A ; this is the maximum point: if the tension be attached to the body E E, either above A or below it, the system is changed into that of a single lever. From this we gather, that the power of an intercostal muscle, as an elevator and depressor of the ribs, increases with its obliquity; and that this movement entirely depends upon its obliquity. This is the only instance in the body where the power of a muscle increases with its obliquity. Of the obliquity of the ribs or bars with re- ference to the spine. — A given tension, say at the angle of 45°, will, when the lever is at 90° to the spine act more powerfully than when the lever is at an angle similar to that of the ribs. We found by experiment, that the bars in the following positions required an increased power to sustain them. The tension being uniform, and the resistance to be overcome acting from the same point. This gain of power is dependent upon the obliquity of the bars and change in the direc- tion of the tension, for in each of these posi- tions the tension was maintained the same. But if the tension be not kept uniform, still the resistance is increased as the bars rise ; thus, if the bars are at the angle of 50° (fig. 699. »i") somewhat similar to the position of the ribs, and these under a certain tension allowed to resist a power of 4, when they are moved upwards to 9
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