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The biceps muscle and arm bones, to illustrate how, under ordinary circumstances, the elbow-joint is flexed when the muscle contracts.

The Biceps Muscle and Arm Bones

The biceps muscle and arm bones, to illustrate how, under ordinary circumstances, the elbow-joint is…

Wave of contraction passing over a muscular fiber of dytiscus, very highly magnified. When a muscle contracts, the dark bands swell up and shorten (the light bands are also constricted), and the whole fiber broadens and shortens. Labels: R, R, portions of the fiber at rest; C, contracted part; I, I, intermediate condition.

Muscular Fiber Contracting

Wave of contraction passing over a muscular fiber of dytiscus, very highly magnified. When a muscle…