There are about four hundred and forty-six muscles that have been dissected and described, and the actions of which are perfectly understood. But there is probably a much larger number of muscles, and of compound actions of muscles, than the skill of man has been able to recognise.
"All flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds."—Corinthians xvi.
Fig. 57.—ILLUSTRATION OF THE RELATION OF MUSCLES, TENDONS, AND BONES.
942. What is the constitution of a muscle?
Every muscle is made up of a number of parallel fleshy fibres, or threads, which are bound together by a smooth and soft tissue, forming a sheath or case to the muscle, and enabling it to glide freely over the surfaces upon which it moves.