ABSTRACT
The same two classes of differences become obvious when the muscles of the hand are compared with those of the foot.
Three principal sets of muscles, called “flexors,” bend the fingers and thumb, as in clenching the fist, and three sets,—the extensors-extend them, as in straightening the fingers. These muscles are all “long muscles;” that is to say, the fleshy part of each, lying in and being fixed to the bones of the arm, is, at the other end, continued into tendons, or rounded cords, which pass into the hand, and are ultimately fixed to the bones which are to be moved. Thus, when the fingers are bent, the fleshy parts of the flexors of the fingers, placed in the arm, contract, in virtue of their peculiar endowment as muscles; and pulling the tendinous cords, connected with their ends, cause them to pull down the bones of the fingers towards the palm.
