Mus"cle (?), n. [F., fr. L. musculus a muscle, a little mouse, dim. of mus a mouse. See Mouse, and cf. sense 3 (below).]

1. Anat. (a)

An organ which, by its contraction, produces motion

. See Illust. of Muscles of the Human Body, in Appendix. (b)

The contractile tissue of which muscles are largely made up.

⇒ Muscles are of two kinds, striated and nonstriated. The striated muscles, which, in most of the higher animals, constitute the principal part of the flesh, exclusive of the fat, are mostly under the control of the will, or voluntary, and are made up of great numbers of elongated fibres bound together into bundles and inclosed in a sheath of connective tissue, the perimysium. Each fiber is inclosed in a delicate membrane (the sarcolemma), is made up of alternate segments of lighter and darker material which give it a transversely striated appearance, and contains, scattered through its substance, protoplasmic nuclei, the so-called muscle corpuscles.

The nonstriated muscles are involuntary. They constitute a large part of the walls of the alimentary canal, blood vessels, uterus, and bladder, and are found also in the iris, skin, etc. They are made up of greatly elongated cells, usually grouped in bundles or sheets.


Muscular strength or development; as, to show one's muscle by lifting a heavy weight.


3. [AS. muscle, L. musculus a muscle, mussel. See above.] Zool.

See Mussel.

Muscle curve Physiol., contraction curve of a muscle; a myogram; the curve inscribed, upon a prepared surface, by means of a myograph when acted upon by a contracting muscle. The character of the curve represents the extent of the contraction.


© Webster 1913.