A muscle that is the primary actor in a given movement, that is, the muscle that produces the movement in muscle contraction.
main muscle used to produce a movement
muscles that oppose the movement of the agonist
muscles that assist the action of the agonist
a muscle that stabilizes a joint in one position during the movement of another
also called sphincters; open and close to guard entrances of body; ex: orbicularis oris muscle of the mouth
the muscle fibers are based over a broad area, but all fibers come together at a common attachment site.
the fascicles are parallel to the long axis of the muscle. Most of the muscles in the body are parallel muscles.
Muscle that is thick in the middle and tapered at each end
Muscle that is feather-shaped