APRN Pathophysiology: Muscles, Joints, and Connective Tissues

Course overview

Most skeletal muscles work in groups. The prime mover is the muscle that contracts to produce the movement. Synergists are muscles that work with prime movers to assist in performing the movement. Antagonists are muscles that work opposite prime movers by relaxing during their contraction or by producing an opposite effect. For example, the arm is flexed by contracting the biceps brachia, which acts as the prime mover; at the same time, the triceps brachii on the opposite side of the humorous relaxes, acting as the antagonist (Figure 1). When the arm is extended, the roles of the biceps and triceps are reversed. An isotonic contraction occurs when a muscle shortens during contraction. An isometric contraction occurs when a muscle becomes tense while remaining the same length