APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Antagonistic Muscle is a muscle that opposes the action of another. For example, when the triceps oppose the contraction of the flexing biceps by relaxing, the triceps would be regarded as the antagonistic muscle to the biceps whereas the biceps, the agonist muscle.

Detailed explanation-2: -In an antagonistic muscle pair as one muscle contracts the other muscle relaxes or lengthens. The muscle that is contracting is called the agonist and the muscle that is relaxing or lengthening is called the antagonist.

Detailed explanation-3: -When discussing movement at a joint, the muscle performing the action on one side of the joint is called the agonist, and the muscle on the other side of the joint with the potential to oppose the action is called the antagonist. Basically agonists and antagonists are just opposites.