Muscles that oppose unwanted joint motions created by the prime mover and/or synergists, and/or muscles that prevent unwanted ancillary motion. Example: The teres minor and infraspinatus neutralize the internal rotation force created by the pectoralis major during horizontal adduction of the shoulder.

Related Terms

  • Synergist muscles
  • Prime mover muscles
  • Muscle contraction
  • Muscle anatomy


  • Antagonist muscles
  • Antagonistic muscle groups
  • Opposing muscles
  • Neutralizer