tonus
- n the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli
- Three constant reactions occur within one to four seconds before the respiratory gaspan increase in muscle tonus, a stiffening of the arms, and a slight opisthotonos arching .
- The massaging action of the abdominal muscles needed to keep the internal organs in a state of tonus is provided by the leg thrash, which is controlled by muscles originating on .