A myospasm is a muscle spasm - a sudden jerking or twitching caused by contraction of the muscles.
The medical term for spasm or cramp is "myospasm." Myospasm refers to the involuntary contraction of a muscle, which can cause pain and discomfort. It can occur in various muscles throughout the body and may be triggered by factors such as dehydration, overuse, or electrolyte imbalances.
Tonus is the continous baseline muscle tone in the body.
to move spasmodically or convulsively; jerk; jump