In medicine, jactitation (sometimes jactation) is a restless tossing in bed, seen in severe
fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
s and certain
mental disorder
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
s;
or more generally a tossing to and fro or jerking and twitching of the body.
It derives ultimately from the Latin ''jactitare'', to toss about.
References
Symptoms and signs: musculoskeletal system
{{med-sign-stub