Functio laesa is a term used in medicine to refer to a loss of function[1][2] or a disturbance of function.[3]
It was identified as the fifth sign of acute inflammation by Galen, who added it to the four signs identified by Celsus (tumor, rubor, calor, and dolor).[4]
The attribution to Galen is disputed,[3] and has variously been attributed to Thomas Sydenham[5] and Rudolf Virchow.[6]