Functio laesa

Functio laesa is a term used in medicine to refer to a loss of function or a disturbance of function.

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).

The attribution to Galen is not undisputed. Origination of the phrase has also been ascribed to Thomas Sydenham and Rudolf Virchow.