The consecutive events that occur in a living body following injury are commonly referred to as inflammation (inflammare: to set on fire). In the first century a.d. Observations of clinical patients had allowed cornelius celsus to formulate his famous “cardinal signs” of inflammation: calor, rubor, tumor and dolor. These still holds true today. The four characteristics of inflammation are redness and swelling with heat and pain. From these early studies it was obvious that blood vessels played an important role in the development of an inflammatory process, which coincided with plasma leakage and accumulation of leucocytes in extravascular tissue.
Stad, R. K., & Buurman, W. A. (1994). Current views on structure and function of endothelial adhesion molecules. Cell Adhesion and Communication, 2(3), 261-8. https://doi.org/10.3109/15419069409004446