Hemorrhage

HEMORRHAGE (from Greek haima-blood and rhegnymi-I break), extravasate, extravasatio sanguinis - terms denoting the escape of blood from vessels, where the term H. is applied both to bleeding (see), i.e., the process of blood being discharged from vessels, and to hematoma (see), i.e., the accumulation of blood outside vessels as a result of bleeding. As for the fate of blood that has been extravasated into the tissues of the organism, this blood clots, and its formed elements break down. The hemoglobin from the red blood cells is leached out and undergoes a series of changes (which gives the color variation in areas of hemorrhage, e.g., in 'bruises' of the skin), eventually turning into pigments-hemosiderin (see) and hematoidin (see Hemoglobin). Subsequently, such a mass of breaking-down blood is resorbed; large hematomas are replaced by connective tissue and organized. As a result, small hemorrhages into tissues may be resorbed without a trace, whereas at the site of a larger hematoma a scar forms, pigmented brown by the blood pigment, or (e.g., in the brain) a cyst with similarly pigmented walls and brownish semi-liquid contents. Haemorrhagia cerebri, see Apoplexy. Lit.: Aschoff L., Pathologische Anatomie, Band I, Jena, 1928; Binet L., Questions physiologiques d'actualite, Paris, 1927; Delaunay H., Hemorragies (Traite de physiologie normale et pathologique, publie sous la direction de G. Roger et L. Binet, t. VII, P., 1927).