Adjective
(anatomy, medicine) Outside of a medulla; thus:
(anatomy, medicine) Outside of the bone marrow, as with extramedullary hematopoiesis.
(anatomy, medicine) Outside of the medulla oblongata, as with extramedullary influences on control of ventilation.
(anatomy, medicine) Outside of the renal medulla, as with extramedullary electrolytes or renal tissue.
(anatomy, medicine) Outside of the spinal cord, as with intrameningeal but extramedullary tissues of the central nervous system.
Source: en.wiktionary.orgIn adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum. citation Extramedullary In some cases, the liver, thymus, and spleen may resume their haematopoietic function, if necessary. Source: Internet