A small bluish-grey area within the brain, located on either side of the rostral end of the floor of the fourth ventricle, made up of pigmented nerve cell bodies having noradrenergic axons distributed to many parts of the central nervous system, and considered to be part of the reticular formation.
locus caeruleus/ˌləʊkəs sɪˈruːlɪəs/ /ˌlɒkəs sɪˈruːlɪəs/
Mid 19th century; earliest use found in George Viner Ellis (1812–1900). From scientific Latin locus caeruleus (J. Wenzel & C. WenzelDe penitiori structura cerebri 341; also caeruleus locus (xvii. 168, in the same source)) from classical Latin locus + caeruleus.