medulla

(me-dul'ah) [L. marrow.] Any soft marrow-like structure, especially in the center of a part. Specifically, (i) bone-marrow, (2) the spinal cord, (3) the medulla oblong at a, m. oblong a'ta [BNA], the prolongation of the spinal cord into the brain, extending from the lower end of the decu ation of the pjrramids to the pons Varolii; it is about an inch long, cylindrical in shape, somewhat enlarged at its upper extremity, its anterior surface resembling in configuration the spinal cord, and posteriorly forming part of the floor of the fourth ventricle. m. os's ium [BNA], the bone-marrow, m. spina'lis [BNA], spinal marrow, spinal cord; the elongated cylindrical portion of the cerebrospinal axis, or central nervous system, which is contained in the canal of the spinal or vertebral column.