Medulla

(me-dul’-ah) [L., marrow]. I. The marrow. 2, The medulla oblong at a. 3. Anything resembling marrow in structure or in its relations to other parts — as a fatty substance or marrow occupying certain cavities. Also the central parts of certain organs, as distinguished from the cortex. M. of Nerve fiber, the white substance of Schwann. See Nerve. M. oblong at a, the upper enlarged part of the spinal cord, extending from the cord opposite the foramen magnum to the pons Varolii. M. spinal is, the spinal cord or marrow. M. of Kidney. See Kidney. 383