medulla (med-ul'lah). i

See marrow. 2. The pith of a plant, aeriferous m. The central or medullary portion of a hair, containing air within or between the cells. See air lacunule, under lacunule. central m. The m. proper or pith, cortical m. Cortical parenchyma. external m. See cortical m. fetal m. See fetal marrow, m. bovilla, m. bovina, m. bo vis. See beef marrow, under marrow, m. ciliaris. See corpus dentatum. m. oblong at a. That portion of the encephalon which rests in the basilar groove, being limited above by the lower borders of the pons and continuous at the lower edge of the foramen magnum with the spinal cord. It is covered in posteriorly by the cerebellar hemispheres. As originally used, the term included also the pons Varolii and crura cerebri, m. of a hair. The hair pith. m. of a nerve fiber. The white substance of Schwann, m. of bone, m. o ium. See marrow, m. spinae, m. spinal is, m. vertebral is. See spinal cord, under cord. [Lat.]