n.
the enlarged extension upwards within the skull of the spinal cord, consisting of the medulla oblongata, the pons, and the midbrain. The pons and medulla are together known as the bulb, or bulbar area. Attached to the midbrain are the two cerebral hemispheres. See brain.
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brain·stem (brānґstem) the stalklike portion of the brain connecting the cerebral hemispheres with the spinal cord and comprising the mesencephalon, pons, and medulla oblongata; the diencephalon is considered part of the brainstem by some. Called also truncus encephalicus [TA]. Also written brain stem.Medical dictionary. 2011.