• Axial portion of the brain exclusive of the cerebellum and the forebrain; includes midbrain, medulla, and pons.
  CRISP Thesaurus
  National Institutes of Health, 2006
• The part of the brain that connects the brain with the spinal cord and controls movement, sensation, and reflexes.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• The part of the brain that is connected to the spinal cord.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• Three sections, the midbrain, pons and medulla oblongata, that are located at the base of the brain. The brain stem regulates the central nervous system, and is vital as a conduit for motor and sensory innervations.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• Brainstem, area at the base of the brain that lies between the deep structures of the cerebral hemispheres and the cervical spinal cord and that serves a critical role in regulating certain involuntary actions of the body, including heartbeat and breathing. The brainstem is divided into three...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020