Anatomy · Neuroanatomy

Brainstem: external features, internal organization and major pathways

7 min read

  • Brainstem: stalk-like part of the brain connecting the spinal cord to the forebrain; comprises medulla oblongata, pons and midbrain, lying in the posterior cranial fossa on the clivus.
  • Continuous with the spinal cord below (medulla) and cerebral hemispheres above (midbrain); separated from the cerebellum posteriorly by the fourth ventricle.

Functions of the Brainstem

  • Functions:
    • Passage for ascending and descending tracts
    • Vital centres (cardiac, vasomotor, respiratory)
    • Reticular activating system for consciousness
    • Nuclei of cranial nerves III to XII
  • The pontine respiratory centre modulates the output of the respiratory centres in the medulla.

External Features

External features of the brainstem, by part