Internal configuration

  • Prolongation of the ascending and descending tracts of the spinal cord
  • Multiple nuclei and reticular formation

Decussation of the pyramidal tracts

  • Boundary between the medulla oblongata and the spinal cord
  • Cross the median line and move backwards and laterally
  • pyramids --> lateral funiculi of the spinal cord

→ Blurring of the anterior median fissure

Ending of the gracile and cuneate fasciculi

  • Gracile fasciculus → gracile nucleus
  • Cuneate fasciculus → cuneate and accessory cuneate nuclei
  • Cross the median line → medial lemniscus

→ Opening of the central canal backwards: beginning of the fourth ventricle