• 26 parts
  • Checked September 2026

Brain Stem Model Labeled, Front and Back

The brainstem as on a classroom model with the cerebellum off: every part named, front and back.

Brain Stem Model Labeled, Front and Back

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
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Write the name of each numbered part.Answer key

  1. Midbrain
  2. Pons
  3. Medulla oblongata
  4. Optic chiasm
  5. Cerebral peduncles
  6. Oculomotor nerve (III)
  7. Trigeminal nerve (V)
  8. Abducens nerve (VI)
  9. Facial nerve (VII)
  10. Vestibulocochlear nerve (VIII)
  11. Pyramids
  12. Olive
  13. Glossopharyngeal nerve (IX)
  14. Vagus nerve (X)
  15. Hypoglossal nerve (XII)
  16. Decussation of the pyramids
  17. Accessory nerve (XI)
  18. Thalamus
  19. Pineal gland
  20. Superior colliculi
  21. Inferior colliculi
  22. Trochlear nerve (IV)
  23. Superior cerebellar peduncles
  24. Middle cerebellar peduncles
  25. Floor of the fourth ventricle
  26. Inferior cerebellar peduncles

Drawn for this site on 2026-09-30 from plain geometry. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

Next step Zoom out: the whole brain

All 26 parts on the diagram

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Regions and tracts 8

  1. Midbrain The smallest of the three regions. Its front is the two cerebral peduncles; its back carries the four colliculi.
  2. Pons Pons is Latin for bridge. The cross fibers on its front run out to the cerebellum on each side.
  3. Medulla oblongata The lowest part of the brainstem. It narrows into the spinal cord.
  4. Optic chiasm Fibers from the inner half of each retina cross here. They cross to the other side of the brain.
  5. Cerebral peduncles Two stalks in the midbrain. The motor fibers from the cortex pass down through them.
  6. Pyramids Two ridges on the front of the medulla. The motor fibers from the cortex run down in them.
  7. Olive A bulge on the front of the medulla, beside the pyramid. It is made by the inferior olive inside.
  8. Decussation of the pyramids Most of the motor fibers cross to the other side here. It marks the border of the medulla and the spinal cord.

Cranial nerve roots 10

  1. Oculomotor nerve (III) It leaves the front of the midbrain. It moves most of the muscles of the eye.
  2. Trigeminal nerve (V) It leaves the side of the pons. It carries feeling from the face and moves the chewing muscles.
  3. Abducens nerve (VI) It moves one eye muscle, the lateral rectus. It leaves at the border of the pons and the medulla, close to the midline.
  4. Facial nerve (VII) It moves the muscles of the face. It leaves at the side of the border between the pons and the medulla.
  5. Vestibulocochlear nerve (VIII) The nerve of hearing and balance. It joins the brainstem just to the side of the facial nerve.
  6. Glossopharyngeal nerve (IX) It leaves the side of the medulla behind the olive. It carries taste and moves muscles of the throat.
  7. Vagus nerve (X) It leaves the side of the medulla behind the olive. It runs to the heart and the organs of the chest and abdomen.
  8. Hypoglossal nerve (XII) It moves the tongue. It leaves the front of the medulla between the pyramid and the olive.
  9. Accessory nerve (XI) Its fibers begin in the top of the spinal cord. It moves two muscles of the neck and shoulder.
  10. Trochlear nerve (IV) It moves one eye muscle, the superior oblique. It leaves from the back of the midbrain, under the inferior colliculi.

The back 8

  1. Thalamus It sits above the midbrain. Nearly all sensory signals pass through it on the way to the cerebrum.
  2. Pineal gland A small gland of the epithalamus. It rests between the two superior colliculi.
  3. Superior colliculi Colliculus means little hill. The upper pair is part of the visual pathway.
  4. Inferior colliculi The lower pair is part of the hearing pathway.
  5. Superior cerebellar peduncles They join the cerebellum to the midbrain.
  6. Middle cerebellar peduncles The biggest of the three. They join the cerebellum to the pons.
  7. Floor of the fourth ventricle Made by the back of the pons and the upper medulla.
  8. Inferior cerebellar peduncles They join the cerebellum to the medulla.

How this list was compiled: Every name and detail checked on 2026-09-30 against OpenStax Anatomy and Physiology 2e: section 13.2 The Central Nervous System (midbrain, pons, medulla, thalamus, pineal gland, colliculi), https://openstax.org/books/anatomy-and-physiology-2e/pages/13-2-the-central-nervous-system; 13.3 (floor of the fourth ventricle), https://openstax.org/books/anatomy-and-physiology-2e/pages/13-3-circulation-and-the-central-nervous-system; 13.4, the table of cranial nerves, https://openstax.org/books/anatomy-and-physiology-2e/pages/13-4-the-peripheral-nervous-system; 14.2 (optic chiasm), https://openstax.org/books/anatomy-and-physiology-2e/pages/14-2-central-processing; 14.3 (cerebral peduncles, pyramids, pyramidal decussation), https://openstax.org/books/anatomy-and-physiology-2e/pages/14-3-motor-responses; 16.5 (the three cerebellar peduncles, the olive), https://openstax.org/books/anatomy-and-physiology-2e/pages/16-5-the-coordination-and-gait-exams. Second source: Wikipedia, text only: Brainstem (where each nerve root leaves), Midbrain, Pons, Medulla oblongata, Optic chiasm, Glossopharyngeal nerve, Vagus nerve, Accessory nerve, Hypoglossal nerve, https://en.wikipedia.org/wiki/Brainstem. Third source for the surface landmarks and the nerve roots: TeachMeAnatomy, The Medulla Oblongata, The Pons, The Midbrain, https://teachmeanatomy.info/neuroanatomy/brainstem/medulla-oblongata/. All wording is our own. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced. Licence: own work

How it works

A brain stem model labeled in two drawings, front and back, with the cerebellum taken off. For brain stem cranial nerves labeled, the front view shows where nerves III and V to XII leave; nerve IV is on the back.

Read the full guide

Front: three regions and their nerve roots

The brackets down the side mark the midbrain, the pons and the medulla oblongata. The oculomotor nerve leaves between the two cerebral peduncles and the trigeminal from the side of the pons. Nerves VI, VII and VIII leave at the groove under the pons. Nerves IX, X and XI leave behind the olive, and XII between the olive and the pyramid.

Back: what the cerebellum hides

With the cerebellum off, the floor of the fourth ventricle shows as a diamond. The cut faces round it are the three cerebellar peduncles on each side. Above them sit the four colliculi, the pineal gland and the thalamus. The trochlear nerve leaves just under the inferior colliculi.

  • Roots III and IV leave the midbrain, V the pons, VI to VIII the groove under the pons, and IX to XII the medulla.
  • Pons is Latin for bridge: its cross fibers run out to the cerebellum on each side.

Questions and answers

What are the three parts of the brain stem?

The midbrain, the pons and the medulla oblongata, from top to bottom. The midbrain sits under the thalamus, and the medulla runs down into the spinal cord.

Which cranial nerves come from the brain stem?

Ten pairs: nerves III to XII. The first two, the olfactory and optic nerves, join the brain farther forward. On a model the ten show as cut roots on the midbrain, the pons and the medulla.

Where do the pyramids cross?

At the decussation of the pyramids, at the bottom of the medulla where it meets the spinal cord. Most of the motor fibers from the cortex cross to the opposite side there.

What are the cerebellar peduncles?

Three stalks of fibers on each side that join the cerebellum to the brain stem: the superior to the midbrain, the middle to the pons and the inferior to the medulla. They show as cut faces once the cerebellum is taken off.

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