• 13 parts
  • Checked October 2026

Label the Portions of the Prenatal Brain

The brain of the embryo as a tube with swellings: tap a ring to read what each vesicle becomes.

Label the Portions of the Prenatal Brain

Name Date

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1 2 3 4 5 6 7 8 9 10 11 12 13
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Write the name of each numbered part.Answer key

  1. Forebrain (prosencephalon)
  2. Midbrain (mesencephalon)
  3. Hindbrain (rhombencephalon)
  4. Spinal cord
  5. Telencephalon
  6. Diencephalon
  7. Mesencephalon (midbrain)
  8. Metencephalon
  9. Myelencephalon
  10. Optic vesicle
  11. Cephalic flexure
  12. Pontine flexure
  13. Cervical flexure

Drawn for this site on 2026-10-01 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 Next: the finished brain these vesicles become

All 13 parts on the diagram

Show the list

Three vesicles 4

  1. Forebrain (prosencephalon) The front primary vesicle, also called the prosencephalon. It later divides into the telencephalon and the diencephalon.
  2. Midbrain (mesencephalon) The middle primary vesicle, also called the mesencephalon. It stays one vesicle when the other two divide.
  3. Hindbrain (rhombencephalon) The rear primary vesicle, also called the rhombencephalon. It runs on into the spinal cord and later divides into the metencephalon and the myelencephalon.
  4. Spinal cord The narrow rest of the neural tube. It runs on from the hindbrain.

Five vesicles 9

  1. Telencephalon The front part of the forebrain. It becomes the cerebral hemispheres, the cerebrum.
  2. Diencephalon The rear part of the forebrain. The thalamus forms from it.
  3. Mesencephalon (midbrain) The midbrain, at the top of the bend. Its cavity becomes the cerebral aqueduct.
  4. Metencephalon The upper part of the hindbrain. It turns into pons and cerebellum.
  5. Myelencephalon The lower part of the hindbrain. It becomes the medulla oblongata.
  6. Optic vesicle A pouch that grows out of the forebrain. It goes on to form the retina of the eye.
  7. Cephalic flexure The first bend, at the midbrain. It folds the forebrain down in front.
  8. Pontine flexure The bend at the future pons. It bends the opposite way to the other two.
  9. Cervical flexure The bend where the hindbrain meets the spinal cord.

How this list was compiled: Every name checked on 2026-10-01 in at least two of these. (1) Wikipedia, English edition, Brain vesicle, Flexure (embryology) and Development of the nervous system in humans, https://en.wikipedia.org/wiki/Brain_vesicle. (2) Henry Gray, Anatomy of the Human Body, 20th edition (1918), Development of the Nervous System, https://archive.org/details/anatomyofhumanbo1918gray. (3) UNSW Embryology, Neural System Development, https://embryology.med.unsw.edu.au/embryology/index.php/Neural_System_Development. Detail lines are in our own words. Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work

How it works

Before birth the brain starts as the front end of a hollow tube. Two drawings of the developing brain show it from the side, first with three swellings and then with five.

Read the full guide

Three vesicles first

Rings 1 to 3 are the primary vesicles from front to back: the forebrain or prosencephalon, the midbrain or mesencephalon and the hindbrain or rhombencephalon. Ring 4 is the narrow tube behind them, the spinal cord.

Then five, on a bent tube

The forebrain has divided into the telencephalon and the diencephalon, and the hindbrain into the metencephalon and the myelencephalon. The midbrain stays one piece at the top of the arch. Each curved arrow marks a bend: the cephalic flexure under the midbrain, the pontine flexure behind it and the cervical flexure beside the spinal cord.

  • Front to back the five run telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon.
  • Only the first and the last primary vesicle divide; the middle one does not.

Questions and answers

What are the three primary brain vesicles?

The prosencephalon or forebrain, the mesencephalon or midbrain and the rhombencephalon or hindbrain. They are three swellings at the front end of the neural tube, and the hindbrain runs on into the spinal cord.

What are the five secondary brain vesicles?

The telencephalon and diencephalon, which come from the forebrain; the mesencephalon; and the metencephalon and myelencephalon, which come from the hindbrain. Sources put three vesicles at about the fourth week of development and five in the fifth.

What does each brain vesicle become?

The telencephalon becomes the cerebrum. The thalamus forms from the diencephalon. The mesencephalon stays the midbrain. The metencephalon turns into pons and cerebellum; the myelencephalon turns into the medulla oblongata.

Is this the figure for "label the following picture of a developing brain"?

No. That line comes from a publisher's homework set, and its picture is theirs. These two drawings are our own and show the same vesicles, so you can practice the names here. We have no answer key for any homework set.

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