CNS Embryology

Embryology! One of my favorite topics. I am absolutely fascinated about how the body grows, folds and divides during the course of development!

The way I approach embryology of an organ is to start with a simple tube and to think about how to manipulate it in order to form the end structure. I can do anything to the it – I can stretch only the middle of the tube equally around the diameter so that the middle becomes wider and the ends taper off, creating a fusiform structure. I can pull on only one side, creating a greater curvature. I can fold, twist, meld and separate to create different parts.

This Daily Doodle shows how a simple tube can be turned into the rudimentary form of the central nervous system. Each color represents a different section of the CNS:

- Red + Orange = Forebrain (aka: prosencephalon)
- Green = Midbrain (aka: mesencephalon)
- Blue = Hindbrain (aka: Rhombencephalon)
- Yellow = Spinal cord

The forebrain is further divided into two parts, the red part which is called the telencephalon and the orange part which is called the diencephalon. The telencephalon grows faster than the diencephalon, which makes the cranial end of the tube shaped like a mickey mouse head. The mickey mouse ears will eventually turn into the two cerebral hemispheres and the diencephalon will form the thalamus, hypothalamus, epithalamus and subthalamus (basically anything with the word “thalamus” in it).

I need to make a part “b” for this daily doodle to show how the tube starts to fold in onto itself to create a more compact and recognizable version of the brain…



  1. O. Oyedele, “Development of the Nervous System”, UBC Year 2 Lecture Notes. January 2012



01/13/12 – “Embrology of Central Nervous System” – Medical Daily Doodle by Michiko Maruyama

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