Neuroanatomy - anatomy.tv worksheet

Midbrain

The midbrain is a small part of the brain and is often overlooked. It connects the hindbrain to the forebrain and makes up part of the brainstem, together with the hindbrain.

The anterior or ventral part of the midbrain is called the tegmentum. There is a mass of fibres in front of it called the cerebral peduncles (don’t get them mixed up with the cerebellar peduncles). These are sometimes called the crus cerebri.

If we look at the posterior or dorsal aspect we can see a different part. What is it called? What does it do? If you answer that you'll see that for a part of the brain that is often brushed over, it's pretty important.

The midbrain (anatomy.tv)

Posterior structures

Now we can get onto the five rounded blobs on the dorsal part of the midbrain.

The rounded lump in the middle is anatomically part of the epithalamus (and hence part of the forebrain, so there's room for confusion here - sorry I mean discussion). It is sometimes called the epiphysis cerebri, but is more commonly called what?

What type of gland is it? What does it release?

It has an important function in managing your 24 hour clock and is often calcified in adults, which makes it stand out in radiological images.

The surrounding lumps are the colliculi. There are superior and inferior colliculi on either side, and to keep a long story short, one pair is involved with information from the ear and one pair with information from the eye. Which is which?

The midbrain also houses the nuclei of CN III and CN IV.

The posterior midbrain (anatomy.tv)

A different view

See if you can identify the same parts on this model. Not all are annotated but you should be able to figure it out.

The medulla oblongata (anatomy.tv)