Hello all it is your friend Dr. Alsup again and we are going to discuss the basic structures
of the brain and I can't emphasize enough how we are only discussing the very basics of the brain.
You will get more detail in other areas of the curriculum but there are certain basic
structures of the brain you must know to best understand the relationships with the surrounding
neurovasculature which is an emphasis of this session. So let's look at the brain
in many different views and we are going to start with a lateral view. The largest component
so basically everything I'm outlining right here, is going to be the cerebrum.
Not the cerebellum these names are very close, cerebrum the shorter name
and when you're looking at a lateral view you can only see one of the two cerebral hemispheres.
But even when only looking at one it is still the dominant feature the hemispheres will be further
subdivided into cerebral lobes which are used for descriptive purposes and while they're named after
bones they do not correspond precisely with their similarly named bone. So as long as you understand
the general areas of the lobes we will be happy. So the frontal lobe is going to be the most anterior
and I know this is more anterior because the cerebellum is back here and the cerebellum is
always posterior. So the frontal lobe is going to be more anteriorly placed. The parietal lobe will
be kind of intermediate and superior. The occipital lobe will be posterior and the temporal lobes will
be more inferiorly located on the cerebrum below this lateral sulcus right here.
You can also nicely see the cerebellum here and it's going to be posterior to the brain
stem so this is the cerebellum right here. You can see a bit of the brainstem here
but it is a bit out of focus and some of the vasculature associated as well.
Moving to a superior view all you can see is the cerebrum so all cerebrum all the time
and you can actually see both of the hemispheres here separated by this dominant
longitudinal cerebral fissure that's going to separate the two hemispheres.
Recall that the fox cerebri is going to sit here during life.
So just basics the frontal lobe is going to be anteriorly placed with the parietal lobes kind of
intermediate and you can only see just a little bit of the occipital lobe in a superior view.
Now looking at an anterior view of the brain again the dominant structure is the cerebrum
with the longitudinal fissure running down between the two hemispheres. You can see the frontal lobes
very well on a anterior view and the temporal lobes you can see kind of towards the sides
here and a bit more inferiorly placed. And what's really cool in this when we get into this view
is you can start seeing some of the structures of the brain stem specifically you can see the pons
right here with the basilar artery running kind of right on top of it and you can even see a
bit of the medulla oblongata with the vertebral arteries running on either kind
of on top of it as well you can see the vertebral arteries here actually very different in terms of
caliber or size. So these vertebral arteries are blocking a good amount of the view of the medulla.
Moving to an inferior view of the brain this will be anterior and this will be posterior
and I know that because you can see the cerebellum here, cerebellum is always posterior.
Of the cerebrum you have a nice view of the inferior portions of the frontal lobes.
And what's being retracted here with these tools right here are going to be the
temporal lobes of the cerebrum and kind of spread a little bit further than what is natural
you have the longitudinal fissure running right in this region and the reason that there's been
kind of movements of these lobes is in order to better view the vasculature in this region.
You can see portions of the brainstem you can only see a little bit in terms of the midbrain
in this region but you have a very nice view of the pons right here with that basilar artery again
that we'll talk about in more detail in the arteries video. And then you can see the medulla
oblongata with the vertebral arteries kind of sitting right on top of it as well.
And lastly we can see the cerebellum it is going to be inferior to the cerebrum
and posterior to the brain stem and we can finally see the two cerebellar hemispheres
right here and right here so those are going to be the two hemispheres of the cerebellum.
Lastly let's look at a hemisected brain which literally means the brain was cut right down the
middle into right and left halves and now we are looking inside the brain so seeing
some of those deeper structures. You can see the cerebrum here so including the corpus callosum in
this region as well as the cerebellum in this region so you see those two largest structures of
cerebrum and the cerebellum. Right in this portion here is where you have the diencephalon and this
isn't on your list of structures but I did want to at least mention where this is located. This
is kind of that central core of the brain and is not visible at all from an external view. And then
with this hemisected brain you can really start seeing the brain stem in a little bit more detail
specifically we're actually able to see the midbrain which is kind of this portion right
here. And then you're going to have the pons and then lastly you will have the medulla so the
more distantly oriented or caudely-oriented is the medulla oblongata and if we were to
move more distally at that point we would be getting into the spinal cor. So if your
foramen magnum is say right here you have that transition from the medulla to the spinal cord.
All right so that is what we want you to identify on the brain in the anatomy curriculum. Knowing
these basics will really help with the vasculature as well as the cranial nerves. As always feel free
to reach out with any questions and I thank you for your time and attention