Pons - External and Internal (White & Grey matter) + QUIZ | Anatomy

Summary

This educational video script delves into the anatomy of the Pons, a critical part of the brainstem. It covers the Pons' external and internal structures, highlighting its role in cranial nerve connections and the arrangement of grey and white matter. The script also discusses the Pons' interaction with other brain regions, emphasizing its importance in motor control and sensory processing.

Takeaways

• 🧠 The central nervous system is divided into the encephalon and the spinal cord, with the encephalon further divided into the brainstem, cerebellum, diencephalon, and telencephalon.
• 🌉 The brainstem includes the medulla, pons, and midbrain, and the pons is the focus of the video, located above the medulla and in front of the cerebellum.
• 👀 The pons has an anterior surface with a basilar sulcus and forms the middle cerebellar peduncles, which connect to the cerebellum.
• 🤖 Several cranial nerves emerge from the anterior part of the pons, including the 5th (trigeminal), 6th (abducens), 7th (facial), and 8th (vestibulocochlear) nerves.
• 🔍 The posterior surface of the pons is covered by the cerebellum and works with the medulla and midbrain to form structures like the rhomboid fossa.
• 📚 Grey matter in the pons contains nuclei, while white matter contains nerve fibers that form tracts.
• 🧬 The pontine nuclei in the basal part of the pons are crucial for the frontopontine tract, which synapses with the pontine nuclei and projects to the cerebellum.
• 🔄 The trapezoid body, formed by crossing fibers of the auditory nerve, divides the internal surface of the pons into the tegmentum and basal part.
• 🚀 Descending tracts in the pons include the corticopontine tracts, which are extrapyramidal and originate from various areas of the cerebral cortex.
• 🌐 Ascending tracts in the tegmentum of the pons include the medial lemniscus, spinal lemniscus, trigeminal lemniscus, and lateral lemniscus, which are involved in sensory perception.
• 🏃‍♂️ Descending tracts in the tegmentum of the pons include the tectospinal, rubrospinal, reticulospinal, and vestibulospinal tracts, which are involved in motor control and coordination.

Q & A

What are the two main parts of the central nervous system?

The central nervous system consists of the encephalon and the spinal cord.

What is the brainstem composed of?

The brainstem is composed of the Medulla, Pons, and Midbrain or mesencephalon.

What is the Pons' location in relation to other brain structures?

The Pons is located above the medulla and in front of the Cerebellum, with the spinal cord below it.

What is the function of the basilar sulcus found on the anterior surface of the Pons?

The basilar sulcus is a prominent groove on the anterior surface of the Pons where it turns backwards toward the Cerebellum, forming the middle cerebellar peduncles.

Which cranial nerve is associated with the lateral extraocular muscles of the eyes?

The 6th cranial nerve, the nervus abducens, is associated with the lateral extraocular muscles of the eyes, aiding in the abduction of the eyeballs.

What is the role of the facial nerve (cranial nerve number 7)?

The facial nerve provides motor innervation for the facial muscles, which helps with facial expressions.

How does the Pons contribute to the formation of the Rhomboid Fossa?

The upper part of the Rhomboid Fossa is formed by the Pons, while the lower part is formed by the medulla.

What is the significance of the Trapezoid Body within the Pons?

The Trapezoid Body is formed by fibers of the cochlear nerve that cross within the Pons to the other side, dividing the internal surface of the Pons into the Tegmentum and the Basilar Part.

What is the primary function of the Pontine Nuclei?

The Pontine Nuclei are significant as they receive synapses from the Frontopontine Tract and then send fibers to the Cerebellum through the middle cerebellar peduncles as the Pontocerebellar tracts.

What type of tracts are found in the Basilar Part of the Pons?

The Basilar Part of the Pons contains only descending tracts or motor tracts, including the Frontopontine tract and the Corticopontine tract.

How does the Tectospinal tract contribute to eye and neck movements?

The Tectospinal tract, originating from the tectum of the Midbrain, is responsible for coordinated eye and neck movements, allowing the neck muscles to unconsciously follow eye movements.

Outlines

00:00

🧠 Introduction to the Pons

The script begins with an introduction to the anatomy of the Central Nervous System (CNS), focusing on the Pons, a part of the brainstem. The CNS is divided into the encephalon and the spinal cord, with the encephalon further divided into the brainstem, cerebellum, diencephalon, and telencephalon. The Pons is situated above the medulla and in front of the cerebellum. The video will cover the external surfaces of the Pons, its topography, and structures visible from anterior and posterior views. It will also explore the internal surface by slicing the Pons to observe the arrangement of grey and white matter. A quiz is mentioned at the end to aid memorization.

05:02

🔍 External Surfaces of the Pons

The script describes the external surfaces of the Pons, which include an anterior and a posterior surface. The anterior surface features the basilar sulcus in the midline and the middle cerebellar peduncles that form the structure connecting to the cerebellum. Several cranial nerves emerge from the anterior part of the Pons, including the 6th (abducens), 7th (facial), 8th (vestibulocochlear), and 5th (trigeminus) cranial nerves, each serving specific functions related to eye movement, facial expression, hearing, balance, and sensory and motor innervation of the face. The posterior surface of the Pons is covered by the cerebellum and lacks distinct structures on its own but works with the medulla and mesencephalon to form structures like the rhomboid fossa, an important landmark for tracts and nuclei.

10:06

🧬 Internal Surface and Grey Matter of the Pons

The script moves on to discuss the internal surface of the Pons, emphasizing the importance of grey matter, which contains cell bodies or nuclei, and white matter, which contains nerve fibers forming tracts. A key landmark, the Trapezoid Body, formed by fibers of the auditory nerve crossing within the Pons, divides it into dorsal (Tegmentum of Pons) and ventral (Basilar Part) regions. The Basilar part contains the Pontine Nuclei, crucial for the frontopontine tract's synapse and the subsequent pontocerebellar tracts to the cerebellum. The Tegmentum houses nuclei for cranial nerves 6-8 and the reticular formation, with small nuclei of the Trapezoid body located between the fibers of the Trapezoid body.

15:07

📚 White Matter Tracts and Summary Quiz

The script concludes with a discussion of the white matter tracts in the Pons, differentiating between descending (motor) tracts in the Basilar part, such as the frontopontine and corticopontine tracts, and ascending (sensory) tracts in the Tegmentum, including the medial lemniscus, spinal lemniscus, trigeminal lemniscus, and anterior spinocerebellar tract. It also mentions the descending tracts in the Tegmentum, like the tectospinal, rubrospinal, reticulospinal, and vestibulospinal tracts, as well as the medial longitudinal fasciculus. The script ends with a challenge for viewers to identify various structures and tracts without labels, suggesting that if they can do so, they have fully grasped the anatomy of the Pons.

Keywords

💡Central Nervous System

The Central Nervous System (CNS) is the part of the nervous system consisting of the brain and spinal cord. It is responsible for receiving, processing, and transmitting information throughout the body. In the video, the CNS is divided into two main parts: the encephalon (which includes the brain) and the spinal cord. The focus of the video is on the Pons, a part of the brainstem within the encephalon.

💡Pons

The Pons is a region of the brainstem located between the medulla oblongata and the midbrain. It plays a critical role in various functions, including sleep, respiration, and eye movement. The video script describes the Pons' external and internal surfaces, its relationship with cranial nerves, and its role in transmitting signals between different parts of the brain.

💡Brainstem

The brainstem is a part of the brain that connects to the spinal cord and is situated beneath the cerebrum. It is composed of three parts: the medulla, the pons, and the midbrain. The video script emphasizes the Pons' role within the brainstem, particularly its connection with the medulla and the midbrain.

💡Cerebellum

The Cerebellum is a region at the back of the brain that plays a crucial role in motor control, coordination, and balance. The script mentions that the Pons is located in front of the Cerebellum and forms the middle cerebellar peduncles, which are crucial for communication between the Pons and the Cerebellum.

💡Basilar Sulcus

The Basilar Sulcus is a groove found in the midline of the anterior surface of the Pons. It is a topographical landmark that helps in identifying the Pons' anterior surface. The video script describes the Basilar Sulcus as part of the Pons' external surface anatomy.

💡Cranial Nerves

Cranial nerves are the nerves that emerge directly from the brain, as opposed to the spinal cord. There are 12 pairs of cranial nerves, each with distinct functions. The video script identifies several cranial nerves that emerge from the Pons, including the trigeminal (5th), abducens (6th), facial (7th), and vestibulocochlear (8th) nerves.

💡Rhomboid Fossa

The Rhomboid Fossa is a part of the fourth ventricle of the brain, located between the pons and the medulla. It is an important landmark for tracts and nuclei. The script mentions that the upper part of the Rhomboid Fossa is formed by the Pons and the lower part by the medulla.

💡Grey Matter

Grey Matter refers to areas of the brain and spinal cord where the cell bodies of neurons are concentrated. It appears grey because it has less myelin compared to white matter. The script explains that grey matter in the Pons contains nuclei and is crucial for the formation of various tracts and communication pathways.

💡White Matter

White Matter consists of nerve fibers (axons) that are covered by a myelin sheath, giving it a whitish appearance. It is responsible for transmitting signals throughout the brain and spinal cord. The video script describes how white matter in the Pons is organized, including tracts such as the corticopontine and pontocerebellar tracts.

💡Pontine Nuclei

The Pontine Nuclei are clusters of neurons located within the Pons. They are part of the extrapyramidal motor system and play a role in the coordination of movement. The script explains that the Pontine Nuclei receive fibers from the corticopontine tract and project to the Cerebellum via the pontocerebellar tracts.

💡Trapezoid Body

The Trapezoid Body is a bundle of nerve fibers found within the Pons, formed by fibers of the cochlear nerve that cross to the opposite side. It divides the internal surface of the Pons into dorsal and ventral parts. The script uses the Trapezoid Body as a landmark to explain the internal organization of the Pons.

Highlights

The central nervous system is composed of the encephalon and the spinal cord.

The encephalon is divided into the brainstem, cerebellum, diencephalon, and telencephalon.

The brainstem includes the medulla, pons, and midbrain.

The pons is located above the medulla and in front of the cerebellum.

The external surfaces of the pons include an anterior and a posterior surface.

The anterior surface of the pons features the basilar sulcus and the middle cerebellar peduncles.

Cranial nerves VI, VII, and VIII emerge from the anterior part of the pons.

The posterior surface of the pons is covered by the cerebellum.

The rhomboid fossa is formed by the pons and the medulla.

Cerebellar peduncles are found on the posterior surface of the pons.

The internal surface of the pons is divided into the tegmentum and the basilar part.

The pontine nuclei are located in the basilar part of the pons.

The trapezoid body is formed by fibers crossing within the pons.

The tegmentum of the pons contains nuclei for cranial nerves 6-8.

The reticular formation is present in all parts of the brainstem, including the pons.

The pons contains both ascending (sensory) and descending (motor) tracts.

The corticopontine tract is an example of an extrapyramidal tract.

The medial lemniscus is an ascending tract that carries sensory information to the cerebral cortex.

The tectospinal tract is involved in coordinated eye and neck movements.

The rubrospinal tract supports and coordinates voluntary movement.

The reticulospinal tract is responsible for balance and posture.

The medial longitudinal fasciculus coordinates involuntary head and eye movements.

Transcripts

What’s up, Meditay here; let’s continue  the anatomy of the Central Nervous System.  

In this segment, we’ll cover  the complete anatomy of Pons 

So the central nervous  system consists of two parts:  

the encephalon and the spinal cord. The encephalon  is then further divided into specific parts. 

We have the brainstem, which consists of  the Medulla, Pons, and the Midbrain or the  

mesencephalon. We have the Cerebellum back here,  then the diencephalon and the telencephalon. 

Our focus in this video is  going to be Pons, which is here. 

So in this video, we’re first going to cover  the external surfaces of the Pons. Basically,  

look at its topography and what structures you’ll  find from an anterior view and a posterior view.  

Then we’re gonna slice up the Pons and look at  the internal surface. Basically, see how the grey  

matter and white matter are arranged within it. Then I’ve made a little quiz at the end which  

might help you if you need to memorize. Alright, so we can start by replacing  

this picture with a more realistic one. Pons is located here, lying right above  

the medulla and in front of the Cerebellum.  And down here, you can see the spinal cord. 

Now, if we remove a part of the cerebral  cortex, you’ll be able to see the rest of Pons.  

As well as the mesencephalon, or the Midbrain,  which is the most superior part of the brainstem. 

Alright. Now. Externally, your Pons has two  surfaces. It has an anterior surface and  

a posterior surface. Let’s now cover the  typical morphology of these two surfaces,  

starting with the anterior surface first.  And we’ll do that by looking at the brainstem  

from this perspective; we’ll see this. So again,  Pons is this prominent bulb you see here. In the  

midline of the anterior surface, there s a sulcus  called the basilar sulcus. Laterally on either  

side, you’ll see that Pons turns backwards toward  the Cerebellum. And that is because Pons forms  

the middle cerebellar peduncles on either side,  which continue into the Cerebellum back there. 

That was the general morphology  of the anterior surface of Pons,  

but there are some cranial nerves that  leave the brainstem at this area. We  

have 12 cranial nerves in our body, and each  serves its particular function in the brain,  

but from the anterior part of the Pons. You’ll  see a nerve that goes out between the Pyramids  

of medulla oblongata and Pons. This nerve is  the 6th cranial nerve, the nervus abducens,  

that go to the lateral extraocular muscles of the  eyes to help with the abduction of the eyeballs.  

Then, between the Olives and the middle cerebellar  peduncle, you’ll find cranial nerve number 7. The  

facial nerve, which provides motor innervation  for the facial muscles, helps with facial  

expressions. And cranial nerve number 8, the  vestibulocochlear nerve for hearing and balance. 

The last nerve is at the surface of Pons. And that  is the 5th cranial nerve, the nervus Trigeminus.  

It’s a very large nerve that  goes to your facial region  

to provide sensory innervation, motor innervation,  as well as parasympathetic innervation for glands. 

So all of these nerves emerge  from the anterior area of Pons. 

Now let’s turn this model around and look at the  posterior surface. From the posterior view, you’ll  

see that the Cerebellum covers the whole posterior  area of Pons. SO let’s go ahead and remove it. 

So Pons is here, above the medulla and  below the Midbrain, or mesencephalon.  

Pons doesn’t really have any specific structure on  its own. Rather it works with the medulla and the  

mesencephalon in forming certain structures. One  of them is the Rhomboid Fossa. The rhomboid fossa  

has many nuclei for the cranial nerves and is a  very important landmark for tracts and nuclei.  

I’ll cover this in detail in my next video. But  for now, I want you to know that the upper part  

of the rhomboid fossa is formed by Pons, and  the lower part is formed by the medulla. Cool. 

On either side of the rhomboid fossa, you’ll  see the cerebellar peduncles, which contain  

fibers that run between the Cerebellum and  all three parts of the brainstem. The inferior  

cerebellar peduncle contains fibers that go to the  medulla. The middle cerebellar peduncle contains  

fibers that go to Pons. The superior cerebellar  peduncle contains fibers that go to the Midbrain.  

So that was all for the posterior surface of Pons. Now let’s go over to the next segment of this  

video, and look at the internal surface of Pons. But before we do that, I want you to keep in mind  

that grey matter always contains cell bodies,  so all structures within the grey matter  

are nuclei. White matter contains  nerve fibers that form tracts. 

Now let’s take Pons, and slice it up like  this to look at the internal surface. 

So this is an outline of what Pons looks like.  We’ll see the Basilar Sulcus here, so this is  

the anterior surface. We’ll also see the middle  cerebellar peduncles and the Rhomboid Fossa back  

here. I hope it makes sense at this point. Before  we dig into structures on the surface of Pons,  

we need to go through an important landmark that  we use to separate Pons into two parts. So here we  

see the internal part of the ear. The inner ear  we call it with the cochlea and the vestibulum.  

The cochlea, which is our primary organ of  hearing, has a nerve called the cochlear  

nerve. The cochlear nerve will go directly towards  Pons and then ascend towards the superior temporal  

gyrus as the Lateral Lemniscus. But some fibers  cross to the other side and then ascend to the  

superior temporal gyrus as the lateral lemniscus.  Now, why am I telling you this? Because as these  

fibers cross within Pons to the other side,  they form the Trapezoid Body, as you see here.  

And the Trapezoid body divides the internal  surface of Pons into two regions. The Dorsal part  

becomes the Tegmentum of Pons, and the Ventral  Part becomes the Basilar Part. Let’s now go  

through the Grey matter in Ventral and Dorsal  parts, then do the white matter, so we’ll start  

with the gray matter structures associated  with the Basilar part first. The only grey  

matter in the Basilar part are the Pontine Nuclei These Pontine nuclei are a very significant part  

of Pons because, there’s gonna be a tract that  originates outside of the primary motor cortex,  

from the frontal lobe of the  cortex, called Frontopontine Tract. 

It will descend and synapse with the pontine  nuclei, as you see here. Then once they synapse,  

these fibers will go to the Cerebellum  through the middle cerebellar peduncles, as  

the Pontocerebellar tracts. So these fibers cross  to the other side and then go to the Cerebellum. 

Once they’re at the Cerebellum, the tracts  will then travel towards the Red nucleus  

of the Midbrain as the cerebellorubral tract  and then descend as the rubrospinal tract to  

support voluntary movements. So the Pontine  nuclei are a very important part of Pons. 

The grey matter of the Tegmentum consists of  nuclei that belong to cranial nerves number  

6-8 in the Rhomboid Fossa. We’ll cover the  rhomboid fossa in detail in a separate video,  

but for now, we’ll stick with the most important  structures associated with Pons to really  

understand the anatomy of it. Next, we’ll see the  reticular formation. You’ll find the reticular  

formation along all parts of the brainstem. Then between the fibers of the trapezoid body,  

you’ll find small nuclei called  the nuclei of the Trapezoid body,  

which some of the fibers synapse with. So that was all the grey matter of Pons. Now  

let’s go ahead and cover the white matter of  the Basilar Part and the Tegmentum of Pons.  

We’ll start with the basilar part. Here you’ll only find descending tracts or motor  

tracts. Remember earlier when we talked about  the frontopontine tract and the pontocerebellar  

tracts? Where fibers from the frontal cortex go  down to synapse with the pontine nuclei in Pons,  

and then fibers go from Pons to the Cerebellum  as pontocerebellar tracts? Pontocerebellar tracts  

are descending tracts, so we’ll need to colour  it as red. The other descending tracts you see  

here is the frontopontine tract, you’ll see  it depending on at which level you cut Pons. 

But, the frontopontine tract is a part of a bigger  bundle of tracts called the Corticopontine tract.  

The Frontopontine tract was just an example. If  the tract originates from the occipital lobe,  

it’s called occipitopontine tract. If  it originates from the temporal lobe,  

it’s called temporopontine tract. And so  on. That’s why I specifically said frontal  

lobe earlier because the frontopontine  tract comes from the frontal cortex.  

Notice that they all originate from  different areas of the cerebral cortex,  

which are outside of the primary motor area of  the brain. And because of that, these tracts  

are considered extrapyramidal tracts. Because  they don’t originate from the pyramidal cells of  

the primary motor cortex. So when we use the term  Corticopontine tract, you’re really talking about  

the frontopontine tract, occipitopontine tract,  temporopontine tract, and Parietopontine tract. 

So you’ll find the corticopontine tract fibers  here synapsing with the pontine nuclei. Awesome. 

The other descending tract is a pyramidal tract,  called the Corticospinal tract. It’s a pyramidal  

tract because it comes from the pyramidal cells of  the primary motor area in the cortex and descends  

down to the spinal cord to innervate skeletal  muscles. Alongside the corticospinal tract, you’ll  

find corticonuclear tracts as well. It descends  in the same areas as the corticospinal tract,  

but the corticonuclear tracts are responsible for  the voluntary control of muscles located in the  

head and neck. So that was all the white matter of  the basilar part—only descending tracts. Now let’s  

do the white matter in the Tegmentum of Pons. The  first one is the medial lemniscus. Now we need to  

repeat a few things in order to remember this one. So here is the cross-section of the spinal cord  

and the medulla. Remember that there were fibers  that came from the Lower parts of the body, which  

ascend as Gracile fascicle and sensory fibers  that came from the upper parts of your body, which  

ascend as Cuneate fascicle? I use the G in Gracile  Fascicle as Genitals to remember that it comes  

from the lower parts of the body. So these fibers  receive conscious proprioceptive information,  

as well as sensory input from mechanoreceptors,  and they ascend to the gracile and cuneate nuclei  

in the medulla. Then fibers there will  leave as either the external arcuate fibers  

or internal arcuate fibers. The internal arcuate  fibers cross to the other side, and then they will  

ascend as the medial lemniscus, which is what  you see here in Pons. They will ascend and go  

to the primary somatosensory area in the cerebral  cortex so that you’re aware of sensory touch and  

vibration, as well as the position of your  body parts. So that is the Medial Lemniscus. 

Then we have the Spinal Lemniscus. Remember when  we talked about the cross-section of the medulla,  

we had two spinothalamic tracts? One lateral  and one anterior? They ascend together as the  

spinal lemniscus, and that’s what you see  here in Pons. So it ascends to the cortex,  

to the primary somatosensory area as well. And  they’re responsible for conscious sensory input  

of Pain temperature, Pressure,  and touch. So that is this one. 

Next, we have the Trigemnical Lemniscus. The  trigemnical lemniscus comes from the trigeminal  

ganglion, which is a part of the trigeminal nerve,  the 5th cranial nerve. So Pons receives sensory  

input from this nerve, and then it crosses to the  other side and ascent to the primary somatosensory  

area. So that is the trigeminal lemniscus. Then we have the Anterior spinocerebellar tract.  

Remember when we talked about the medulla, that  we have posterior and anterior spinocerebellar  

tracts? The posterior spinocerebellar tract  will go through the inferior cerebellar peduncle  

to go to the Cerebellum. But the anterior  one will go through Pons and the Midbrain  

and then go to the Cerebellum through the  superior cerebellar peduncle. And that’s why  

we see it here because it’s going up to the  midbrain to eventually go to the cerebellum. 

Then, I wanna repeat something I mentioned earlier  in this video. About the auditory nerve called the  

cochlear nerve that goes to the Pons and then  ascends as the lateral lemniscus to go to the  

superior temporal gyrus, which is the primary  auditory area of the brain. Some fibers cross  

and then ascend to the superior temporal gyrus.  And the fibers that cross form the trapezoid  

body. But when they ascend after crossing, they  also ascend as the lateral lemniscus, which is an  

ascending tract that we need to include as  well. So that was all the ascending tracts in  

the Tegmentum of Pons. Remember, blue represents  sensory or ascending tracts, and red represents  

descending or motor tracts. Now let’s do all  the descending tracts in the Tegmentum of Pons.  

And the first one is the Tectospinal Tract The tectospinal tract is called tectospinal  

because these fibers come from the tectum of the  Midbrain. So here is the Midbrain. Posteriorly,  

you’ll find the tectum. So the tectospinal  tract descend from here. And these are fibers  

that are associated with coordinated eye and  neck movements. And remember, since this tract  

originates from the brainstem it is referred to as  an extrapyramidal tract. Hence, it unconsciously  

moves your neck muscles with your eyes. So when you look at something.  

Imagine you’re looking at a hamburger, you look at  it, and you keep looking at it as it passes you,  

and your neck muscles unconsciously follow  your eyes. That’s what this tectospinal  

tract is responsible for. And that is our  first descending tract of the tegmentum.  

The next one is called the Rubrospinal tract. Remember we talked about the corticopontine tract,  

which are fibers that originate from anywhere  outside of the primary motor area that descends to  

synapse with the pontine nuclei? These fibers will  go to the Cerebellum as the pontocerebellar tract.  

From the Cerebellum, fibers will go  to the Red nuclei of the Midbrain,  

as the cerebellorubral tract. And then they will  descend as the rubrospinal tract. Notice that I  

said these fibers do not originate from the  pyramidal cells of the primary motor cortex,  

that’s why they’re referred to as extrapyramidal  tract. They don’t initiate movement,  

but they support and coordinates the voluntary  movement. So that is the rubrospinal tract. 

Next, we have the reticulospinal tract, which is a  part of the balance and posture system. They come  

from the reticular formation inside the brainstem.  The Reticular system are responsible for Sleep,  

alertness, cardiovascular control, breathing  and all of those vital things. But they’re also  

responsible for motor control like your balance  and posture through the reticulospinal tract.  

So that is this one. Next, we  have a vestibulospinal tract 

And to understand this one, we need to involve  the inner ear again, because the inner ear has  

the vestibular system. The vestibular system has  crystals within it that monitors your balance. And  

it transmits impulses to your brain, and then down  to your muscles so that you can keep your balance.  

So whenever your head is tilted or you’re  upside down, or you’re about to fall,  

all of that is monitored and controlled by your  vestibular system. So it helps with balance and  

posture. Alright, let’s just clean up the labels  and add a little color to differentiate them.  

There is one more tract that we need to mention,  which is the medial longitudinal fasciculus,  

which descends and is present only in  the cervical segments in the spinal cord.  

This tarct coordinated involuntary movements of  the head neck and eyes through synapses between  

the cranial nerves 3, 4, 6, and 11. So that was  all I had for the internal surface of the Pons. 

I made this table for the nuclei and tracts we’ll  find along the basilar part and the Tegmentum of  

Pons along with a little description of them.  Now, this Is where this video gets scary.  

I am going to make all of these names disappear,  and can you, from the beginning, tell me what is  

the name of number 1, what is the name of number  4, where does number 14 go and where does number  

12 go. If you can do that, then you’ve grasped  the anatomy of the Pons fully. If you found this  

video helpful, please put a like, comment,  share, whatever you find convenient to you. 

The next video is going to be about the  Fourth Ventricle and the Rhomboid Fossa.