German Contact Help Login Register

Superior view of base of the skull

Structures seen on the superior view of the base of the skull.

Show transcript

Hello, everyone! This is Joao from Kenhub, and welcome to another anatomy tutorial where, this time, I'm going to be talking about the superior view of the base of the skull.

So what I'm going to be doing here on this tutorial is looking at the superior view of the skull, as you can see here on the image of the screen. We’re going to be describing the different structures that you can see from this view.

Now, I'm going to just quickly list them before we move on and talk about them in a little bit more detail. So we’re going to be seeing bones, different fossae, foramina, canals, some sulci can be seen as well, and other structures that are related to different bones that are seen here from this view.

Now, let’s continue on to the different bones and related structures that can be seen from the superior view of the base of the skull.

The first bone is this one that you see here, highlighted in green. This is known as the sphenoid bone, which is sometimes referred to as the “wasp bone” due to its shape.

It makes up the middle part of the base of the skull and is comprised of four parts. Three of which we can clearly see from the superior view of the base of the skull, which is the body. You can see it here. This is the body of the sphenoid. You also see the two greater wings, here, and the two lesser wings, as you can clearly see here.

Now, you cannot see the pterygoid processes. We can only see them from an inferior or lateral view of the skull. But I just wanted to add here to the list so you know that the sphenoid bone is comprised of these four main parts.

Now, we’re going to focus on this one that you see here, highlighted in green. These are the greater wings of the sphenoid bone.

And the greater wings of this bone arise from… or arise posterolaterally from the body of the sphenoid.

There are three important openings or foramina visible on the greater wings from this aspect. One of them is the foramen rotundum through which the maxillary nerve passes through.

There is also the foramen ovale through which the mandibular nerve and the accessory meningeal artery pass through.

And the other one is known as the foramen spinosum. Here, the middle meningeal vessels and also the meningeal branch of the mandibular nerve pass through.

Now, we’re going to take a closer look at these different foramina on... or later on on this tutorial. We’re going to highlight them and see them. But just keep in mind that they are found on the greater wing of the sphenoid bone.

Another important point to make here is that the lateral and anterior surfaces of the sphenoid bone make up the infratemporal surfaces and lateral walls of the orbit respectively.

Now, another structure that we find or two structures that we find on the sphenoid bone that are now seen here, highlighted in green, are the lesser wings of the sphenoid.

Now, the lesser wings of this bone form the optic canal through which the optic nerve and ophthalmic artery pass through. Now, the lesser wings contribute to the formation of the lateral margin of the orbit and part of the cranial cavity.

Now, the structure that we’re now highlighting, which we would also talk about briefly on that initial list, this is known as the body of the sphenoid. And being the most centrally located part of the sphenoid bone, the body contributes to the formation of the nasal cavity and the medial wall of the optic canal.

Important structures found on the body of the sphenoid include some structures that we will be highlighting and talking a little bit more later on on this tutorial. But these include the sella turcica, which houses an important structure, an important gland known as the pituitary gland.

There’s another fossa known as the hypophyseal fossa, the dorsum sellae, and the sphenoidal sinuses. But we’re going to be looking at some of these structures later on.

Now, let’s start with one of those structures that I just mentioned before, seen here, highlighted in green. This is known as sella turcica which is, then, located on the body of the sphenoid. And owing to its saddle shape, the sella turcica was given its name which means “Turkish chair.”

Now, the sella turcica houses an important gland in your body known as the pituitary gland.

We’re moving on to another highlight, another structure that I briefly mentioned about when we talked about the body of the sphenoid, this is the tuberculum sellae. This is an elevation on the sphenoid bone in the area where the sella turcica is found. It is sometimes referred to as the tubercle of the sella turcica.

The next structure which we will highlight, this is the dorsum sellae. The dorsum sellae is located on the body of the sphenoid as well, posterior to the sella turcica. It forms the posterior boundary of this structure, the sella turcica.

The next one is this one that you see, highlighted in green. This is the hypophyseal fossa. This is a depression found on the body of the sphenoid bone and is part of the sella turcica. This is where the pituitary gland sits.

We’re going to move on to another structure or two… or a set of two structures known as the anterior clinoid processes. And the anterior clinoid processes are formed by the lesser wing of the sphenoid bone. And these processes provide attachment for the tentorium cerebelli.

The next one that we’re going to be highlighting here, this is known as the jugum sphenoidale, which is a portion of the body of the sphenoid located between the two lesser wings of the sphenoid and anterior to the sella turcica. It forms part of the anterior cranial fossa.

And since we have anterior clinoid processes, we should also have what you see here, highlighted in green. These are, then, the posterior clinoid processes of the sphenoid bone which are two eminences located on the posterior part of the sella turcica. Now, the tentorium cerebelli attaches to these two eminences.

The other structure that we are going to be highlighting now, this is known as the clivus. The clivus is a slope located posterior to the body of the sphenoid bone just behind the dorsum sellae.

We’re going to be highlighting another bone that you can see from the superior view of the cranial base. This is known as the ethmoid bone. You can only see some parts of this bone here from this view. And, of course, there are many other parts that you can see from different perspectives. So I suggest you see other tutorials here at Kenhub where we explain… we explore the skull from different perspectives. And you can get a better understanding about the ethmoid bone.

Now, but just for an overview here, the ethmoid bone contributes to the formation of these different structures on the skull including the orbit, the nasal cavity, the nasal septum, and the floor of the anterior cranial fossa.

Now, it comprises the perpendicular plate, two ethmoidal labyrinths attached to the cribriform plate, and an orbital part.

And one of the structures that we can see here—and we’re going to be highlighting—that belongs to the ethmoid bone is the cribriform plate. And it lies within the ethmoidal notch of the frontal bone.

And the cribriform plate forms the roof of the nasal cavity. And it has many openings through which olfactory fibers from the nasal cavity pass through the, then, the anterior cranial fossa.

Now, the word cribriform in Latin means “perforated.” And you can clearly see here on this image that there are a lot of tiny holes where the different olfactory fibers will pass through and reach the anterior cranial fossa.

The other structure that we’re going to be highlighting here, this belongs to the frontal bone now. This is known as the frontal crest. The frontal crest is located on the frontal bone, as I mentioned, on the internal surface. From this aspect, we see the notch.

Now, the other structure that we’re going to be highlighting here, this is known as the superior surface of the orbital plate. On the superior surface of the orbital plate, we find depressions formed by the frontal lobes of the brain.

Upon closer inspection, when we have a closer look here, grooves for the meningeal branches for the ethmoidal vessels can be also seen.

And you can see a little bit here, as you notice here, that the vessels are forming these impressions, the ethmoidal vessels.

One bone that we can clearly see here—and I'm going to highlight it fully—this is, then, the frontal bone. The frontal bone can be divided into three parts. Of course, we’re not going to be seeing all of them here. This is… this is only one view of this bone. We have to explore from different views as well.

But these include the squamous part, the orbital part, and also a nasal part.

The squamous part encompasses the area of the forehead and is the largest part of the frontal bone. It makes up the frontal sinuses, while the orbital part forms the ethmoidal sinuses and part of the roof of the orbit.

The stem of your nose is formed due to the adherence of the nasal part of the frontal bone with the frontal processes of other bones like the maxilla and nasal bones.

Again, you can see all of these from different perspectives, so I suggest you start exploring other tutorials here where we go into more details on the frontal bone.

The other bone that we’re going to be highlighting (from this view) entirely, seen now highlighted in green is known as the occipital bone. And the occipital bone is the only cranial bone to articulate with the cervical spine. It is comprised of four parts arranged around this structure known as the foramen magnum. And these parts include the basilar part, two condylar parts which we cannot clearly see here. We need to go under the skull to… or have an inferior lateral view of the skull in order to see the condylar parts of the occipital bone.

The other one is the squamous part.

Now that we just had a quick overview of the occipital bone, it is time to highlight a set of bones or a pair of bone known as the parietal bones. And the parietal bones are paired bones found on either side of the neurocranium, which is a part of the skull that encloses your brain.

Now, on the internal surface of these bones, we see grooves formed by the middle meningeal arteries due to arterial pressure that causes the bone to, then, recede. And you can see a little bit here on this image, a little bit of these… these areas where the bone is receding, thanks to the arterial pressure. But we can clearly see these when we look at a midsagittal section of the skull. And we have a tutorial which covers that as well here.

Another bone or another set of two bones that we see, highlighted in green, are known as the temporal bones. The temporal bone is a bilateral symmetrical bone which forms part of the lateral walls of the skull. It is comprised of four parts: the squamous part, the tympanic part, the petrous part, and the styloid processes.

Now, we’re going to highlight a set of two structures that are known as the cerebellar fossae. And the cerebellar fossae are located on the internal surface of the occipital bone. And these two depressions house an important structure, the cerebellum.

I’ve been talking throughout this tutorial about the different cranial fossae. And I'm going to start off by highlighting this one here. We have three cranial fossae. And this one that you see, highlighted in green, is known as the anterior cranial fossa, which is a depression located on the frontal bone mainly. And it contains frontal lobes of the brain and is formed by the orbital plates of the frontal bone, the cribriform plate, and part of the lesser wings of the sphenoid bone.

The other one we see a bit more centrally, this is, then, known as the middle cranial fossa. The middle cranial fossa is formed by parts of the parietal bones and the temporal bones. And it houses the temporal lobes of the brain.

The other one is, then, found a bit more posteriorly, to which we, then, will call the posterior cranial fossa, and is an intracranial cavity located in the posterior part of the cranium, and is separated from the middle cranial fossa by the dorsum sellae and the upper edge of the petrous bone.

The foramen magnum lies at its center as you can clearly see here on this image. The posterior cranial fossa contains the brain stem and the cerebellum.

Let’s take a look at the different structures, different foramina that we can see from this view, starting off with this one that you see here, highlighted in green. This is known as the foramen secum. The foramen secum is located between the frontal bone and the ethmoid bone. The emissary vein passes through this foramen from the nasal cavity to the superior sagittal sinus.

The other foramen is known as the jugular foramen. You have two, so jugular foramina. The jugular foramina is located between the petrous part of the temporal bone which you can clearly see here on this image. This is the petrous part of the temporal bone and also the occipital bone as you can clearly see here. Structures that will pass through this foramen include the glossopharyngeal nerve, the vagus nerve, the spinal accessory nerve, the inferior petrosal sinus, the sigmoid sinus, and the posterior meningeal artery will pass through this foramen.

Next foramen that we’re going to be seeing here highlighted in green is also a pair known as the foramen lacerum. And the foramen lacerum, unlike some of the foramina we will be mentioning on this tutorial, does not carry any vessels. It is instead filled with fibrous cartilage. This foramen has the anterior opening for the pterygoid canal and a posterior opening for the carotid canal.

Another pair that we will be highlighting here are known as the foramen ovale, or one is the foramen ovale. The foramen ovale is located on the sphenoid bone, remember from the previous slides. And structures that pass through this foramen include the mandibular nerve, the accessory meningeal artery, the lesser petrosal nerve, and the emissary veins.

The other pair that we’re going to be highlighting now here on the screen is known as the foramen rotundum, or singular, foramen rotundum. This is located at the base of the skull on the sphenoid bone, and the maxillary nerve passes through the foramen rotundum.

The next one we’re going to be highlighting is known as the foramen spinosum. You also have two. The foramen spinosum is located on the sphenoid bone and is located lateral to the foramen ovale. Structures that will pass through this foramen include the meningeal branch of the mandibular nerve, as well as the middle meningeal artery and vein will pass through it as well.

The next foramen—this time not paired and a large one I must say—is known as the foramen magnum. The foramen magnum is surrounded by the occipital bone. It is the largest foramen in the entire cranium. You can clearly see here, and even the name says it all. Magnum meaning “great.”

And the structures passing through this foramen are (there are several because this is quite large) but include the medulla oblongata, the vertebral arteries, and the spinal roots of the spinal accessory nerve will pass through it.

The next structure that we’re going to be highlighting, also a pair, this is known as the internal acoustic meatus. The internal acoustic meatus, singular, is located in the petrous part of the temporal bone. Structures that pass through it include the facial nerve, the vestibulocochlear nerve, and the labyrinthine artery.

Next structures that we’re going to be highlighting are known as canals, specifically the carotid canals. And you have two as you can see here on this image.

Now, a carotid canal contains the internal carotid artery and the internal carotid nerve plexus, which contains sympathetic fibers. The carotid canal is located in the petrous part of the temporal bone.

Moving on to the next structure, here highlighted. This is known as the hypoglossal canal. This canal is a bilateral opening located in the occipital bone lateral to the foramen magnum, and the hypoglossal nerve will pass through this canal.

Another canal that we’re going to be highlighting here is known as the optic canal, which transmits the optic nerve and the ophthalmic artery. From this aspect we see the opening of the optic canal on the sphenoid bone.

The next structure that we’re going to be highlighting here is known as the trigeminal impression. The trigeminal impression is located on the petrous part of the temporal bone, near the carotid canal. It is covered by the trigeminal ganglion.

Next structure that we’re going to be seeing here is known as the carotid sulcus, which is a groove located on the sphenoid bone between the sella turcica and the greater wing of the sphenoid bone. The internal carotid artery runs in this groove as well as the cavernous sinus.

Next structure highlighted here is known as the prechiasmatic groove, and it’s a transversely running groove located on the sphenoid bone, between the optic canals. It lies anterior to the tuberculum sellae.

Next structure that we’re going to be highlighting here or next structures are known as the grooves for the sigmoid sinus. This groove also known as the sigmoid sulcus is located on the inner surface of the mastoid part of the temporal bone. It houses, then, the sigmoid sinus, a dural venous sinus.

Next structure we’re going to be highlighting here is known as the internal occipital crest, which is located in the internal surface of the occipital bone and provides attachment to the falx cerebelli. It runs from the internal occipital protuberance to, then, the foramen magnum.

Next structure that we’re going to be highlighting here, which we mentioned before, this is the internal occipital protuberance, found on the inner surface of the occipital bone. The internal occipital protuberance is, then, located at the center of the cruciform eminence.

Next structures that we’re going to highlight here are known as the arcuate eminences. And these are located on the internal surface of the petrous part of the temporal bone. These bilateral eminences are produced as a result of the underlying semi-circular canal.

Continue your learning

Articles for further reading
Well done!
Create your free account.
Start learning anatomy in less than 60 seconds.