hello everybody and welcome back today we're going to be looking at the viscerocranium or the facial bones and I think the best place probably to start is by looking at the maxilla in some detail the maxilla interacts with all the other facial bones and we'll see how these bones combine to form the different facial structures now the maxilla is actually two separate bones that meet at the midline at the inter maxillary suture and the maxilla we can think of is having a body in four separate processes superiorly we have frontal processes laterally zygomatic processes and inferiorly the alviola process and then the process we often forget about the Palatine process that extends posteriorly which makes up the majority of the hard pallets so let's have a look at our CT scan and try and figure out where the body is and then look at those processes to start so we head over we'll start with the axial slice and we can see that on either side of the nasal cavity here we've got two large paranasal sinuses these are what's known as the maxillary sinuses now the body of the maxilla hows the maxillary sinuses so we can see the anterior wall of the body here the medial wall makes up the lateral walls of the nasal cavity the posterior wall makes up this anterior surface or anterior boundary of the terop Palatine fosser and our posterior lateral wall of the body here faces out towards this space which we call the infratemporal fossa it's called the infratemporal fossa because it lies below the temporal loes if I scroll up super we see we enter the middle cranial fosser that we looked at in our neurocranium torque and that's where the temporal lobe lies so as we scroll down inferiorly we'll reach this infratemporal foser this is not intracranial it lies underneath the cranium you can see that on our coronal scan the medial walls of the body make up the lateral walls of the nasal cavity and if we scroll posteriorly we can see that behind the maxilla here is the infratemporal fosa you can see it beautifully demonstrated here here's where the temperal lobe lies within the middle cranial fosser now as we head out anteriorly again we can see that the roof of the body of the maxilla bone or the roof of the maxillary sinuses makes up the floor of the orbit here and we can scroll more and more anteriorly you can see the floor of the orbit and as we head out anteriorly to the infraorbital margin the mailla makes up at least a half of that infraorbital margin that medial half now you may notice as we've been scrolling through here there's a canal that runs along the floor of the orbit here this is the pathway for the infraorbital nerve now the infraorbital nerve is actually a branch of the maxillary division of the trigeminal nerve now you remember from the neurocranium talk that the maxillary division passes through the fan rundum so let's maybe have a look at the pathway of the infraorbital nerve if we scroll posteriorly we can find the foran rundum we know that the Fram r tandum heads anterior to posterior like someone looking through binoculars and we can see it nicely demonstrated here can find that on our axial slice as we scroll up the framan randum is here on either side this is actually a beautiful slice I'm going to make sure to include this in the question bank that I've linked below now the maxillary division of the trial nerve passes through the framan rundum and one of its branches is going to head into the inferior orbital fure now when that Branch passes through the inferior orbital fure it becomes the infraorbital nerve so let's go to our coronal slice and scroll forward until we see the inferior orbital fissure here this is where the nerve becomes the infraorbital nerve as we scroll forward here's the inferior orbital Fisher heading out laterally we will see a Groove forming here this groove is known as the infraorbital Groove as we had more and more anteriorly that Groove becomes a canal which is the infraorbital canal and that Canal then heads out to the front of the face the anterior surface of the face and exits as the infraorbital framan you can see that as well on our 3D model the groove then extending into the bone into the floor of the orbit becoming the infraorbital canal and then heading out anteriorly as the infraorbital forment here you can see that on our axial scan as well as we head out through the inferior orbital fissure we will see the groove being formed here then becoming a canal and that Canal heading out anteriorly as the infraorbital forment so we've looked at the body now let's try and find the processes if we go on our axial slice cuz we're here and we head up superiorly we'll be able to find the frontal process of the maxillary bone so we can see we're at the floor of the orbit here as we head up more superiorly this bit of bone here is the frontal process of the maxillary bone anterior to that are our nasal bones that we looked at previously we can see on the sagittal slice here the nasal bones that extend to the Nason and superiorly the gabella lying above the nasal bones we can look on our coronal slice and we will remember here that the Nason is where that frontal bone meets the nasal bones at the midline the nasal bones are separated by the internasal suture and this point here is what's known as the Nason as we head out posteriorly here are the frontal processes of the maxilla now as we head more and more posteriorly the next bone that we're going to encounter is the lacal bone and we're going to look at that later when we look at the nasal lacal duct so that's the frontal process let's stay on the coronal plane and look for the zymatic process we know that the zygoma forms a zygomatic Arch anteriorly it's a zygomatic process of the maxilla that joins with the zygoma and posteriorly it's the zygomatic process of the temporal bone that we looked at previously so here we can see the zygomatic process joining with the zygoma that zygoma is going to form the zygomatic Arch here and as we head more and more posteriorly we can see the zygomatic process of the temporal bone coming off that squamous section of the temporal bone that we looked at earlier that's forming the zygomatic Arch I'll show you that on our axial slice here's the zygomatic Arch there's not much to the zygoma so we may as well talk about it here the zygoma has an anterior surface it's got a posterior surface that faces the infratemporal fucer that we looked at and if we scroll up superiorly the zygoma also has an orbital surface here it makes up the majority of that anterior lateral part of the orbit I'm going to show you that on our 3D model so there's three separate surfaces here and we've got three processes that extend out to the zygoma the zygomatic process of the frontal bone the zygomatic process of the maxillary bone and the zygomatic process of the temporal bone let's now look for the alola process proces our third process of our maxilla we head down inferiorly and we're looking at the bottom of our maxillary sinuses here we can see we start seeing the upper teeth here in the upper jaw these bony processes that house the upper teeth is what's known as the alola process remember these are actually two separate bones and the intermaxillary suture is at the midline here there should be eight teeth on either side let's have a look on our coronal scan we can see why they are processes because the the maxilla extends down like this and look how the roots of these teeth come into very close contact with the maxillary sinus you might notice that the maxillary sinus extends out here this is what's known as the alviola recess of the maxillary sinus we also have zymatic recesses of the maxer sinus as we head out towards the zygoma our last process that we're going to look at is the Palatine process that extends out posteriorly you can see the Palatine process lying across here lying horizontally on alaron scan here it's best looked at on our sagittal scan where you can see the Palatine process extending out posteriorly here we're at the midline and you can see a fmen running behind the incises this is the incisive fmen here actually while we're here you can see a Remnant here which we didn't look at when we looked at our neurocranium talk and this is our fan seeum sometimes you can have a vessel a patent fan running through here and a vessel extending from the nasal cavity up into the cranium that's an anatomical variant while we're here so we can see the incisive framan this is where the nasopalatine nerve runs through and the greater Palatine vessels can pass through here now the Palatine process extends posteriorly it makes up about 2/3 of the hard pallet before becoming the Palatine bone which we're going to look at later if we have a look at our axial slice we can scroll down to the Palatine process or in this case scroll up to the Palatine process and we can see we're just catching it in cross-section here anteriorly we have this anterior nasal spine it lies just below the opening in the nose here you can actually feel that here there's a bony projection extending out here this is the anterior nasal spine there's a posterior nasal spine when we look at the Palatine bone which is here the posterior nasal spine the Palatine bone or the Palatine process of the maxilla is separated along its midline by the median Palatine suture the Palatine process is separated from the Palatine bone by the transverse Palatine suture now while we're here we mentioned this anterior nasal spine and on our sagittal view we can see there's an opening here this opening is what's known as a perform aperture now the lateral walls of the perform aperture and the inferior border of the perform aperture is made up by the maxilla bone and that Superior margin is made up by the nasal bones we can look at it here on our coronal slice as we head out anteriorly here are our nasal bones making up the superior border and then the maxilla making up the lateral and inferior borders of this opening here it's called the perform aperture perform meaning pearshaped in Latin so that opening here anteriorly is called the perform aperture if we head out posteriorly and we see the posterior opening into the naso faring here more and more posterior these posterior openings are what's known as COA we can see that here on our sagittal the COA here and perform aperture here now you may have noticed when we were going through our coronal scan that you've got these spiral-shaped passages within the nasal cavity here now we're going to look at the nasal cavity in more detail when we look at the paranasal sinuses but as we were scrolling through here to look at the perform aperture you may have noticed that actually with in these spiral shaped structures there's a very thin bone it's quite difficult to see here that's actually a separate bone known as the inferior nasal conquer the inferior nasal conquer separates the inferior nasal meatus from the middle nasal meatus now again we're going to go through this anatomy in some detail later on but this just to let you know is a separate bone conka in Latin means shell-shaped if someone's blowing a conch to make a horn sound that shell is wrapped over on itself and you can see why this is called a conquer there's a middle and superial nasal conquer and that is formed by the ethmoid bone we're going to look at that later we can go over to our axial slice and see that inferior nasal conquer here separating the inferior nasal meatus from the middle nasal meatus now different structures drain into each one of the Mii and here we can see that our auxilary sinus actually drains into the middle nasal meatus here this is our middle nasal meatus this is the middle nasal turbonet the maxillary sinus drains through this complex known as the osteomeatal complex this opening here is called the maxillary osteum and then we extend through the infundibulum into a structure known as a Hiatus semi lunaris and this hook of tissue here is what's known as the uninet process uninet meaning hook we've seen the uninet process in the pancreas for example this complex again we're going to look at more when we look at our paranasal sinuses so we've looked now at the maxillary bone now let's have a look at some of the other facial bones that interact with the maxillary bone we last looked at the Palatine process of the maxillary bone extending out posteriorly and you may have noticed that there's a thin sheet of bone lying above the Palatine process that thin sheet of bone is what's known as the voma the voma is an unpaired bone that separates the nasal cavity it bifes a nasal cavity you can see it extends from the body of the sphenoid bone you might remember this from our previous talk here's a hypothesi or fosa we've got the clus we've got the plum sphenoid or the sphenoidal body or sphenoidal Yol and then inferiorly we've got the voma extending down towards the Palatine process the voma attaches to the sphenoid Bone at the inferior sphenoid Rostrum if we go back to our coronal slice and we head posteriorly and find that sphenoid sinus here we can see the Rostrum being formed here and the voma extends to that Rostrum and has these two little wings called the AAR of the voma that attach to that inferior surface of the body of the sphenoid the VMA bone contributes to the Bony nasal septum when we look at our nasal septum here on the axial slice you can see some of the nasal septum is bony and then anteriorly we've got the cartilaginous nasal septum that allows the nose to move externally with without actually any bones being broken here posteriorly it's a bony nasal septum the voma makes up the majority of the posterior part of the Bony nasal septum and the inferior part superiorly we've got the perpendicular plate of the ethmoid bone if we go back to our coronal and then we head out anteriorly we'll see the ethmoid air sinuses coming into view and you'll see that there's this perpendicular bone that runs down the middle of the ethmoid bone I'll show you what that looks like on the 3D model as well that perpendicular plate then joins with the voma forming the Bony nasal septum here we can see the crystal that is the superior surface of our ethmoid bone and it's quite difficult to see here but this middle septum here is what's known as the perpendicular plate we can see the ethmoid bone makes up the roof of our nasal cavities as well as making up the lateral borders of the ethmoid air sinuses and the nasal cavities this lateral border here is what's known as the lamina paparia a very thin bone that makes up the medial walls of the orbit we again we're also going to look at the ethmoid and how it drains into the nasal cavities in more detail when we look at paranasal sinuses the last part of that bony nasal septum is this process extending up from the Palatine process or from the maxilla and that's what's known as the maxillary Crest all of those three structures make up the Bony nasal septum now when we were looking at the osteomeatal complex we saw that the maxillary sinuses drain into the middle nasal meatus and you may have noticed that while we were scrolling through there was another pathway that extended down here this is a different pathway we can see it coming from the orbit here and as we scroll anteriorly it's extending down into the inferior nasal meatus it's often better seen on our sagittal slice as we head out laterally we can see that from the orbit down into the inferior nasal meatus is this pathway here that's what's known as a nasolacrimal canal now I mentioned the lacrimal bone when we were looking at the frontal process of the maxillary bone said the frontal process of the maxillary bone extended up and was separated by the nasal bones and there's a Crest that's formed that's known as the anterior lacal Crest that Crest is on the frontal process of the maxillary bone behind that Crest is what's known as the lacal foser that houses the lacrimal Sac superiorly that lacrimal fosser then marks the point of where the lacrimal bone is formed the lacrimal bone is a very small bone it makes up some of the medial portion of the orbit if we scroll a little bit more we can see that there's a small little Crest here known as the posterior lacrimal Crest that marks the margin for when the lacrimal bone is separated into its orbital surface and its lacrimal surface if we follow the lacrimal Sac now inferiorly and head down further and further we've got a lacrimal hook here that extends and joins the maxilla we've now created a canal that houses the nasolacrimal duct that Canal the nasolacrimal Canal extends down into the inferior nasal meatus there's actually a valve here known as the valve of hassner that prevents fluid from flowing up the nasol lacrimal Canal so the lacrimal bone is just a small bone it interacts with the frontal process of the maxillary bone at the lacrone maxillary suture posterior to the lacal bone is the ethmoid bone that lamina paparia that extends and makes up the rest of the medial border of the orbit and that's about it for the superior and anterior facial bones now let's head inferiorly and look at the Palatine bone and the sphenoid bone and how they create some unique facial structures let's go to our sagittal slice go back to the midline and let's find the Palatine process we said that the Palatine process of the maxilla then joins to the Palatine bone and then we've got a transverse Palatine suture separating that Palatine process from the Palatine bone now the Palatine bone has a horizontal part and they vert iCal part the horizontal part extending out posteriorly and horizontally and the vertical part of the Palatine bone extends from the lateral borders of the Palatine bone and extends superiorly towards the teroid processes of the sphenoid bone so we got the sphenoid bone superiorly sending down the teroid processes we've got the Palatine bone inferiorly sending up its vertical part of the Palatine bone so let's head out laterally and hopefully they will see that there are these structures heading up we've got teroid processes and we've got the p bone extending superly now it's difficult on this view to see exactly what's Palatine bone and what's phid bone so we're going to go over to our axial slice here what I find easiest is to find the sphenoid sinus find the sphenoid bone and get your orientation we've got the clus posteriorly here the sphenoid here the body of the sphenoid and as we head out inferiorly we will see these processes coming down these processes are the teroid processes of the sphenoid bone the lateral process form as an attachment point for some of the muscles of mastication and we're going to look at the muscles of mastication in great detail a whole video looking at where they attach and what movements they have on the face so that's the lateral teroid plate the medial teroid plate as we head out infer you see actually hooks round underneath the lateral teroid plate you see how it's hooking around like that we'll see it better on our coronal slice as we head out posteriorly will come into contact with those teroid plates we've got a lateral teroid plate and a medial teroid plate can see it on both sides look how that medial teroid plate actually hooks around and that can vary from Patient to Patient so we've seen where the teroid processes are how does that relate to the Palatine bone again let's head up superiorly and we've looked we've mentioned multiple times this terop Palatine fossa now our next video is going to look at the terago Palatine fossa in some detail and getting an appreciation for these structures now is going to serve well as we go into that video but as we head up superiorly in the terop Palatine foser we're going to see an opening here that's known as the sphenopalatine framan which connects the terago Palatine foser to the nasal cavity slightly Superior to that sphenopalatine framan we're going to see a canal that's extending from the cortic canal or more specifically from the fan lerum here heading out and connecting the terop Palatine fosser to the cortic canal to the fan lerum this is what's known as the vidiian canal or the teroid canal and the vidian artery as well as nerves pass through this canal we can head out more superiorly we should be able to see the foran randum that's Superior and lateral to the Vian Canal if you find the fan randam and head down inferiorly that marks where the terago Palatine foress starts let's find the vidian canal again and we know that medial to the vidiian canal we also have a passageway we've seen the sphenopalatine forment we've seen the Vian Canal medial to that is the petto vaginal Canal now the p vaginal Canal can sometimes be biffed like this have two separate canals or it can be a single Canal heading down into the naso faring here and that's why this is called the fenal Canal because it connects the terago Palatine fosser to the fing here and it's the fenal nerve that runs through the fenal Canal now the reason I'm showing you these structures is to show you how to find the superior aspect of the terago Palatine fosser you can see on our sagittal section here we've cut the terago Palatine fosser and as we head down inferiorly we can see that two separate fans form known as the greater and lesser Palatine frina the greater Palatine framen is normally more anterior and often more lateral and the Lesser is poster those are the two exit points of the terago Palatine fosser we can see them here and as we head out actually to our sagittal slice see how you can see the Lesser Palatine framan here laterally and then the greater Palatine framan heading out into the Palatine bone here so the Palatine bone makes up this medial wall of the Tero Palatine fossil let's head up this medial wall here is is the Palatine bone it's the vertical portion of the Palatine bone that vertical portion terminates at that speno Palatine frame in here so you can see how closely the vertical portion of the Palatine bone interacts with the teroid process of the sphenoid bone heading down inferiorly this vertical portion in some cases can actually extend up and make up a very small portion of the orbit here at the posterior medial surface of the orbit but that's difficult to see on the scan so let's move on to our last bone and this bone is a little bit controversial because some people don't include it in the viscero cranium it's not technically attached to the skull itself and that's the mandible now I've used this very detailed scan here and this doesn't actually include the mandible so I'm going to head over to another scan and we're going to look at the mandible here while we're here we may as well look at it so let me change over to that scan now I've actually got a C scan of the cervical spine we're going to get the mandible in nicely here let's get our orientation go to our sagittal slice we can see the Palatine process here we can see the incisive forment here is the alviola process of the maxillary bone our nasal bones were at the midline here you may notice then that below the maxilla below the Apple teeth we have this other bone known as the mandible that's what we're going to look at today I'm extending out laterally here is the mandible wrapping all the way around we know the mandible it's the lower jaw let's head on to our axial slice and go down to the mandible the mandible houses the lower teeth and we can separate the mandible also into multiple different parts the body of the mandible is this anterior part here the body can be separated into a bony part and an alola part the alola part is what houses the teeth the Bony part is below the teeth here this bony part is also known as the base of the body of the mandible now as we head out posteriorly we're going to reach an angle here that's better seen on our sagittal slice we go to this angle this angle posteriorly is what's known as the angle of the mandible the angle of the mandible marks where the body then becomes the mandibular Ramis the Ramis is this vertical portion of the mandible here on our coronal scans you can see the Ramis heading from inferior to Superior making up these two bony RI the r is then extends up superiorly into two different processes a cond process that has a neck and a head and articulates with our temporal bone remember we have that shallow condol fosser of the temporal bone lying on the inferior surface of the temporal bone and then we have this Notch forming known as the mandibular Notch that extends out anteriorly to a process that's known as the coronoid process and it's the coronoid process that's an attachment site for the temporalis muscle again we're going to look at this in some detail when we look at muscles of mastication now you may notice that while we scroll through the mandible there are a couple of param here we can see anterior there's a small feramin on either side of the body of the mandible this is what's known as the mental foramin and you'll be able to see that when you look at the 3D model now we've seen three separate framer coming out anteriorly to the skull we've seen the supraorbital framen the infraorbital framen and the mental framen and those nerves are from the three separate divisions of the trigeminal nerve the op thermic division maxillary Division and mandibular Division if we head out posteriorly on this mandible you can see on the interior surface or the medial surface of the mandible here on the Ramis of the mandible we have these two canals being formed here that's the mandibular Canal where the inferior alviola nerve travels in that mandibular Canal it's also a branch of the mandibular division of the trigeminal nerve so that interior opening that's a mandibular forment and that extends into the mandibular Canal here so that's about all I want to cover for the mandible now the mandible obviously has many different movements it's got many different muscle attachment sites we can see that it also the RIS of the mandible here separates the superficial and deep limbs of the parotic gland it's a complicated region we're going to look at this closely in multiple different talks muscles of mastication muscles of facial expression we're going to look at the Deep neck spaces and these structures become incredibly important I hope that this video has given you a good understanding of how the viscerocranium how the facial bones connect with one another to form these complex face structures here now the best way again and I'm always going to say this to learn these structures is to go through scans yourself and try and identify each one of these structures I've linked below a bank of questions every time I do a video I'm going to be adding to that bank of questions we've had multiple people already go through it and really enjoy the questions I'm trying to make the level of those questions that of the FC part one exams or your Radiology part one Anatomy exams people often fall short in those exams because they're stressing about the physics and don't realize how complicated some of this Anatomy can get so I've included quite complex questions in that question bank that you can go and check out in the description below I can't wait to get to our next video because I feel like I've mentioned the Tero Palatine fosser many times in both of these talks we're going to look at it in detail it's a great structure to know because once you know that fosser you can kind of work your way out in the scan and figure out the surrounding Anatomy so until that video I'll see you all there goodbye everybody