Skull bones, sutures and landmarks

okay let's talk about bones sutures and landmarks of the skull and answer the what questions what are the bones sutures and landmarks of the skull and what are the cranial fossae hello everyone my name is dr. Morton and I'm the noted anatomist okay so the skull is an old norse word that means scaly or a bald head so here we have a bald head and we have a skull in yeah they both look bald and so the skull to cover it today we're gonna do the following we're gonna talk about the bones and the sutures and the landmarks in the following way we're gonna do bone sutures and landmarks on the anterior part of the skull then lateral part of the skull then posterior then soupier then take the calvarium off and look at the cranial fossae with the calvarium removed and then look at the skull base of the inferior view now a note before we get started is that the perspective of this tutorial is towards health professional students and so it's to the clinical relevance of each of these are the major structures so if this is for like an advanced anatomy class worth every single for aminah every single suture i'm not be covering all of them but i'm still covering a lot of them so sit down get comfortable get yourself some hot chocolate and let's get started so we're gonna first do the anterior view of the skull and talk about first the bones well the frontal bone is located here it's the part of the forehead because frontal means is Latin for forehead above the eyebrows and so right there is where the frontal bone is located now the parietal bones are located on the lateral side of the skull and they're ones are going to be talking about in another view the sphenoid bone you can find in the lateral part of the skull behind the orbit and also within the orbit but superficially the sphenoid bone is felt right behind the orbit and it's actually what most people say the massage their temples that's actually the sphenoid bone the temporal bone is located above the ears right about there and then the zygomatic bone is the bone that's located right along the cheeks so the maxilla is this bone here in purple and it is Latin for jaw and it's the part that's of the upper jaw all the way up to the side of the nose now the nasal bone is located here because nasal means nose now oh is that Wonder Woman nope it's Diana Prince and you can tell because she's wearing glasses and glasses sit right on the bridge of the nose on the nasal bones now the mandible is the lower jaw here and we'll talk about that in a few minutes let's talk about now sutures the only suture we really see the mean when we see here is the coronal suture that goes up and down we'll talk about that suture later on let's talk about the landmarks in the front of the skull well the frontal sinus is located within the frontal bone there's a frontal bone and the frontal sinus are these hollow caves within the bone itself and so in this x-ray we can see the frontal sinus and let's outline it there there is a frontal sinus that it's used for it makes mucous because it's mucosal lined inside but it's a cave and it helps with the resonance of sound and here's a lateral x-ray and that yellow arrow showing the frontal sinus now the supraorbital margin gets its name because supra means above and orbital means above the orbit there's that margin above it's the part that's right below your eyebrow super orbital margin now in the supraorbital margin there is a supraorbital notch now sometimes it's a notch and sometimes it's a foramen so super orbital notch or foramen and it traverses the following the super orbital artery on way to the front of the scalp and the super orbital nerve which is also giving innervation to the front of the scalp so we take this section now we're gonna take and do this different view and there's what it's a structure called the supraorbital fissure and then there is an infraorbital fissure and then there is the optic canal so let's do that again so there's optic canal superior orbital fissure inferior orbital fissure and we're going to now superimpose and blow that up and let's talk about what's inside each of these so the optic canal superior orbital fissure inferior orbital fissure now the optic canal contains cranial nerve 2 or the optic nerve that goes from the retinas for vision it also contains the ophthalmic artery that supplies the or and derived arises from the internal carotid artery there's our superior orbital fissure that contains the superior ophthalmic vein and then the following for cranial nerves three four five and six now I did it in that order because it's easy to remember in numerical order three four five six specifically v1 of trigeminal v2 and v3 do not go through here now this is an oversimplification because super orbital fissure actually looks like this where there's cranial nerve three and upper and lower division creating them therefore which is above three cranial nerve five which has a lacrimal frontal a nasal ciliary branch v1 and then cranial nerve six down at the bottom but because if we take a look at the size of the superior orbital fissure is just a couple of inches so unless you go into eye surgery this has been my experience is sufficient to know super orbital fissure that superior thalmic vein three for v1 and six now the inferior orbital fissure is the inferior ophthalmic vein cranial nerve V dash to the infraorbital nerve and then our infraorbital artery and vein so there are the three major openings in the orbit now the nasolacrimal duct is located right there let's take another view right there and that nasolacrimal duct is does the following here's the orbit there's our lacrimal gland that when innervate it produces tears that wash the eye and go down through this nasolacrimal duct into the nasal cavity hence why when you cry you actually usually get a runny nose that is the nasolacrimal duct going between the medial corner of the eye all the way down to the nasal cavity all right so now we're going to look in more of a going down looking up there is our infraorbital foramen right there and that infraorbital foramen traverses the inferior orbital nerve there and our inferior orbital artery there as well supplying the lower eyelid lateral nose upper lip there is our inferior nasal Concha and our middle nasal conchae and there is our nasal septum in the nasal cavity so the mental foramen is located right there and it traverses the mental nerve a branch of v3 that supplies the chin in the lower lip and then there is our mental symphysis and there's a little notch in the mental symphysis which is usually what gives that little dimpled chin as you see in John Travolta and so now we'd look at the piece Cullen the on your right in this dermatome picture on the left there's the superior orbital frame and it gives rise to a branch of v1 that's where you test the v1 dermatome and the infraorbital framing gives rise to the infraorbital nerve which is where you test the v2 dermatome and the mental Freeman gives rise to the mental nerve is where you test the v3 so above and below the eyes on the orbit and then in the lower lip the way you test the trigeminal dermatome Fields now let's do the lateral view of the skull and start with bones and so here's our frontal bone forming the forehead and then there's our parietal bone and the word parietal means is Latin for wall because it forms the wall of the cranial vault and where do you see this term parietal well the parietal pleura which is the mesothelial lining of the wall of the lungs or the parietal pericardium which is the mesothelial lining of the wall of the heart so whenever you see the word pride alike parietal peritoneum parietal bone it means the wall sphenoid bone located here it forms right behind the orbit and then the temporal bone which is located right there in this salmon color and temporal means time because if you were to add the ear on to that that's where grey hair usually comes and so what happens is when you take a look at the bone underneath where usually gray is why it's called the temporal bone the zygomatic bone is located here with that weird zygomatic means to yolk or bring together I'll talk about why that's the case in a minute and then here's our maxilla which is the bone of the upper jaw and then the nasal bone which is at the bridge of the nose and then there's our lacrimal bone which is right inside the medial wall of the orbit it gets its name because it's part of the nasolacrimal duct and lacrimation means to tear that's were you're draining the tears and then there is our mandible now the term mandible is latin to chew and it gets that name because the mandible is what is responsible for this mastication movement of the jaw and then there's our occipital bone and the occipital bone is Latin for the back of the skull because occiput is the back of the skull now let's talk about the sutures from a lateral view so the coronal suture is first and it's the coronal sutures suture is between the parietal and frontal bones right there there's our coronal suture and it gets its name because the word coronal is Latin for a crown of Garland and you can see where that crown of Garland is located and you look at the suture off that's why it's called the coronal suture because it is like a courses like a crown of Garland now the squamous suture are squamosal suture is between parietal and temporal bones right there on the squamous part of the temporal bone and then the lambdoid suture is between parietal and occipital bones right there is our lambdoid suture now the Terry on is a very significant little suture between parietal frontal sphenoid and temporal bones and it means winged because it forms on the lateral part of the greater wing of that sphenoid bone located right there now clinically it's important because if injured for example like us hitting the head against the side of of the the car window when you're in a car accident or in Canada like a slap shot of a puck right onto the side of the temple if you're not wearing a helmet because what happens is deep to the terry on is an important artery so here in the info temporal fossa is the external carotid artery that gives rise to the maxillary artery that gives rise to an artery called the middle meningeal artery coursing through that frame and spinosum and then that middle meningeal artery supplies a good chunk of the dura mater and right there is where the tirion is located in if you hit the Terry on deep to the bone is a is this little artery called the middle meningeal artery because of how thin the terian area of the bone is it could rupture and cause bleeding separating the dura from the skull forming an epi outside the dura mater collection of blood epidural hematoma all right now let's talk about landmarks from a lateral view there is the external outside occipital protuberance there and then there is the petrous part of the temporal bone now this part that arrows showing where the petrous part of the temporal bone is but it's deep to this area it's like basically running your hand over the ground but what you're meaning is stuff underneath the ground because the Horn petrus means Rock like petrified and so in this lateral view of the skull whenever you see bright white it means it's very dense and there is that petrous part of the temporal bone it's housing the the internal ear like your cochlea and semicircular canals now the mastoid process that the temporal bone is located right there and the word mastoid means is Latin for breast shape think mastectomy and there is that mastoid process of the temporal bone and outline there is our sternal cuido mastoid muscle and the mastoid process is its insertion in this lateral V x-ray there is that mastoid process but within the mastoid process are these mastoid air cells which is like sponge-like formation of bone that communicates with our middle ear now the external acoustic meatus is here and the word external means outside niku stick means to hear anomie ADIS mean some type of a passageway and so that external acoustic meatus is right there they're opening to the outside of the ear where people used to put q-tips and I was gonna make a whole thing about your just be careful don't poke your eardrum with it because when you look inside the external acoustic meatus right there deep inside is the tympanic membrane also known as your eardrum now the zygomatic arch is formed by the zygomatic bone in its Union - the zygomatic process of the temporal bone and together they yoke together to make these maduk arch hence the word zygote if you think of that from embryology where a zygote is the union of a sperm in an egg Saigo Maddock is arch is the union between the zygomatic bone in this temporal bone and it's located right there and so that zygomatic arch all along here forms as an attachment for the masseter muscle which courses down to the mandible as well as deep to the zygomatic arch this temporalis muscle goes deep and attaches to the coronoid process of the mandible the nasolacrimal duct from a lateral view is located right there to drain tears into the nasal cavity and then the ramus of the mandible that word ramus means a branch it's all along there and that's where the masseter muscle attaches all along the ramus of the mandible and then the coronoid process located right there is where the temporalis muscle inserts to allow to elevator both in the masseter and temporalis to masticate and then there's our mandibular condyle right there which allows for this type of chewing motion and then there is our mandibular notch okay now the skull from a posterior view and we'll start with bones so the parietal bones are located right there on the side of the skull then the occipital bone is the back of the skull and then the temporal bone which is the side of the skull and now let's talk about sutures so the lambdoid suture is located between parietal and occipital bones and it's located here and that lambdoid suture gets its name because the word lambda is a Greek alpha like that symbol Lamba is the Greek alphabet that looks like this that upside-down V which looks just like that lambdoid suture the sagittal suture is between adjacent parietal bones right there she so let's now talk about landmarks so the external occipital protuberance is there and coming on and protuberance means a lump or swelling because that's what it is now the superior nuchal line is located all along there with the word nuchal means the nape of the and if you have a soup here nuchal line you must have an inferior nuchal line which is located right there in both superior and inferior nuchal lines are for muscle attachment now the occipital condyles are their occipital for occipital bone and condyles which means a knuckle or Knob and these occipital condyles located right there articulate with the c1 vertebra also known as the atlas that allows for the yes no yes up and down motion the mastoid process is located there from a posterior view and now let's talk about the skull from a superior view and start with bones the frontal bone forming the forehead in blue the parietal bones in green forming the major wall of the cranium and the occipital bone in purple forming the back and so for sutures first suture is a coronal suture between frontal and parietal bones located right there there's our coronal suture in the coronal plane then the sagittal suture is located between adjacent parietal bones right there she and it's called the sagittal suture because if you remember in introductory Anatomy that plane that divides a structure until equal left and right portions is a sagittal plane or a sagittal section hence why that is the sagittal suture because it courses in that sagittal plane all right now the lambdoid suture is between parietal bones and occipital bone right there and you can see from the superior view making that lambda symbol okay here's a lateral view of the skull we're gonna do this Shing and separate this calvarium and take the calvarium and look inside at the cranial fossa or the base of the skull internally and that's the cranial fossa and so we're gonna talk about the bones first so the frontal bone in blue is the very front of the skull and then in green is the ethmoid bone and the term ethmoid is Greek for a sieve or a strainer like to make spaghetti because take a look you make spaghetti oh that you can throw must imagine making using the ethmoid bone bone ethmoid bone to drain spaghetti now the sphenoid bone is located here I said bones should just say bone there's our sphenoid bone and it means is Latin for wedge because this bone is wedged right in the middle of the skull where so many other bones articulate with it it also looks like a butterfly and then Perata bones are in the lateral part of the skull and then the temporal bones form a big portion of the middle cranial fossa and that what I've shown there a good chunk of that is the petrous part of the temporal bone the squamous parts on the outside and then the occipital bone which I have bones it should say bone I mean I get my plurals and singulars mixed up sorry and I've made this video a thousand times already it's supposed to be a post on a Friday that's Saturday I'm going with it alright so now let's talk about the landmarks and so the orbital plate is this part of the anterior cranial fossa and the frontal bone right there and if you were to crack through that you get the orbit also the extraocular muscle muscles in the globe now the groove for the superior sagittal sinus is right there the superior sagittal sinus is a dural venous sinus that anteriorly drains down or or it could be blood of course in either direction but the groove is for the part of the superior sagittal sinus just the anterior part then there's the cribriform foramina now that's the cribriform foramina the term cribriform is Latin for sieve-like or riddled with small holes and so it is because in this lateral wall of the nasal cavity these olfactory nerves coming from that superior nasal Concha here ascend up and then they go through all these little holes that cribriform foramina and the olfactory nerves synapse in the olfactory bulb which then goes out to the brain now the crista galli is located right there and crista galli means is Latin for the crest of the rooster and so how does that look well let's take a look at another view right like that there is that crista galli so that it looks like the crest of a rooster now why does the crista Khali do it serves as an attachment for the falx cerebri here on orange which is this longitudinal structure of dura mater that separates our cerebral hemispheres and then right there attaches and anchors to the crista galli all right now let's zoom in and show the lesser wing of the sphenoid bone there in yellow which is on the anterior cranial fossa and you can see those client into your culinary two processes lesser wing now the greater wings are in the middle cranial fossa which on either side of the body of the sphenoid where the sella turcica is located all right so now let's go into this area of the cell at rest so we zoom in and so there's something called the anterior claw noid processes right there that serve as an attachment for the tentorium cerebelli and then there's the posterior claw noid processes right there now what happens is these two anterior and to posterior clean wide processes anatomist looked at that and they said what should we call these and well the term Clannad means is Latin for bed because it kind of looks like a four-poster bed one two three four and what's in the middle sleeping our pituitary gland and so the hypothesis AUSA there houses the pituitary because hypo means below Fasil means outgrowth and that's the pituitary gland it's an outgrowth of the hypothalamus all right and so here is a sagittal section of the skull and there is a hypothesis lhasa because it's what houses our pituitary gland now here we have the dorsum Celie where dorsal means behind and Celie means saddle or the back of the saddle and so there we've got in the sagittal section there's the hypophyseal fossa and there's the dorsum cellie with a yellow arrow now the sella turcica then is a combination of things it is the hypothesis lhasa plus or - posterior claw noid process these plus the dorsum sally that's what makes the sella turcica and sella turcica translation is a Turkish saddle because that's what it looks like now in this x-ray we're gonna zoom in there is the hypophyseal fossa and there is the dorsum Celie and there we have the sella turcica now off we'll just call that whole thing the sella turcica okay now if you find it below the sella turcica if you were to punch a hole through that saddle you're in the sphenoid sinus if you find the sphenoid sinus you're like oh there's the maxillary sinus if you find the maxillary sinus oh there's the hard palate hey and if you find the hard palate there the maxillary teeth what happens is I look for happy faces and x-rays if I find one thing like the sella turcica it introduces me to other things in the skull alright now this is a superior posterior view of the base of the skull we're gonna go over optic canal superior orbital fissure there's our optic canal coursing into the orbit for cranium left to an ophthalmic artery and there's the super orbital fissure also going into the orbit and I've only shown one on either side but their bilateral super orbital fissure is for the super op thalmic vein cranial nerves three for v1 and six now let's do the same thing from this view there's our optic canals and there's our superior orbital fissure now the frame in rotunda is right there in rotunda means Brown so it literally means the round hole from this view you can see that round hole and is from that view the round hole now that is in contrast to this foramen ovale you know Valley is Latin for oval for this oval looking foramen right there now the frame in O Valley is for the v3 nerve so there's our trigeminal nerve cranial ER five and there's v3 going through the foramen ovale on the bottom of the skull that's where v3 goes into the m4 temporal fossa and supplies the mandible tongue and lower part of the oral cavity the framin spine owesome is there and that framin spinosum gives rise to the middle meningeal artery that supplies the dura mater and that's where the tear Aeons located where it could get fractured all right now the framin lacerum is there now the frame in lacerum is actually filled with cartilage so it's really kind of an it's it's a good landmark to show okay now the carotid canal however is in a tunnel right there there's our crowded canal and so here in this lateral view of the skull and you see brain cerebellum and our there's our internal carotid artery there is the carotid canal in what we're seeing is that opening the top of the canal now the lesser and greater petrosal high a dime so here we're doing in there is a frame '''l valley in the frame and lacerum as landmarks and so there's the lesser petrosal hiatus and the greater petrosal hiatus now the lesser petrosal hiatus gives rise to the lesser petrosal nerve that goes through the frame in ovalle with v3 but the lesser petrosal nerve after synapse and in the otic ganglion innervate sour parotid gland now the greater petrosal hiatus which a hiatus isn't opening gives rise to the greater petrosal nerve that traverses kind of through that frame and lacerum synapses in the tear go palatine ganglion and then innervates the lacrimal and nasal palatal glands to make your eyes water and mucus to give you moist mucous membranes there's our greater and lesser petrosal hiatus now the internal acoustic meatus is right there internal means inside an acoustic means to hear and so there we've got this coronal section again there's our internal acoustic meatus with cranial nerve seven and eight going into our internal ear for the cochlea and semicircular canals for cranial nerve eight now there is our external acoustic meatus which is the external year now I'm showing this because the external and internal acoustic meatus is not like a train tunnel from one in and out the other because the middle ear is what separates this well the internal year as well but basically that middle ear so goes external ear middle ear with the malleus incus and stapes and internal ear the cochlea and semicircular canals now the groove or the sigmoid sinus is located right there and here we have a posterior superior view and that in blue is the sigmoid sinus of droving sinus that goes through the jugular foramen and so there is the jugular foramen here and jugular means neck or throat now why do we have this well we take a look at the jugular foramen and there's a jugular frame in the the sigmoid sinus then becomes the internal jugular vein that courses all the way the neck hence why the vein in the neck the jugular vein goes through the jugular foramen also going through the jugular foramen are three cranial nerves cranial nerves 9 10 and 11 go through that and so there is the jugular foramen for the IJ and cranial nerves 9 10 and 11 in addition we have the frame and Magnum in the word frame and his hole and magnum means really great large big ok it's the biggest frame and or hole the skull and it traverses the spinal cord or the spinal cord goes through that we see the spinal cord come up and right there is a framing magnum it also traverses the vertebral arteries coming off their subclavian artery going up through the transverse foramen of the cervical vertebrae over c1 and ascends up through the foramen magnum and finally the spinal accessory nerve where we see there in yellow coming up through the foramen magnum and it also then goes up over the base of the skull and then descends to the jugular foramen to innervate the traps in sternocleidomastoid but for this moment the spinal accessory nerve there traverses the foramen magnum all right now the hypoglossal canal is located right there now why is it called hypoglossal canal well if we zoom in here we have the spinal cord and the frame in Magnum but off of the medulla spinal cord it's actually from the Dula we got this hypoglossal nerve okay and this hypoglossal nerve is going to then Traverse right there that hypoglossal canal and then right there that hypoglossal nerve courses all the way up below the tongue so the nerve that goes below the tongue because this prefix hypo means under and Glaus all means tongue and so it's called the hypoglossal canal because it is the canal that gives rise to the nerve that goes under the tongue I made you a bit of a tangent here so when I first took anatomy a little while ago in January 1995 is the very first time I took anatomy in my very first lab we learned the skull and I remember when I'm looking at pictures of the skull remember thinking this just looks like a bone than someone shot with a machine gun and said hey why don't you learn all those holes so I had to learn these somehow and I'm not very good at memorizing which is I recognize as ironic because I'm an anatomist so what I did is I printed this off and then I took this and I laminated it and then I took this laminated picture of the skull and I went Shing and I stuck it in my shower so every morning when I was showering I'm like lalala I'm showering I'm actually reading through these looking at this and becoming familiar with the words and then when I was shaving or you know brushing my teeth I'm looking at another picture of the skull when I'm doing some other business in the bathroom I've got other pictures on the wall that I'm reading so every morning I spent like 15 minutes 20 minutes in the bathroom at different stages of getting ready for the morning becoming familiar with the jargon so that it wasn't so the words became familiar I'll tell you since January 1995 I've never forgotten any of the Fremen of the skull and it's kind of funny this picture which of course these are not my bathroom from college but just like my roommates there's never toilet paper in there all right so now let's continue off the tangent and let's continue and they'll show the cranial base and so the cranial base which is the inferior view of the skull let's start with the bones so there's our frontal bones did you just see a little bit of but then there's the zygomatic bones of the cheek from the bottom and I should note that the mandible is removed from this image and then the maxilla that not only forms the upper part of the jaw it also forms part of the hard palate the other part of the hard palate is formed by the palatine bones there on the back of the hard palate so if you run your tongue over the roof of your mouth the hard part is the hard part and then the plucky thing at the back that's your soft palate the vomer bone is here it's at the very back of the nasal septum so in this picture right there I've outlined the nasal septum in the vomer bone is the back part and it gets its name because vomer is Latin for plowshare so and we now take a look she we see that a plowshare blade looks just like the vomer bone hence the name now the sphenoid bone forms part of the base of the skull there in yellow and then the parietal bones you can see forming part of the wall and then the temporal bones a good chunk of them form the base of the skull as well as our zip it'll bone okay so some of the landmarks well let's zoom in there's the incisive foramen there that gives rise to the incisive nerve that supplies part of the hard palate now the incisive nerve and arteries are formed by our nasal palatine nerve and sphenoid palatine artery that come together at the incisive frame and becoming the incisive of nerve and artery and they supply part of the anterior portion of the hard palate that's a picture that I drew in grad school like 20 years ago all right so now there's the greater Palatine foramen greater because it's bigger Palatine is on the palate and it's a hole and this supplies much of the mucosa of the hard palate so this is a views if you're open your mouth really wide and the upper part showing the maxillary teeth there's the greater Palatine foramen giving rise to the greater Palatine nerve an artery that supplies the hard palate if you have a grater you must have a lesser Palatine foramen and that is located right here and it gives rise to the lesser Palatine nerve that does sensation to the soft palate that clucky part of the back of your palate so now the pterygoid process of the sphenoid bone is right there and it has the following parts the medial plate of the pterygoid process the ham ulis which means hook where the tensor veli palatini hooks around and then the lateral plate of the pterygoid process of the sphenoid bone in the house that Jack built now that lateral plate helps with our pterygoid muscles so not our temper Allison mastered it but I just show those as references because if we do this dissection and go Shing and cut that out there's our lateral pterygoid and our medial pterygoid muscles and the lateral pterygoid and medial pterygoid attach laterally immediately to the lateral plate all right so now okay so now let's talk about the mandibular fossa which is located there in the temporal bone and so this mandibular fossa articulates with the mandibular condyle there to give us our temporal mandibular joint so the key to it is right there at the mandibular fossa is the as the part of the temporal mandibular joint now the petrol tympanic fissure is located right there it's located between our mandibular fossa and the carotid canal is one way to find it now the petrol tympanic fissure gives rise to the chorda tympani nerve that goes right through that petrol tympanic fissure right there and supplies taste to the front of the tongue and parasympathetics to our submandibular and sublingual salivary glands it gets its name because the court attempt any nerve courses through the petrous part of the temporal bone Rock and across the eardrum the tympanic membrane hence the name petro tympanic fissure for the course of the court attempt any nerve that exits this opening now the frame a'l valley we look at the basis cover like where is an oval looking foramen there it is that's overlooking and then just to the side and posterior to it is this very tiny one there the frame and spine OSEM and then medial to the frame '''l valley is where we find that freeman lacerum and then there behind right behind the framings by no 'some is our carotid canal now the carotid canal again here we see a lateral view of the neck from grey's anatomy and there is our internal carotid artery and so what happens at the base of the skull is the internal carotid artery goes through the carotid canal there and then into the cranial vault at the exit of the carotid canal there so there is the carotid canal that is its bottom opening into the carotid canal which is where the yellow arrow is pointing so now the jugular foramen is located just behind the carotid canal and the styloid process of the temporal bone there it is where that word styloid is Greek for pillar like the very pointy landmark is shown there in this lateral view of the skull but you have but you may have if you're studying osteology recognized i've heard that word styloid before it's the styloid process of the radius and styloid process of the ulna it just means pillar-like styloid process in this case of the temporal bone it's where you've got muscles and ligaments attaching to it now the mastoid process of the temporal bone is located there reminders that bump right behind the ear and then there is a opening and anatomist said what do we call this opening between the styloid process and mastoid processes I know we'll call it the stylo mastoid foramen and that gives rise to the facial nerve and so the facial nerve goes through the internal acoustic meatus and then gives rise to the facial nerve proper branch that descends through the facial canal and then that facial nerve proper courses down through the facial canal through the bottom of the skull through the style of mastoid foramen through the parotid gland and that facial nerve proper innervates all these muscles of facial expression there's a style of mastoid framing all right so now the foramen magnum is this really big opening on the base of the skull where you see vertebral arteries cranial nerve 11 and the spinal cord so the occipital condyles are here and occipital means occipital bone and condyles are these knobs and they articulate with v1 now let's talk about a different subject not different we're going to continue but let's look at something called the cranial fossa which are three large stare like depressions in the floor of the cranial cavity so here we have the anterior middle and posterior cranial fossa but it's hard to see these stare like depressions so let's take a look at the same thing from a midsagittal lateral view there's our anterior cranial fossa middle cranial fossa and posterior cranial fossa however you don't really in in the Health Sciences look at too many illustrations like this and often what you see is it's through an x-ray now to see and appreciate the x-ray let's do the following let's take a look and I'm going to draw a vertical horizontal lines excuse me from the floor of each of these three fossa okay and then what we're gonna do is with an x-ray which flattens everything so let's just take this image and go it yeah and I didn't completely flatten it but it's flattened enough so what happens is when you're looking at the front of an x-rays with the illustrations on the left are showing and what the view is what you see is this x-rays notice what happens there's the level of the anterior cranial fossa and now look at the x-ray there it is that's the anterior cranial fossa now in red there is the floor of the middle cranial fossa there and then in green there's the floor of the posterior cranial fossa so there you get these three stare like depressions in the floor of the cranial cavity so that my friends is showing the skull anatomy in a nutshell [Music]

Channel: The Noted Anatomist

Views: 1,167,105

Keywords: Skull, Suture, Temporal bone, Sphenoid bone, Mandible, Frontal bone, Occipital bone

Id: _In46sgXzBM

Length: 39min 24sec (2364 seconds)

Published: Sat Feb 08 2020