hello anatomy colleagues this is dr alsup and i hope you're having a great day
and if you weren't before i'm sure you will be after you view this video on the wonderful
world of the cranial osteology you need to know regarding the mastication session we will have a
separate video on mandibular osteology so we'll not be discussing the full skull in this video
but there's a lot of good stuff so let's get started all right we're going to start with a
review structure but that's pertinent to this session because it is the foramen that allows
the mandibular nerve or v3 to exit the skull so i want you to take this moment and try to find
the foramen valley located on the greater wing of the sphenoid on your own so take a moment
hopefully you're pointing at it right now and you are locating this as the foramen o valley so this
nice fairly large valley or oval shaped foramen located on the greater wing of the sphenoid all
right it's going to also be the path by which the lesser petrosal nerve exits the skull all right
so there is a lot going on in this slide and we are going to take our time to work through these
structures we are looking at an inferior view of the crania which this photo has been cut off
in this region it's cutting off some of the more posterior portions so we can focus more on this
portion of the image and this complex right here so i'm going to kind of outline this entire region
is going to be the pterygoid process all right so this whole region right here will be the pterygoid
process and it's going to include two plates of bone the more lateral one which i'm only going to
label just a small portion is going to be the lateral plate
and the more medial one will be the medial plate notice that the medial plate has a projection
right here that i'm outlining that is going to be referred to as the pterygoid hamulus and a tendon
of one of the soft palate muscles the tensor belly palatini is going to glide along this hamulus
to kind of change the direction where the tendon will attach
functionally this lateral plate is related to the infra-temporal fossa
in fact it's going to form the medial wall of the infra-temporal fossa and it's important in
terms of attachments of the medial and lateral pterygoid muscles in fact the relationship of
the pterygoid muscles to the lateral plate is where they get their names medial and lateral
the medial pterygoid plate is more related with the pharyngeal region being an attachment point
for the pterygomandibular rephase and one of the attachment points of the superior pharyngeal
constrictor okay we'll come back to this region in just a moment but let's take a break to find
the sphenoid spine and i'm going to outline the sphenoid spine right in this region
and this one's a little bit more difficult to see it's on a much smaller scale than say some of
those pterygoid plates it's going to be near the foramen spinosum as well as the external opening
of the carotid canal so those are two structures that i like to find because i they're easier to
locate in order to find the spine here so it's a spine or a projection so this likely means
something attaches here which is the case and it's going to be the spheno mandibular ligament
okay returning back to the pterygoid process region we're going to look over at this one
that i haven't outlined already they're going to be too fossae located in between the two
plates so this one would be the medial plate on this side and the lateral plate
and so we're going to be looking at this region in between the two plates right here
the pterygoid fossa is going to be the more inferior of the two so i'm going to label
this region right here remember that we're looking at an inferior view here
and the scaphoid fossa is going to be the more superior or more closely related to
the base of the cranium sorry if you heard my email pop up in the background so recall
that the medial pterygoid muscle is going to be located in this general region and the scaphoid
fossa will be the origin site for the tensor valley palatini which is a soft palate muscle
lastly for this slide let's locate the pterygoid canal which is an opening outline a little bit
where it would be located so it's an opening of the sphenoid bone but it's closely related to
the basilar part of the occipital bone right here so i always try to find that and then it's going
to be this opening right where you're entering into the sphenoid region this is where the nerve
of the pterygoid canal which is heading for the pterygopalatine ganglion is going to traverse
this region so that pterygopalatine ganglion is one of the peripheral parasympathetic ganglia
all right let's move to a lateral view of the cranium and we will start with trying to locate
the infra-temporal crest which is going to be located right here what i'm outlining so we
have it here as part of the sphenoid bone but it will also extend towards the temporal bone as well
and it is going to be an attachment site for the temporalis muscle which makes sense
if you think about the main area where the temporalis muscle is going to be located
it makes sense it would have an attachment right about here-ish as well all right we are likely
hopefully familiar with the styloid process at this point if not make sure to review this
this will be an attachment site for various ligaments associated with the tmj and then of
course some other muscles that we've already discussed and some that we've yet to discuss
and lastly on this particular side let's locate the maxillary tuberosity which is going to be
located right here where i'm outlining i always go to the very back of the maxillary teeth and
the the rest kind of the posterior extent of the maxillary bone and it's going to be located
right there it's a little bump in that region so that's going to be the maxillary tuberosity
the medial pterygoid muscle will have an attachment here so that's
kind of that maxillary attachment point that we've talked about for the medial pterygoid
all right let's focus on the zygomatic arch now the zygomatic arch is going to extend from
here-ish to about um here ish sometimes you see it referred to as here sometimes it'll extend all the
way back to this region that we don't need to get into that level of detail we just need to
understand the basics of where the zygomatic arch would be located and it's going to be composed of
the temporal process of the zygomatic bone as well as the zygomatic process of the temporal
bone and they join together you and you know that because you can see a suture right here
and when you add those two processes together you have the zygomatic arch
you can see that the um the zygomatic process of the temporal bone is going to be a lot longer than
the the um the temporal process of the zygomatic bone now note right here that there is an inferior
projection of the zygomatic process or the zygomatic arch which is the articular tubercle
i love the articular tubicule and i love to talk about it this is going to form
the anterior limit of the mandibular fossa which means it's an anterior limit of the tmj
and if we're talking about a tmj dislocation what will often happen is this mandibular condyle
right here will extend anterior to the articular tubercle so it'll kind of go over that bump right
there but there should be ligaments and a capsule all in this region to prevent that from happening
all right so recall that the mandibular fossa is this depression right in this region here
for that mandibular condyle to sit so this is the cranial portion of the temporomandibular joint
it is a smooth area because articular cartilage sits in this region during life
now just posterior to that region is the petro tympanic fissure so just posterior
to the mandibular fossa you can see it is very thin but it's easier to locate if you know where
that mandibular fossa is so always find mandibular fossa and look just posterior for a thin fissure
the corded timpani will exit the skull here and again here is another
view of the styloid process it looks very different when you don't see it projecting
don't see it projecting str in the typical relationship that we are used to so it's
always nice to look at these processes or any of these structures in as many views as possible
lastly let's identify this the superior or proximal attachments of the temporal muscle and
fascia you're going to have two lines here the superior temporal line which is located right
here put an st is going to be an attachment for temporal fascia whereas the inferior temporal line
which i'll put in i t right here is going to be an attachment site for the temporalis muscle and its
tendons itself sometimes the lines are not very obvious but they certainly are on on this
particular donor here so just be aware that there are typically two lines and that the fascia is
going to be associated with the superior temporal line whereas the tendons of the temporalis muscle
will be associated with the inferior alright so that was a lot of good cranial osteology fun
as you review this material and if you have any questions please feel free to reach out to me
or any of my anatomy colleagues thanks for your time and attention and have a great day