Bones of the skull and more skull anatomy
Summary
TLDRThis educational video script delves into the intricacies of the human skull, focusing on sutures and bony landmarks. It explains the purpose of sutures like the coronal, sagittal, and lambdoid, and highlights features such as fontanels, which allow for brain growth and ease of childbirth. The script also covers various bony processes and fossae, emphasizing their roles in muscle attachment and housing blood vessels and nerves. The goal is to familiarize viewers with anatomical terms and structures, enhancing their understanding of the skull's complex architecture.
Takeaways
- 💀 The video discusses the anatomy of the human skull, focusing on sutures and bony landmarks.
- 🔍 The sutures are the seams between the bones of the skull, including the coronal, sagittal, lambdoid, and squamosal sutures.
- 👶 Fontanels are soft spots in the skull of infants, allowing for brain growth and facilitating birth.
- 🦴 The skull has various bony processes, such as the mastoid process and the zygomatic process of the temporal bone, which are important for muscle and ligament attachments.
- 👂 The external acoustic meatus is the opening for the ear, located near the mastoid process.
- 👁️ The sphenoid bone is a key part of the skull, with various sutures connecting it to other bones, such as the frontal and parietal bones.
- 🦷 The mandible articulates with the temporal bone at the mandibular fossa, with the condylar process being the articulating part.
- 🧠 The cranial fossae are depressions in the skull that house different parts of the brain, including the anterior, middle, and posterior cranial fossae.
- 🩺 The internal structures of the skull, such as the sella turcica, are important for the location of the pituitary gland and passage of blood vessels.
- 🦷 The palate is formed by the maxilla, palatine bones, and the sphenoid bone, with the hard palate being a significant structure.
- 🕳️ Foramina in the skull, such as the greater and lesser palatine foramina, are passageways for nerves and blood vessels.
Q & A
What is the main focus of the video script?
-The main focus of the video script is to discuss the anatomy of the skull, specifically the sutures and various bony landmarks, as well as the anatomical terms associated with them.
What are sutures in the context of the skull?
-Sutures are the fibrous joints between the bones of the skull that allow for growth and provide protection to the brain. They are immovable and have a tight interdigitated structure.
What does the term 'coronal suture' refer to?
-The coronal suture is the suture that separates the frontal bone from the two parietal bones and lies in the coronal plane.
What is the sagittal suture, and what does its name signify?
-The sagittal suture is the suture that separates the two parietal bones in the midline. Its name comes from 'Sagittarius the Archer,' symbolizing the straight path of an arrow, which is similar to the suture's direction.
What is the significance of the lambda and bregma in the skull?
-Lambda is the point where the lambdoid suture meets and forms a Y-shape, while bregma is where the sagittal suture meets the coronal suture, forming a T-shape. These points are important anatomical landmarks on the skull.
What are fontanels, and why are they important in infants and fetuses?
-Fontanels are large spaces between the bones of the skull in infants and fetuses, allowing for the rapidly expanding brain to grow without the bones impeding its growth. They also facilitate the molding of the skull during birth for easier passage through the birth canal.
What is the function of the mastoid process and the styloid process in the skull?
-The mastoid process is a bony projection from the temporal bone, and the styloid process is a thin, elongated projection that serves as an attachment point for various muscles and ligaments, including the stylohyoid ligament to the hyoid bone.
What is the purpose of the sphenoid bone in the skull?
-The sphenoid bone is a central bone in the skull that forms part of the眼眶 and the base of the skull. It also houses the pituitary gland and provides attachment points for various structures, including the tentorium cerebelli.
What are the anterior and posterior cranial fossae, and what do they contain?
-The anterior cranial fossa is the space above the sphenoid bone, housing the frontal lobes of the brain. The posterior cranial fossa is located at the back of the skull, containing the cerebellum and brainstem.
What is the function of the pterygoid plates in the skull?
-The pterygoid plates are parts of the sphenoid bone that serve as attachment points for the muscles of mastication, including the lateral and medial pterygoid muscles.
What are the ethmoid bone and its significance in the skull?
-The ethmoid bone is a light, spongy bone located in the orbit of the skull, forming the upper part of the nasal cavity and contributing to the formation of the eye socket.
Outlines
💀 Skull Anatomy and Sutures
This paragraph delves into the intricacies of the human skull, focusing on the sutures and bony landmarks. It begins with an introduction to the frontal, parietal, occipital, and temporal bones, highlighting the coronal, sagittal, and lambdoid sutures that interconnect them. The discussion includes the significance of fontanels in infants, which allow for brain growth and skull flexibility during birth. The paragraph also touches on the zygomatic arch, mastoid process, and styloid process, emphasizing their roles in the attachment of muscles and ligaments. The importance of sutures as protective, immovable joints for the skull's contents is underscored.
🦴 Exploring Skull Features and Landmarks
The second paragraph continues the exploration of the skull, identifying specific bony features such as the zygomatic process of the frontal bone, the frontal process of the zygomatic bone, and the ethmoid bone within the orbit. It discusses the sphenoid bone's position and the surrounding sutures, including the sphenofrontal and spheno parietal sutures. The paragraph also describes the external and internal occipital protuberances, the superior and inferior nuchal lines, and the attachment sites for neck muscles. The inner skull structures are highlighted, including the anterior, middle, and posterior cranial fossae, and the sphenoid bone's role in the skull's interior.
🗝️ Skull Sutures and Their Functional Significance
This paragraph examines the functional aspects of skull sutures, their variability among individuals, and their purpose in protecting the brain. It describes the external occipital protuberance and the nuchal lines, which serve as attachment points for muscles that support the head. The paragraph also details the internal structures of the skull, such as the anterior and posterior clinoid processes that form a groove for the internal carotid artery. It explains the importance of the sphenoid bone in the skull's interior, the presence of the pituitary gland in the hypophyseal fossa, and the role of the clivus and dorsum sellae in the skull's posterior wall.
🦷 Mandible and Skull's Bony Intersections
The final paragraph shifts focus to the mandible and its connection to the skull, specifically the mandibular fossa and the temporomandibular joint. It describes the condyloid process, coronoid process, and the body, angle, and ramus of the mandible. The paragraph also discusses the muscles of mastication, particularly the masseter muscle, and the structures passing through the mandibular foramen to the lower teeth. It concludes with a mention of the mental foramen and the mylohyoid muscle, emphasizing the complexity of the skull's bony intersections and the importance of understanding these anatomical details.
Mindmap
Keywords
💡Skull
💡Sutures
💡Fontanels
💡Bony Processes
💡Zygomatic Arch
💡Mastoid Process
💡Sphenoid Bone
💡Occipital Bone
💡Cranial Fossae
💡Dura Mater
💡Styloid Process
💡Mandible
Highlights
Introduction to the anatomy of the skull, focusing on sutures and bony landmarks.
Explanation of the coronal suture and its position on the skull.
Description of the sagittal suture and its significance in the midline of the skull.
Identification of the lambdoid suture and its Y-shaped structure at the back of the skull.
Discussion on lambda, bregma, and fontanels in the context of skull development.
Mention of the sphenoid bone and its role in the skull's structure.
Explanation of the squamosal suture and its relation to the temporal bone.
Description of the zygomatic arch and its formation by the zygomatic and temporal bones.
Identification of the mastoid process and its anatomical landmarks.
Discussion on the external and internal occipital protuberances and their significance.
Overview of the cranial fossae and their locations within the skull.
Explanation of the sphenoid bone's role in the middle cranial fossa and its surrounding structures.
Identification of the ethmoid bone and its position within the skull.
Discussion on the importance of sutures in protecting the brain and their individual characteristics.
Description of the attachment points for muscles and ligaments on the skull.
Explanation of the styloid process and its associated structures.
Identification of the pterygoid processes and their relation to the muscles of mastication.
Overview of the mandible's anatomy, including the mandibular fossa and its articulation points.
Conclusion summarizing the importance of understanding skull anatomy for medical and educational purposes.
Transcripts
[Music]
all
look at that these hands are coming out
really nicely
now but I don't actually want to talk
about the hand today I'm going to go
back to the
skull right um so we were talking about
the skull so I thought I'd do a little
bit more about the skull but um talk
about the sutures just go over the
sutures and some of the Bony bits the
protuberances the lumpy bits that we see
um cuz they often get emitted often we
use the names the terms pop up we talk
about muscles attaching to this and
ligaments attaching to that and I'll try
not to give you an exhaustive list of
what attaches to things I'll just try to
point out the Bony bits um so that when
you come across those terms you know
what people are talking about all right
cuz there's quite a lot going on in here
all right I got I got a skull that's got
colored bones which is very helpful and
I've got a decent quality skull
got my skeleton they're always taller
than me these
skeletons so let's use this skull with a
different colored Bones on it cuz it's
quite easy to see where the sutures are
generally right so here's the frontal
bone here are the two pretal
bones here's the occipital bone and
here's the temporal bone here's the
Magilla
mandible zygoma and in red here we've
got the sphenoid bone
um and here are the nasal bones here and
so on so
here separating the frontal bone from
the pital bones is the coronal suture
this is the coronal plane right
separating here in the midline
separating the two uh parial bones is
the sagittal suture Sagittarius the
Archer firing arrows right this is the
sagittal plane um and if we look at the
back of the
skull so between so here's the parial
bone here's the occipital bone this is
the lamboid suture now
lamboid means y-shaped and if we look
here where these sutures meet we get a y
shape this is known as Lambda um so this
gets called the lamboid suture where
these sutures meet here kind of forming
a t this gets known as the bregma and uh
in infants and in the fetus we find two
fontanels here right so the bone Bon we
have these large spaces between the
bones and there's also another suture
here the frontal suture in the fetal
skull which disappears in the adult this
is the anterior
Fontanel and this is the posterior
Fontanel and what the fontanels do is
they allow the
uh the rapidly expanding brain to grow
uh and the bone doesn't get in the way
and it keeps up also during birth
there's a little bit of you you can of
molding of the the bones can move around
a little bit so the head can pass
through the birth canal but yeah those
fontanels there between the parietal
bone and the temporal bone we have the
sosal suture
here this is the squamous the
flat part of the temporal bones this is
the squamous part of the temporal bone
and look at this process here if we're
going to talk about processes in a
moment this is the zygomatic process of
the temporal
bone uh and here's the zyg zygoma here
and together they're forming the
zygomatic Arch this being the zyg this
gets called the temporal arch of the
zygomatic bone and they meet now down
here this is an example of why it's
useful to know the parts the Bony Parts
this here is the mastoid process can you
see that so so here that hole there is
the external acoustic
meatus where we find the
external the opening of the external ear
there the external acoustic meatus or
the external auditory meatus and here
see this bony Point here this this is
the styloid
process and this is then the mastoid
process so if this is the occipital bone
here and this is the mastoid process
here this gets called this suture here
the joint between the two gets called
the excip mastoid suture a little
awkwardly maybe this is the squamous
part of the temporal bone and this meets
the sphenoid bone here and this gets
called the spheno squa suture here and
there's see that little suture there so
here's the prial bone here's the the
sphenoid bone and there's a there's a
little short suture there um so this is
the spheno parietal suture in there so
then here of course here's the frontal
bone here's the sphenoid bone this is
the spheno frontal suture here and we
can also see look we've got these other
bony lumps
here which there we go that's a bit
better
unfortunately this is yellow this is
kind of a a mustard yellow but we got
these two colors next to each other so
it's not super clear but here's the
zygoma here's the frontal bone so this
is the zygomatic process here of the
frontal
bone and this is the frontal process of
the zygomatic bone if you wanted to talk
about the magila you could do similarly
so you see this process
here this process of the Magilla passing
to the zygoma would be the zygomatic
process of the Magilla and this process
here extending up to the frontal
bone this would be the frontal
process of the Magilla now we've talked
about these bones here we uh within the
orbit so we've talked about the bones
there's another video about the bones of
the nasal cavity in here to include
these bits the laal bone and the nasal
bones but if we go deeper inside the
orbit we've got another yellow bone in
there do you see how this this is
mustard so this is the frontal bone this
is the the zygoma and in here can you
see there's that other yellow bone it's
not very helpful is it they could have
could have picked more
colors but it's it's this bone here hang
on there you go and my lighting could be
a bit better but you might be able to
hear the pter patter of rain outside
it's dark I've left this a bit late but
you see this bone here so that's the
ethoid bone
and at the back of the orbit we can see
the red of the sphenoid
bone so these sutures are I mean they're
not very Wiggly on this
skull but on this skull and other skulls
you look at the sutures
are see on this SC the sutures are very
torturous they vary between people but
the purpose of the suture is to form a
tight a very tight kind of inter
digitated joint between the bone of the
skull then these are joints that don't
move um so they're protecting the
contents inside so if we turn the skull
around there are a few features on the
occipital bone as well hopefully you can
see some of the lumps and bumps here um
back here and you can you can usually
palpate it on the back of your head
you've got a lump and this is the
external occipital protuberance
here and there are a couple of lines
there are superior nucle lines and
inferior nucle lines
um difficult to see in 2D but there's
the lump there so there's an external
occipital protuberance and often a Crest
running from it and you can see can you
see these lines here and there are lines
here and these are obviously attachment
sides for structures in the neck which
lift your head up and support your head
and that sort of thing of course if
there's an external oipal protuberance
there's going to be an
internal acal protuberance and if we
open up and look inside
here occipital protuberance in there
just again another
lump and of course if we're inside the
skull here we should probably talk about
some of the shapes in here can you see
how we've got a fosser here we have a
fosser here and we have a fosser here so
up here this is the anterior CR anterior
cranial fosser here we have the middle
cranial fosser on either side and back
here is the posterior cranial fosser and
in here we find the sphenoid bone
um don't really so you can see the
sphenoid bone there in red in the middle
so here's forum and
Magnum
so here and if you study a skull you'll
see the
sutures surrounding the edge of the
sphenoid bone in here right in the
middle we talked about uh the CRI form
plate and the Crystal Galley up
here and we looked
at the internal cotted artery as it
appeared here now here this depression
is the cell Tura The Turk saddle this is
uh and the Deep part in here is the
hypop phesal fosser and this is where
the pituitary gland sits surrounded by
all of this bone um we have um kinoid
processes around
here so these two here are the anterior
kenid processes and you can see that
they're forming
this they're forming a
uh uh they're forming a Groove a tube
through which the internal coted artery
passes and pops up about here um we have
a middle kenid process kind of in here
and this is the posterior kenid proc
process here of the cell Tura we also
talk about the dorsum C as this wall
here the posterior wall is the dorsum
cell and the anterior wall is the uh
tuberculum Cellar so around here we have
there's the the optic Canal passes
through
there um you see this slope
here this slope here
we have a
slope and this is called the cleavus
cleavus literally from the words meaning
slope so we have this slope here and on
the cleavus this is where we find the
basil artery um giving off lots of
pontine arteries the ponds is here um so
blood vessels are coming in here towards
the circle of Willis from the for and
Magnum so there's cleavus um this we
talked about this lumpy part part of
bone here is the petus part of the
temporal bone so on the inside and the
petus part of the temporal bone in here
has the inner rear structures within it
remember that all of these grooves and
processes and lumps and bumps that we're
looking at here have a purpose and the
reason that they're there many of the
grooves are formed by blood vessels um
next to the Bone these melal arteries
and some of them like the the groove we
see formed by the internal cored artery
leave some lovely shapes and the holes
are there for blood vessels and cranial
nerves to pass through these other lumps
and bumps which might not be immediately
apparent what they do or why they're
there they're attachment points for um
for the duramater for the thick
connective coverings of the brain so
Mark was removing some brains from some
bodies this week and um one of the
things Mark has to do is is not just
remove the the skull cap the calvarium
but when he goes in he cuts the cranial
nerves as as close as he can um so he
have as much nerve on the brain as
possible but also he he needs to go deep
and find these edges and cut along here
along the edges of the reflections of
the of the thick connective tissues of
the um the duramater which are holding
the brain down so the tentorium cerebell
here holds down the
cerebellum beneath it and what have you
so that's why there are lumps and bumps
here that's what these Kleen oid
processes are for we have bits of
durometer attaching into them holding it
all in place and the durometer of course
supports the brain and the the Dural
Venus
sinuses I mentioned the the the styloid
process here and the number of
structures pass from it like the styo
hyoid ligament to that to the floating
hyoid bone here so Stylo hyoid ligament
passes from the styloid process to the
hyoid bone now the styloid process is um
bolstered a bit on these plastic skulls
because when skulls get dropped
that's the thing that usually breaks but
here's the styloid process here this
skull has been dropped and it's lost the
styloid process on the other side so
when you're looking at skulls watch out
for that
um but also down here we have a number
of interesting shapes around here right
so here's the nasal cavity opening
posteriorly
so you can see the coni in there you can
see those curves of bone um we've got
these look these Wing shaped bits of
bone here so these are the teroid
processes and there are two on either
side and teroid comes from the word
meaning Wings these are wings of bone
like the
pterodactyl um and there is a lateral
plate and a medial plate for each and if
you think about the muscles of
mastication the uh
the teroid the muscles that the lateral
medial teroid they they attach here oops
so what bone do the teroid plates come
from H let's have a look look you can
see how here's the sphenoid bone so the
teroid plates the teroid processes are
part of the sphenoid bone and you can
see vomer in there um and here's the for
and ovali so this is where you'll find
the the oot gangion just around here and
a whole bunch of nerves dropping out and
running around and then we've got the
muscles here's the pallet so up here
we've got the hard
palette and you can see that the purple
is the
Magilla but there's another red here and
that's not actually the sphenoid bone
this red this is this is a a Palatine
bone on either either side so we've got
the Magilla the and then we've got two
Palatine bones forming the hard pallet
and then we' got the sphenoid bone back
here so watch out for those and there
are a number of faram in
here you can see there's a larger hole
here and there's usually a couple of
smaller holes here and this is the
greater Palatine foran the bigger one
and the smaller ones the Lesser Palatine
foramina and you've got um nerves of the
palet and nasal cavity looping around a
blood vessels looping around here
through these holes um up here there's
another
foran in the pallet and that hole there
that's the incisive
fosser what we've got here are lots of
joins between the occipital bone the
sphenoid bone and the temporal bone
and the cracks of bone that we see here
um we have a a teroid canal that opens
near the teroid plates
um through various which various
structures pass through so these cracks
of bone here are the opening of the
teroid canal very difficult to see
they're there but it's very difficult to
actually see you know the entire Canal
or really parts of it just to know that
the openings are there if we take the
mandible
off of course on these skulls this is
the mandibular fosser so we have a
depression in here so but this
depression of course is filled with a
bit of bit of plastic in these models so
this is the the mandibular fosser you
see where we are so here's
the there's the masto process here's the
um zygomatic process of the temporal
bone and in here then that's the
mandibular
fosser
which the mandible is going to
articulate with so we've got the condil
process which is the articulating part
and then we've got the coronoid process
up here which the masseter muscle
inserts
into and um we have the body down here
the angle where it changes angle and
then the Ramos up here Ramos meaning
Branch but this flattened part and we
can see here on this model we've
got uh a nerve the inferior alviola
nerve and we've got blood
vessels passing into the mandibular
foran which are then going to run to the
lower teeth and then out here through
the mental
Forin
um which is this foran
here there's a Groove in here for the
Milo hyoid muscle which is forming the
floor
here and this notch in between the
condil process and the coronoid process
is the
uh the mandibular Notch so you guys know
the names of the bones we've looked at
the sutes and where the sutes meet oh
one thing I did mention is where these
sutures meet here we were talking about
right we have this all these sutures
coming together here this is the teron
PT r i o n
pan teron teroid we're talking about
wings again aren't we but that's the ter
in that space there so we've got that
weakness where the bone gets thin you
have all those sutures meeting um so
we've talked about the sutures talked
about the bones and I've talked about as
many lumpy bumpy bits on here as I can
think of and I didn't really want to
talk about what attaches to what or what
goes through what as we were talking
about it too much cuz then we'll go down
a rabbit hole and we'll never come out
um but I wanted to go over the terms CU
these terms often get thrown up and
students are blank you know what I don't
know what that means so if you've heard
the term and you've seen the term when
it gets brought up somewhere else you'll
know what we're talking about we're
talking about the cranial FY and all
these bits and Bobs in here right there
are other bits and Bobs on here but you
know that's already extending on what we
were talking about last time and what
we'll often talk about in teaching we
often don't go into that much detail um
but there's a bit more detail and you'll
find more detail if you study a skull um
so good luck spend some time with these
things
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