Description

 
This video is about the viscerocranium.
Bones of the skull:
• Neurocranium – surrounds the brain
• Viscerocranium – forms the facial skeleton

Bones included in the viscerocranium:
• Maxilla (maxilla) – paired
• Zygomatic bone (os zygomaticum) – paired
• Palatine bone (os palatinum) – paired
• Nasal bone (os nasale) – paired
• Lacrimal bone (os lacrimale) – paired
• Inferior nasal concha (concha nasalis inferior) – paired
• Vomer (vomer) – unpaired
• Mandible (mandibula) – unpaired
• Hyoid bone (os hyoideum) – unpaired

Maxilla:
• Body (corpus maxillae)
• Maxillary sinus (sinus maxillaris)
• Frontal process
• Zygomatic process (processus zygomaticus maxillae)
• Alveolar process (processus alveolaris)
• Palatine process (processus palatinus)
• Infraorbital margin
• Infraorbital groove (sulcus infraorbitalis)
• Infraorbital canal (canalis infraorbitalis)
• Infraorbital foramen (foramen infraorbitale)
• Canine fossa (fossa canina)
• Canine eminence (eminentia canina)
• Nasal notch (incisura nasalis)
• Maxillary tuberosity (tuber maxillae)
• Alveolar foramina (foramina alveolaria)
• Nasal crest (crista nasalis)
• Conchal crest (crista conchalis)
• Ethmoidal crest (crista ethmoidalis)
• Lacrimal notch (incisura lacrimalis)
• Lacrimal groove (sulcus lacrimalis)
• Greater palatine groove (sulcus palatinus major)
• Dental alveoli (alveoli dentales maxillae)
• Interalveolar septa (septa interalveolaria)
• Interradicular septa (septa interradicularia)
• Palatine grooves (sulci palatini)
• Incisive canal (canalis incisivus)

Zygomatic bone:
• Frontal process (processus frontalis ossis zygomatici)
• Temporal process (processus temporalis ossis zygomatici)
• Orbital surface (facies orbitalis)
• Zygomaticofacial foramen (foramen zygomaticofaciale)
• Zygomaticotemporal foramen (foramen zygomaticotemporale)
• Zygomaticoorbital foramina (foramina zygomaticoorbitalia)
• Zygomatic arch (arcus zygomaticus)

Palatine bone:
• Horizontal plate (lamina horizontalis)
• Perpendicular plate (lamina perpendicularis)
• Pyramidal process (processus pyramidalis)
• Sphenoidal process (processus sphenoidalis)
• Orbital process (processus orbitalis)
• Nasal surface (facies nasalis)
• Palatine surface (facies palatina)
• Maxillary surface (facies maxillaris)
• Nasal crest (crista nasalis)
• Conchal crest (crista conchalis)
• Ethmoidal crest (crista ethmoidalis)
• Sphenopalatine notch (incisura sphenopalatina)
• Greater palatine groove (sulcus palatinus major)
• Greater palatine canal (canalis palatinus major)
• Lesser palatine foramina (foramina palatina minora)
• Greater palatine foramen (foramen palatinum majus)

Lacrimal bone:
• Lacrimal groove (sulcus lacrimalis)
• Lacrimal fossa (fossa sacci lacrimalis)

Nasal bone:
• Internasal suture (sutura internasalis)
• Frontonasal suture (sutura frontonasalis)
• Nasal foramen (foramen nasale)
• Ethmoidal groove (sulcus ethmoidalis)

Inferior nasal concha (concha nasalis inferior):
• Separate bone, distinct from ethmoid conchae
• Increases nasal surface area
• Aids in humidification and filtration of air

Vomer:
• Posterior part of nasal septum
• Articulates with:
– Perpendicular plate of ethmoid (lamina perpendicularis ossis ethmoidalis)
– Maxilla
– Palatine bone
– Sphenoid bone

Mandible:
• Body (corpus mandibulae)
• Ramus (ramus mandibulae)
• Angle (angulus mandibulae)
• Coronoid process (processus coronoideus)
• Condylar process (processus condylaris)
• Head of mandible (caput mandibulae)
• Neck of mandible (collum mandibulae)
• Mandibular notch (incisura mandibulae)
• Fovea for lateral pterygoid (fovea pterygoidea)
• Mental foramen (foramen mentale)
• Alveolar part (pars alveolaris mandibulae)
• Mental protuberance (protuberantia mentalis)
• Mental tubercles (tubercula mentalia)
• Oblique line
• Mandibular symphysis (symphysis mandibulae)
• Superior mental spines (spinae mentales superiores)
• Inferior mental spines (spinae mentales inferiores)
• Mylohyoid line
• Sublingual fossa (fovea sublingualis)
• Submandibular fossa (fovea submandibularis)
• Mylohyoid groove (sulcus mylohyoideus)
• Mandibular foramen (foramen mandibulae)
• Mandibular canal (canalis mandibulae)
• Digastric fossa (fossa digastrica)

Hyoid bone (os hyoideum):
• Body (corpus ossis hyoidei)
• Greater horns (cornua majora)
• Lesser horns (cornua minora)

Sources:
Standring S. (2020). Gray’s Anatomy, 42nd ed.
Tubbs RS, Shoja MM, Loukas M. (2016). Bergman’s Encyclopedia of Human Anatomic Variation.
White TD, Folkens PA. (2005). The Human Bone Manual.

Programs: Complete Anatomy, Biorender, Powerpoint

Transcript

 
Introduction
0:00
In the previous video, we covered the bones of the neurocranium, the part of the skull
0:04
that protects the brain. But what about the bones that shape our face, hold our teeth,
0:08
and form the structure of our nasal cavity and orbits? That’s where the viscerocranium comes in.
0:14
While the neurocranium safeguards the brain, the viscerocranium is responsible for everything we
0:20
recognize in a person’s face – from the curve of the cheekbones to the structure of the jaw.
0:25
In this video, we’ll go through each of these facial bones, their key landmarks,
0:30
and their role in function and aesthetics. We’ll also look at how these bones interact
0:35
to form openings and passageways for nerves, blood vessels, and sensory organs – all of which
0:41
are critical for sight, smell, and taste. And in the next video, we’ll cover the
0:46
joints and sutures of the skull. Hey everyone, my name is Taim. I’m
0:50
a medical doctor, and I make animated medical lectures to make different topics in medicine
0:54
visually easier to understand. If you’d like a PDF version or a quiz of this presentation, you can
Bones of the Skull
0:59
find it on my website, along with organized video lectures to help with your studies.
1:04
Alright, let’s get started! As we said earlier, the bones of the skull are
1:08
divided into two main regions: the neurocranium and the viscerocranium. The neurocranium consists
1:14
of all the bones that enclose and protect the brain, which we covered in the last video.
1:19
Now, let’s shift our focus to the viscerocranium, which is highlighted here in green. These are
Viscerocranium
1:24
the bones that shape the face and support crucial functions like chewing, speaking,
1:29
and breathing. Let’s go ahead and highlight them. We have the Maxilla, the Zygomatic bone,
1:34
Palatine bone, which we can’t fully highlight yet because it’s embedded within the skull,
Maxilla
1:39
the Lacrimal bone, Nasal bone Inferior nasal concha, Vomer, and the lower jaw or Mandible.
1:46
These are the bones we’ll be covering in this video, so let’s start with the maxilla.
1:50
The maxilla is also known as the upper jaw, and it’s such an important bone in
1:55
the viscerocrnaium. It’s involved in forming the orbit, nose and palate,
2:00
holds the upper teeth and plays an important role for chewing,
2:04
speaking, and facial aesthetics. Now, let’s break it down. The
2:07
maxilla consists of a central body and four distinct processes that extend from it.
2:13
The body of the maxilla is its core, pyramidal structure, containing a hollow space called
2:18
maxillary sinus that plays a role in reducing the weight of the skull and humidifying inhaled air.
2:25
Superiorly, we have the frontal process, which extends up to articulate with the frontal bone.
2:31
Laterally, we find the zygomatic process, which connects the maxilla to the zygomatic bone.
2:36
Inferiorly, there’s the alveolar process, which forms the upper
2:40
dental arch and holds the upper teeth in place. Medially, if we look from an inferior perspective,
2:46
we can see the palatine process, which contributes to forming the hard palate,
2:50
or the roof of the oral cavity. For orientation, let’s look at the
2:54
maxilla in relation to other bones. Above is the Frontal bone, laterally is the Zygomatic bone,
3:01
below the Mandible, Then forming the posterior part of the hard palate is the
3:06
Palatine bone , dividing the nasal cavity is the Vomer, we can see the pterygoid processes
3:11
of the Sphenoid bone extending downwards, and then at the back is the Occipital bone.
3:17
Now that we have the big picture, let’s dive deeper into the detailed landmarks of the maxilla.
3:23
Here I’ve grayed out all the other bones so we can focus solely on the maxilla. This bone
3:28
has several surfaces: the orbital surface, anterior surface, infratemporal surface,
3:34
and the nasal surface. Below, we can still see the palatine process of the hard palate
3:39
and the alveolar process. For orientation. Now, let’s isolate the maxillary bone from an
3:46
anterior view and then from an inferior view. Here, I’ve already highlighted
3:50
some important structures. First up is the infraorbital margin, which marks
3:55
the lower boundary of the orbital cavity. Just beside it, we find the anterior lacrimal crest,
4:01
a ridge that plays a role in forming the lacrimal fossa, containing the lacrimal sac,
4:06
think of it as the tear drainage system. Then there’s a groove called the infraorbital
4:12
groove. This groove leads into the infraorbital canal, which transmits the infraorbital nerve
4:17
and vessels. These structures exit onto the face through the infraorbital foramen, providing blood
4:24
supply and sensation to the mid-face region. We also have the canine fossa, which is a
4:29
deep depression above the canine tooth, and the canine eminence, a bony ridge over the root of
4:35
the canine tooth. Next, bordering the nasal cavity is the nasal notch, contributing to
4:41
the pear-shaped opening of the nasal aperture. If we now rotate the maxilla in this direction
4:47
to view the infratemporal surface, we will see the maxillary tuberosity, a rounded area behind
4:54
the last molar tooth. This region contains small openings called the alveolar foramina, that allow
5:01
the passage of the posterior superior alveolar nerves and vessels, supplying the upper molars.
5:07
Turning the bone a little further in this direction, we can see the nasal surface,
5:12
forming part of the lateral wall of the nasal cavity. Here, we can find the nasal crest,
5:18
which articulates with the vomer to form the nasal septum. There’s also the conchal crest,
5:23
which articulates with the inferior nasal concha, and the ethmoidal crest, which connects
5:28
with the middle nasal concha. The lacrimal notch here leads into the lacrimal groove,
5:34
containing the nasolacrimal duct, which is our tear drainage pathway. So tears are produced by
5:40
the lacrimal gland in the upper lateral parts of the orbits, then when there’s so much tears
5:45
that overflows the eyes, some of those tears make their way through the lacrimal notch and
5:51
lacrimal groove, within the lacrimal duct, to take the tears towards your nasal cavity.
5:56
That’s why the nose sometimes runs when tears are being produced. Alright, additionally,
6:01
we have the greater palatine groove which runs posteriorly, transmitting the greater
6:06
palatine nerve and vessels toward the palate . Now, let’s talk about this large cavity within
6:11
the maxilla, called the maxillary sinus. Sinuses are air-filled spaces that lighten
6:18
the weight of our skulls and help humidify the air we breathe. We have several sinuses in our heads,
6:24
and the maxillary sinus is one of them. It’s the largest paranasal sinus and plays a role
6:29
in voice resonance and reducing skull weight. Now, let’s look at the skull from an anterior
6:35
perspective, then cut the skull like this, and look from this direction,
6:39
we will be able to see the maxillary sinus and its opening, the maxillary hiatus. This opening
6:45
allows mucus to drain into the middle nasal meatus of the nasal cavity. Now for orientation,
6:51
we can see the inferior nasal concha, middle nasal concha, and between them is the middle nasal
6:57
meatus and below is the inferior nasal meatus. Let’s now look at the maxilla from an inferior
7:04
view again, and highlight structures from this view. We can see the maxillary tuberosity and
7:09
the greater palatine groove again. But, we can also see the dental alveoli of the maxilla,
7:15
or also known as the alveolar cavities. These are small spaces along the lower part of the maxilla
7:21
that hold the roots of the teeth, with their shape varying based on the type of tooth. In adults,
7:27
there are normally eight dental alveoli on each maxilla, giving a total of sixteen dental
7:33
alveoli found across the entire maxillary alveolar arch. Two adjacent dental alveoli
7:39
are separated from each other by interalveolar septa and the dental alveoli for some teeth are
7:45
subdivided by interradicular septa in order to accommodate teeth that have more than one root.
7:51
Other things we can see are the palatine grooves, which are the two curved,
7:55
shallow depressions found along the palatine surface of the maxilla. They
7:59
contain the greater palatine nerve and vessels, and lead them towards the greater palatine canal.
8:05
Then we can see the incisive canal, which is the canal that connects the nasal cavity with
8:10
the oral cavity, and it transmits the nasopalatine nerve and a branch of the sphenopalatine artery.
8:16
— So that was
Zygomatic Bone
8:17
the maxilla. Next, let’s do the zygomatic bone, which is also called our cheekbone.
8:23
It consists of a lateral surface, which forms the most prominent part of the cheek
8:27
and provides attachment for facial muscles; a frontal process, which extends superiorly to
8:33
articulate with the frontal bone, contributing to the lateral rim of the orbit; an orbital surface,
8:39
which forms part of the inferior and lateral wall of the orbit, helping support the eye;
8:43
and a temporal process, which extends posteriorly to connect with the zygomatic process of the
8:49
temporal bone to form the zygomatic arch. The zygomatic arch serves as the attachment
8:55
site for the masseter muscle, one of the main muscles of mastication, which plays a crucial
9:00
role in chewing by elevating the mandible. It also helps define the shape of the face
9:06
If we look at the skull from this view, we can also see the temporal surface, located
9:11
posteriorly, which forms part of the infratemporal fossa, a region that contains important structures
9:17
like the maxillary artery and pterygoid muscles. In this region, the zygomatic bone has two
9:23
foramina, called the zygomaticoorbital foramina, which transmit the zygomatic nerve
9:28
and accompanying vessels to innervate and supply the skin over the cheek and temple. At the front,
9:34
we can see the zygomaticofacial foramen, which allows passage of the zygomaticofacial
9:39
nerve and vessels to supply the skin over the prominence of the cheek.
9:44
Now, if we go back to this view again and focus on the temporal surface, we can see the
9:49
zygomaticotemporal foramen, which transmits the zygomaticotemporal nerve and vessels to supply the
9:56
skin over the anterior temporal region. So that was the zygomatic bone.
Palatine Bone
10:01
Next, we have the palatine bone. The palatine bone is interesting, this is an L-shaped bone located
10:09
behind the palatine process of the maxilla. Let’s now go ahead and isolate it. This L-shaped bone
10:15
consists of a horizontal plate and a perpendicular plate. The horizontal plate forms the posterior
10:22
part of the hard palate, while the perpendicular plate extends vertically and contributes
10:27
to the lateral wall of the nasal cavity. Other parts we can see is the pyramidal process,
10:32
which goes backward and fits between the pterygoid plates of the sphenoid. We have
10:37
the sphenoidal process, which articulates with the sphenoid bone; and the orbital process,
10:42
which contributes to the floor of the orbit. To make it easier to orient, it’s important
10:49
to remember these surfaces. The nasal surface faces the nasal cavity. Palatine
10:54
surface faces the oral cavity, Maxillary surface articulates with the maxilla and
11:00
contributes to the pterygopalatine fossa. Now, let’s go over some landmarks. We have
11:06
something called the Nasal crest, where the vomer articulates to form the nasal septum,
11:11
we have the Conchal crest, where the inferior nasal concha attaches, the ethmoidal crest, where
11:17
the middle nasal concha attaches, sphenopalatine notch, which is a gap at the superior border that,
11:23
with the sphenoid bone, forms the sphenopalatine foramen, allowing passage of the sphenopalatine
11:29
artery and nasopalatine nerve. Then we can see the greater palatine groove, which is a channel
11:35
on the inferior surface that, when combined with the maxilla, forms the greater palatine canal,
11:41
transmitting the greater palatine nerve and artery to the hard palate.
11:45
Okay. Let’s now take the lacrimal bone, then smash together the contralateral lacrimal bone.
11:51
This is what they look like, lying on the backside of our nasal cavity. Together they form the nasal
11:57
crest that has the posterior nasal spine. This is the dorsal projection of the nasal crest,
12:03
and forms the origin of the muscle of the uvula. And just to orientate again, we can
12:08
see the maxilla here, and the sphenoid bone here. On the nasal crest we can see the vomer. Laterally
12:14
we can see the inferior nasal concha, middle nasal concha and the perpendicular plate up here.
12:21
On the inferior side, we’re looking at the hard palate now. Here, we can see the lesser palatine
12:27
foramina, which are small openings located near the posterior margin of the hard palate,
12:32
transmitting the lesser palatine nerves and vessels. These nerves provide sensory
12:37
innervation to the soft palate. Anteriorly to it, we can see the greater palatine foramina,
12:42
which are larger openings positioned near the second or third molars. These foramina transmit
12:48
the greater palatine nerves and vessels, which supply the hard palate mucosa, palatine glands,
12:54
and the posterior palatal gingiva. So that was the palatine bone. Next let’s do the
Lacrimal Bone
13:01
Lacrimal bone, nasal, inferior concha and vomer. ——-
13:05
The lacrimal bones are the smallest and most fragile bones of the facial skeleton, each
13:11
roughly the size of a fingernail. They are located in the medial wall of each orbit, anterior to the
13:17
ethmoid bone, and they articulate superiorly with the frontal bone and anteroinferiorly with the
13:23
maxilla. Now, when you look at the lacrimal bone, you’ll immediately notice a groove, and this is
13:29
called the lacrimal groove, which, together with the maxilla, forms the lacrimal fossa.
13:35
This fossa contains the lacrimal sac, which is an important component of the tear drainage system.
13:41
So tears collect in the lacrimal sac and drain through the nasolacrimal duct into the inferior
13:47
nasal meatus of the nasal cavity, explaining why excessive tearing can lead to a runny nose.
Nasal Bone
13:53
Nasal Bone The nasal bones are two
13:55
small elongated bones that form the bridge of the nose. They articulate medially with
14:01
each other at the internasal suture, superiorly with the frontal bone at the frontonasal suture,
14:07
laterally with the frontal processes of the maxillae, and posteriorly with the perpendicular
14:12
plate of the ethmoid bone. On the external surface, we can see a very small hole called
14:18
the nasal foramen, which allows for the passage of small emissary veins. Otherwise the nasal bone
14:25
provides attachment for the procerus and nasalis muscles, which are involved in facial expressions.
14:31
On the internal surface, as we see here, we can find a groove called the ethmoidal groove,
14:36
for the anterior ethmoidal nerve, contributing to the innervation of the nasal mucosa.
14:42
Inferior Nasal Concha Then we have the inferior nasal conchae,
Inferior Nasal Concha
14:45
these are independent bones that project from the lateral walls of the nasal cavity.
14:51
They are distinct from the superior and middle nasal conchae which are parts of the ethmoid bone.
14:56
They’re all covered by mucous membranes, and they all increase the surface area of the nasal cavity,
15:03
enhancing the warming, humidification, and filtration of inhaled air. They also play a role
15:09
in directing airflow and facilitating the drainage of the nasolacrimal duct into the nasal cavity.
15:15
Vomer Then we have vomer. This is a singular bone
Vomer
15:20
that forms the posterior-inferior portion of the nasal septum, separating the two nasal cavities.
15:27
It articulates superiorly with the perpendicular plate of the ethmoid bone, inferolaterally with
15:33
the maxillae and palatine bones, and posteriorly with the sphenoid bone. So that was it for all
15:39
of these bones, now, let’s cover the detailed anatomy of the lower jawbone, or the mandible.
Mandible
15:45
Mandible The mandible is the largest and strongest
15:48
bone of the face. It consists of two parts mainly, we have a ramus of the mandible on either side,
15:55
and a horizontal body of the mandible.​The ramus is the vertical extension on each
16:01
side of the body.The first noticeable thing we can see is this prominent angel of the mandible.
16:07
And if you look closely, you’ll find two processes on the superior part of the ramus. One called the
16:14
Coronoid Process, which is a thin, triangular eminence that serves as the insertion point
16:19
for the temporalis muscle, and we can see the Condylar Process. This process consists of the
16:25
head of the mandible, which articulates with the mandibular fossa of the temporal bone to
16:30
form the temporomandibular joint (TMJ), allowing movements essential for chewing and speaking. It
16:37
consists of a neck of the mandible, that supports the head, and contain a fovea, which is a small
16:43
depression on the anterior surface of the neck where the lateral pterygoid muscle inserts.
16:49
Between the coronoid and condylar processes is the mandibular notch, a concave area that
16:55
allows passage of the masseteric nerve and vessels to the masseter muscle.
16:59
Now, what else can we see here? The angle of the mandible is the area where the body and
17:04
ramus meet, and on the outer edge we can see the rough masseteric tuberosity, which provides the
17:11
insertion point of the masseter muscle. ​—
17:14
Now let’s cover the structures associated with the body of the mandible.
17:18
On the inferior side, we can see the rounded base of the mandible, which provides structural support
17:24
and serves as an attachment for several muscles involved in jaw movement. Up here, we have the
17:29
alveolar part, which contains the dental alveoli, containing the roots of the lower teeth. This part
17:36
of the mandible is constantly remodeled throughout life in response to tooth eruption and loss.
17:42
Then we can see the mental foramen, a small but important opening located below the
17:47
second premolar tooth on each side. This foramen transmits the mental nerve and mental vessels,
17:54
which are responsible for sensory innervation to the skin of the lower lip, chin, and the labial
18:00
gingiva of the mandibular incisors and canines. Let’s now highlight some important landmarks.
18:06
The first thing we notice is the mental protuberance, which is the bony prominence
18:11
at the front of the mandible forming the chin. It is more pronounced in some individuals and
18:17
contributes to the overall shape of the lower face. On either side of the mental protuberance,
18:22
we can see the mental tubercles, these are small elevations that add to the contour of the chin.
18:29
Then we have the oblique line of the mandible, a ridge that runs from the mental foramen
18:35
upward toward the ramus. This serves as an attachment for the depressor anguli oris
18:40
and depressor labii inferioris muscles, which help in moving the lower lip. In the midline,
18:46
we can also see the mandibular symphysis, which represents the fusion site of the two halves
18:52
of the mandible during early development. Now, let’s look at the mandible from the
18:57
inside. Even here, we can still see the mandibular symphysis, extending along the entire midline of
19:03
the mandible. Now let’s start with the landmarks from the midline and then continue outwards.
19:08
The first things we can see are the superior and inferior mental spines, or also called
19:14
genial tubercles, which serve as attachment points for the genioglossus and geniohyoid
19:19
muscles. Those are two important muscles involved in tongue movement and swallowing.
19:25
Moving laterally, we find the mylohyoid line, this is a ridge that runs obliquely along the
19:31
inner surface of the mandible, which serves as the attachment for the mylohyoid muscle,
19:36
a major muscle of the floor of the mouth that supports the tongue. Just above this line,
19:41
there is the sublingual fossa, which provides space for the sublingual gland. Below the
19:47
mylohyoid line, there is the submandibular fossa, which contains the submandibular gland,
19:52
one of the three major salivary glands. On the sides, we have the mylohyoid groove, which
19:58
runs downward and forward from the mandibular foramen and transmits the nerve to mylohyoid,
20:04
a branch of the inferior alveolar nerve. Now, the mandibular foramen is a large opening on the inner
20:12
surface of the ramus of the mandible, serving as the entry point for the inferior alveolar nerve,
20:18
artery, and vein, which travel through the mandibular canal to supply the lower teeth.
20:24
Now, let’s go ahead and add some muscles. Here we can see the mylohyoid muscle attached to the
20:30
mylohyoid line. But we can also see another muscle attaching to the inferior surface of the mandible,
20:36
near the midline. This attachment point is called the digastric fossa,
20:40
and it serves as the origin for the anterior belly of the digastric muscle, which plays a
20:45
role in depressing the mandible and elevating the hyoid bone during swallowing and speaking.
20:51
So that was all of these bones. Now, lastly, this is debatable,
Hyoid Bone
20:57
but in some sources, you might find that the hyoid bone and the ear ossicles are considered
21:02
part of the viscerocranium. So let’s just go over the hyoid bone very quickly.
21:07
The hyoid bone is a very unique bone, it floats beneath the mandible, and is suspended by muscles
21:14
and ligaments, without directly articulating with any other bones. But! It is so important
21:20
because it stabilizes structures in the neck and provides a solid base for the tongue, larynx,
21:26
and pharynx. It plays a role in swallowing, speech, and maintaining the airway by serving
21:31
as an attachment point for lots of muscles. As you can see here, many muscles attach to
21:36
it. There are the suprahyoid muscles, such as the mylohyoid, digastric, and stylohyoid,
21:42
which help elevate the hyoid bone and assist in swallowing. Then we have the infrahyoid muscles,
21:48
including the thyrohyoid and sternohyoid, which depress the hyoid bone and stabilize the larynx.
21:55
Notice also how the hyoid bone sits directly above the larynx, or the voice box. This relationship is
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crucial because movements of the hyoid bone directly affect the position of the larynx,
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which is important for phonation, or speech. So, let’s go ahead and isolate this bone.
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The hyoid bone consists of three main parts. First, there is the body of the hyoid bone,
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which is the central portion, providing attachment for the geniohyoid, mylohyoid,
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and sternohyoid muscles. Then, we have the greater horns, which goes posteriorly and slightly upward,
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serving as attachment sites for muscles such as the hyoglossus and thyrohyoid. Lastly, we have the
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lesser horns, which are very tiny projections near the junction of the body and greater horns. These
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act as attachment points for the stylohyoid ligament, which suspends the hyoid bone from
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the styloid process of the temporal bone. Alright, we finally managed to go through
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the detailed anatomy of all the bones of the viscerocranium. In the next video,
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we’ll look at all the joints of the skull, and cover the sutures as well.
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23:09
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23:14
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