Description

This video covers the Division of the Neck Muscles, including their origins, insertions, and classifications.

Division of the Neck Muscles

• Deep Muscles of the Neck
• Lateral Muscles of the Neck
• Suprahyoid Muscles
• Infrahyoid Muscles
• Craniothoracal Muscles

Deep Muscles of the Neck

Longus Capitis (Musculus Longus Capitis)

• Origin: Transverse Processes of C3-C6 (Proc. transversus vertebrae cervicalis III – VI)
• Insertion: Basilar part of Occipital Bone (Pars basilaris ossis occipitalis)

Longus Colli (Musculus Longus Colli)

• Superior Oblique Part
  • Origin: Transverse Processes of C3-C5 (Proc. transversus vertebrae cervicalis III – V)
  • Insertion: Anterior Tubercle of Atlas C1 (Tuberculum anterius atlantis)
• Vertical Part
  • Origin: C5-T3 Body
  • Insertion: C2-C4 Body
• Inferior Oblique Part
  • Origin: T1-T3 Body
  • Insertion: C5-C6 Transverse Process

Rectus Capitis Anterior (Musculus Rectus Capitis Anterior)

• Origin: Lateral Mass of Atlas C1 (Massa lateralis atlantis)
• Insertion: Basilar Part of Occipital Bone (Pars basilaris ossis occipitalis)

Rectus Capitis Lateralis (Musculus Rectus Capitis Lateralis)

• Origin: Transverse Process of Atlas C1 (Processus transversus atlantis)
• Insertion: Lateral Part of Occipital Bone (Pars lateralis ossis occipitalis)

Lateral Muscles of the Neck

Scalenus Anterior (Musculus Scalenus Anterior)

• Origin: Transverse Process of C3-C6 (Proc. transversus vertebrae cervicalis III – VI)
• Insertion: Scalenus Tubercle on 1st Rib (Tuberculum m. scaleni costa primae)

Scalenus Medius (Musculus Scalenus Medius)

• Origin: Transverse Process of C1/C2-C7 (Proc. transversus vertebrae cervicalis I/II – VII)
• Insertion: Surface of 1st Rib (behind scalenus anterior) (Facies superior costae prima)

Scalenus Posterior (Musculus Scalenus Posterior)

• Origin: Transverse Process of C5-C7 (Proc. transversus vertebrae cervicalis V – VII)
• Insertion: Surface of 2nd Rib (Costae II)

Suprahyoid Muscles

Digastricus (Musculus Digastricus)

• Posterior Belly:
  • Origin: Mastoid Notch of Temporal Bone (Incisura mastoidea)
  • Insertion: Tendon inserting at hyoid bone
• Anterior Belly:
  • Origin: Tendon inserting at hyoid bone
  • Insertion: Digastric Fossa of Mandible (Fossa digastrica)

Infrahyoid Muscles

Sternohyoid (Musculus Sternohyoideus)

• Origin: Sternum and Clavicle
• Insertion: Hyoid Bone

Craniothoracal Muscles

Sternocleidomastoid (Musculus Sternocleidomastoideus)

• Origin: Sternum + Clavicle
• Insertion: Mastoid Process + Superior Nuchal Line

Trapezius (Musculus Trapezius)

• Superior Part
  • Origin: Superior Nuchal Line, External Occipital Protuberance, Nuchal Ligament
  • Insertion: Acromial End of Clavicle, Acromion of Scapula
• Middle Part
  • Origin: Spinous Process of C7-T3/T4
  • Insertion: Spine and Acromion of Scapula
• Inferior Part
  • Origin: Spinous Process of T4-T12
  • Insertion: Spine of Scapula

Platysma

• Origin: Pectoral and Deltoid Fascia
• Insertion: Base of Mandible, Lower Lip, Skin around Mouth

Transcript

Introduction
0:00
Hey what’s up.
0:04
Meditay here and in this video, we’re gonna cover all the muscles of the neck.
0:08
Alright so The muscles of the neck can be divided into
0:10
5 groups based on their anatomical location.
0:13
And keep in mind the classification of the neck muscles may vary depending on the source
0:18
you’re studying from, but all the muscles are the same.
0:21
So first are the deep muscles of the neck.
0:24
Those are the deepest close to the vertebra.
0:26
Then we have the Lateral Muscles of the neck.
0:29
The other two groups are related with the hyoid bone.
0:32
The suprahyoid muscles are located above the hyoid bone, and the infrahyoid muscles are
0:36
located below the hyoid bone.
0:38
And notice that both groups attach to the hyoid bone.
0:42
Then we have the cardiothoracic muscles, and they go from the cranium to the thorax.
0:47
So, these are the groups we’re going to focus on n this video.
0:50
We’re gonna cover the origin, insertion, and function of these muscles.
Division of Facial Muscles
0:54
We’ll start with the deep muscles of the neck.
0:56
So, the deep muscles of the neck are the Longus Capitis, Longus Colli, Rectus Capitis Anterior
1:03
and rectus capitis Lateralis.
1:04
Let’s now add a skeleton for the outline and start with the Longus Capitis.
1:09
The longus capitis is this tiny muscle located in the anterior side of the vertebrae.
1:15
So if we remove the mandible and the teeth, and look at the muscle from this perspective,
1:19
we’ll be able to see it better.
1:22
So the Longus Capitis originates from the transverse processes of vertebra C3 to C6,
1:27
and it inserts at the inferior surface of the basilar part of the occipital bone.
Deep Muscles of the Neck
1:32
Primarily, when both sides contract, they ventrally flexes the head, but when one side
1:38
contracts, it turns the head to the side.
1:40
Next, we have the Longus Colli, which is a large muscle you see here.
1:45
Longus Coli consist of three parts.
1:48
One is the superior oblique part, which is up here.
1:51
Then there’s the vertical part, which is here in the middle, and then there’s the
1:54
inferior oblique part, which is here So, the Superior oblique part of the Longus
2:00
Colli, originates from the Transverse processes of Vertebra C3-C5, and it inserts at the anterior
2:07
tubercle of Atlas, as you see here.
2:10
The Vertical part originates from the body of C5-T3, which are all of these.
2:15
And it inserts at the Body of C2-C4, here.
2:20
The Inferior Oblique Part originates from the Body of T1-T3, down here.
2:25
And it inserts at the transverse process of C5-C6.
2:30
And the function of this muscle is the same as longus Capitis.
2:34
Bilateral contraction flexes the neck.
2:36
Unilateral contraction turns the cervical vertebral column to the side.
2:40
Then we have the Rectus Capitis Anterior.
2:43
This is a tiny muscle located just underneath the skull.
2:47
It originates from the Lateral mass of atlas, which is C1.
2:51
And it inserts at the Basilar part of the Occipital Bone.
2:54
So again unilateral contraction causes lateroflexion of the head, bilateral contraction causes
3:00
ventral flexion of the head.
3:02
Then we have the Rectus Capitis Lateralis, which is also a tiny muscle.
3:07
It originates from the Transverse process of Atlas C1, and inserts at the lateral part
3:12
of the occipital bone.
3:14
And the function is primarily lateral flexion of the head.
3:17
So that was all the Deep muscles of the Neck.
3:20
Now let’s talk about the lateral muscles of the neck.
Lateral Muscles of the Neck
3:23
And these are mostly the Scalenus muscles.
3:26
We have a Scalenus Anterior, Medius and Posterior.
3:30
And they primarily originate from the first and second rib, so let’s remove the clavicle
3:35
to see them better.
3:36
The Scalenus Anterior is highlighted here.
3:39
It originates from the Transverse process of C3-C6, as you see here. and inserts at
3:45
the Scalenus tubercle on the 1st rib.
3:48
Then the scalenus medius is located just posterior to the scalenus anterior.
3:53
And this one originates from the C1-C7 or C2-C7, it varies depending on the source you’re
4:00
studying from, but one thing they can all agree on is that it inserts on the surface
4:05
of the 1st rib, behind the scalenus anterior.
4:08
The Scalenus Posterior however is located posteriorly to the scalenus Medius, and it
4:14
originates from the transverse process of the C5-C6 vertebra and inserts at the surface
4:20
of the 2nd Rib.
4:22
Awesome.
4:23
So those are the lateral muscles of the neck.
4:25
Scalenus Anterior, Scalenus Medius and Scalenus Posterior.
4:29
Now between the Scalenus Anterior, and scalenus Posterior, you’ll find a large artery passing
4:34
between them called the subclavian artery, as it becomes the axillary artery when it
4:39
passes them.
4:40
So that was these.
Suprahyoid Muscles
4:42
Now let’s add the hyoid bone and cover the suprahyoid muscles, which are the muscles
4:47
located above the hyoid bone.
4:49
And they are the Digastricus, Stylohyoid, Mylohyoid and Geniohyoid muscles.
4:53
And again, they’re above the hyoid bone.
4:56
So, let’s change the angle a little bit.
4:59
Now these muscles are primarily either going to attach to the inner surface of the mandible,
5:05
or temporal bone, and from there, they’ll attach to the hyoid bone.
5:09
And all of them have a common function, that is to fixate the hyoid bone in place by pulling
5:15
on it from all sides.
5:16
Ok.
5:17
So the digastricus muscle is here.
5:19
It consists of two parts.
5:20
There’s a Posterior Belly, behind the hyoid bone.
5:23
And an anterior belly, which is in front of the hyoid bone.
5:27
Now the Posterior belly will originate from the mastoid notch of the temporal bone, and
5:32
then it’s going to insert at the tendon that inserts at the hyoid bone.
5:36
The Anterior belly will originate from the tendon that inserts at the hyoid bone, and
5:41
insert at the digastric fossa of the mandible.
5:45
And the main function of this muscle is to pull on the hyoid bone to keep it in place.
5:50
Next we have the stylohyoid muscle, which is here.
5:52
It originates from the styloid process of the Temporal Bone, and then insert at the
5:57
Hyoid bone.
5:58
And again, pulls on the hyoid bone, to keep it in place.
6:01
Next is the Mylohyoid Bone, which is this one.
6:04
Originates from the mylohyoid line of the Mandible and insert at the hyoid bone.
6:10
Then we have the Geniohyoid muscle, which is located back here, just on top of the mylohyoid
6:14
muscle.
6:15
It originates from the mental spine of the mandible and insert at the hyoid bone.
6:20
So that was the suprahyoid muscles.
Infrahyoid Muscles
6:23
Next let’s covert he infrahyoid muscles.
6:26
And these include the Sternohyoid, Sternothyroid, Thyrohyoid and Omohyoid muscles.
6:33
So again, remember that these are located underneath the hyoid bone, but some of these
6:37
muscles have the word ‘’Thyro’’ in it, meaning that they’ll be attaching to
6:41
the Thyroid Cartilage as well, so let’s add the Larynx, and the Trachea.
6:46
So first we have the Sternohyoid muscle, which is here.
6:50
The Sternohyoid muscle originate from the sternum and the clavicle, and it’s going
6:54
to insert at the hyoid bone.
6:57
And this one is also going to pull on the hyoid bone to fixate it.
7:01
Next, we have the Sternothyroid muscle, which is located here, just behind the sternohyoid.
7:06
This one will originate from the Sternum and the Clavicle as well, but insert at the Thyroid
7:12
Cartilage.
7:13
And it pulls the Thyroid cartilage downwards.
7:15
Then there’s the thyrohyoid muscle, which is located here.
7:19
It originates from the thyroid cartilage, and then insert at the hyoid bone to fixate
7:23
it as well.
7:25
The last one is the Omohyoid Muscle.
7:28
This is a long muscle that actually connect the Scapula to the hyoid bone.
7:32
And in the middle, there’s a Tendinous Intersection that divides the Omohyoid muscle into a superior
7:38
belly, and an inferior belly.
7:40
So again it’s going to originate from the scapula, and then through the tendinous intersection
7:45
it’s going to insert at the hyoid bone to depress the hyoid bone.
7:50
It might also assist with elevation of the scapula in some occasions.
7:53
Primarily.
7:54
Um, the tendinous intersection is also attached to the carotid sheath, meaning it can also
8:00
pull on the carotid sheath to dilate the internal jugular vein.
8:04
So that was the infrahyoid muscles.
Craniothoracal
8:07
Now let’s cover the craniothoracal muscles.
8:10
And these include the Sternocleidomastoideus, Trapezius and the Platysma.
8:14
Alright.
8:15
Let’s do the Sternocleidomastoideus first.
8:18
These are large muscles located on either side of the neck.
8:22
They Originate from the Sternum and the Clavicle, and then they go up and insert at the mastoid
8:28
process, as well as the superior nuchal line.
8:30
And it has several functions.
8:33
Unilateral contraction will lateral flex the head and then rotate the head to the opposite
8:38
side.
8:39
Bilateral contraction of the anterior fibers will ventrally flex the head.
8:44
Bilateral contraction of the posterior fibers will dorsiflex the head.
8:48
So that is the Sternocleidomastoideus.
8:51
Next we have the Trapezius.
8:53
Now the trapezius is also considered as a muscle of the back, keep that in mind.
8:57
It all depends on what source you’re studying from.
9:00
But all in all it’s also a craniothoracal muscle.
9:03
Now the Trapezius consists of 3 parts.
9:05
There’s a Superior Part, a Middle part and an inferior part.
9:10
The superior part will originate fro the Superior nuchal line, the external occipital protuberance,
9:16
and the nuchal ligament.
9:18
It’s then going to insert at the Acromial end of the clavicle, as you see here, as well
9:23
as the acromion of the scapula.
9:25
Then we have the middle part, which originates from the spinous process of the C7-T3 or T4,
9:31
and it’s going to insert at the Spine of the Scapula as you see here, and the acromion.
9:36
Then we have the Inferior Part, which originates from the spinous process of T4-T12 and insert
9:42
at the spine of scapula as well.
9:45
Ok.
9:46
So what is the function of the Trapezius?
9:48
The Inferior part will pull the shoulder downwards, Middle and superior fibers will pull the scapula
9:55
towards the midline, as well as elevating the scapula.
9:58
They may also extend the head to the side as well in strong contraction.
10:02
But primarily, they’re associated with movement of the scapula.
10:05
So that is the Trapezius.
10:08
The last muscle is the Platysma.
10:10
And the platysma is located veery superficially on the anterior region of the neck, and it
10:16
covers all the neck muscles.
10:17
It originates from the pectoral and deltoid fascia, down here, and insert at the base
10:23
of mandible, lower lip, and the skin around the mouth.
10:27
And its function is primarily controlling the tension in the skin of the neck.
10:32
And you’ll often see it protruding as fibers on the neck when you tense it.
10:36
It can also depress the angle of the mouth and the mandible.
10:40
So that was all the muscles of the neck that I wanted to talk about.
10:43
And I hope that was helpful.