Description

This video covers the Division of Facial Muscles, their origins, insertions, and functions.

Division of Facial Muscles

• Muscles of the Scalp
• Muscles around the Eye Opening
• Muscles around the Oral Opening
• Muscles of the Nasal Opening
• Muscles around the Ear Opening
• All insert into the skin
• All are innervated by the facial nerve
• All originate from the 2nd Pharyngeal Arch during development

Muscles of the Scalp

Occipitofrontal Muscle (Musculus Occipitofrontalis)

• Occipital Belly (Venter Occipitalis)
  • Origin: Highest Nuchal Line (Linea Nuchalis Superior)
  • Insertion: Epicranial Aponeurosis (Galea Aponeurosis)
• Frontal Belly (Venter Frontalis)
  • Origin: Epicranial Aponeurosis (Galea Aponeurosis)
  • Insertion: Skin of Eyebrows

Muscles around the Eye Opening

Orbicularis Oculi (Musculus Orbicularis Oculi)

• Orbital Part
  • Origin/Insertion: Medial Palpebral Ligament
• Palpebral Part
  • Origin: Medial Palpebral Ligament
  • Insertion: Lateral Palpebral Ligament
• Lacrimal Part
  • Origin: Lacrimal Bone
  • Insertion: Lacrimal Sac

Procerus (Musculus Procerus)

• Origin: Bridge of Nose
• Insertion: Skin of Forehead

Corrugator Supercilii (Musculus Corrugator Supercilii)

• Origin: Glabella, Supraorbital Margin
• Insertion: Skin of Eyebrow

Muscles around the Oral Opening

Sides (“Smile”)

• Zygomaticus Major (Musculus Zygomaticus Major)
  • Origin: Zygomatic Bone
• Zygomaticus Minor (Musculus Zygomaticus Minor)
  • Origin: Zygomatic Bone
• Risorius (Musculus Risorius)
  • Origin: Masseteric Fascia
  • Insertion: Skin at the Angle of the Mouth

Angle of the Mouth

• Levator Anguli Oris (Musculus Levator Anguli Oris)
  • Origin: Anterior Surface of Maxilla
  • Insertion: Skin at the Angle of the Mouth
• Levator Labii Superioris (Musculus Levator Labii Superioris)
  • Origin: Infraorbital Margin of the Maxilla
  • Insertion: Skin of the Upper Lip

Depresses the Angle of the Mouth

• Depressor Anguli Oris (Musculus Depressor Anguli Oris)
• Depressor Labii Inferioris (Musculus Depressor Labii Inferiores)

Lateral Wall of the Oral Cavity (“Satisfaction”)

Buccinator (Musculus Buccinator)

• Origin: Alveolar Processes of Maxilla and Mandibula, Pterygomandibular Raphe
• Insertion: Skin at the Angle of the Mouth

Lips (“Kissing Muscle”)

Orbicularis Oris (Musculus Orbicularis Oris)

• Marginal Part
• Labial Part

Chin (“Muscle of Doubt”)

Mentalis (Musculus Mentalis)

• Origin: Alveolar Processes of Mandibula
• Insertion: Skin of the Chin

Muscles of the Nasal Opening

Nasalis (Musculus Nasalis)

• Transverse Part: Origin: Anterior Surface of Maxilla, Insertion: Dorsal Cartilage of the Nose
• Alar Part: Origin: Anterior Surface of Maxilla, Insertion: Dorsal Cartilage of the Nose

Levator Labii Superioris Alaeque Nasi (Musculus Levator Labii Superioris Alaeque Nasi)

• Origin: Frontal Process of Maxilla
• Insertion: Skin of the Upper Lip, Skin of the Nasal Wing

Muscles around the Ear Opening

Extrinsic Muscles of the Ear

• Auricularis Anterior: Origin: Temporal Fascia, Insertion: Auricle
• Auricularis Superior: Origin: Epicranial Aponeurosis, Insertion: Auricle
• Auricularis Posterior: Origin: Temporal Bone, Insertion: Auricle

Transcript

Introduction
0:03
What’s up. Meditay here and in this video, we’re gonna cover all the muscles
0:07
of facial expression. Which are a part of the muscles of the head. Alright so
0:12
All muscles of the head are divided into two groups. The first group is the muscles
0:16
of mastication. Mastication means to chew, so those are the muscles responsible for chewing
0:21
when you’re eating. And the second group are gonna be fascial muscles or the muscles that
0:26
are gonna be responsible for facial expression. So we’re gonna focus of the mastication muscles here.
0:29
So in this video, we’re gonna cover the origin and insertion points of all the muscles you’ll
0:34
find in the facial region. In my previous video, we looked at the muscles of mastication,
0:39
if you’re unfamiliar with the mastication muscles, I highly recommend you to watch
0:43
that one first as it helps you to gain the full picture of the muscles you’ll find in the head.
Division of Facial Muscles
0:48
Alright. So the muscles of facial expression can be divided into groups depending on
0:53
the anatomical location. We’re gonna have 1 muscle in the scalp, 3 around the eye opening,
0:59
10 around the oral opening, 2 around the nasal opening and 3 around the ear opening.
1:05
And so all of these muscles have a few things in common.
1:08
And the first one is that all of the muscles of facial expression insert at the skin, and they
1:14
produce wrinckles n the skin once they contract. Another ting they have in common is that all
1:19
of them are innervated by the facial nerve, which is cranial nerve number 7.
1:24
The last thing is that they all come from the 2nd pharyngeal arch during development.
1:29
So now that we kinda have a general overview of the muscles, let’s start with the muscles
Muscles of the Scalp
1:34
of the scalp, which is the occipitofrontal Muscle. This is a flat muscle located on top of the scalp.
1:41
It consists of an Occipital Belly, which originates from the highest nuchal line
1:45
on the occipital bone. And it inserts at the Epicranial Aponeurosis, or Galea Aponeurosis.
1:52
Then more anteriorly, you’ll find the Frontal Belly, which originates
1:56
from the Epicranial Aponeurosis, and insert at the skin of the eyebrow.
2:01
The function of this is to pull the skin of the forehead up,
2:05
forming horizontal lines on the forehead, as you see here. The occipital bellys main function is
2:10
really stabilizing the aponeurosis and tensing it. Next we have the muscles around the eye opening.
Muscles around the Orbital Opening
2:16
And these include the Orbicularis Oculi, Procerus and the Corrugator Supercilli.
2:22
The orbicularis oculi is a circular muscle, as you see here, consisting of three parts. These
2:29
are the orbital part, which is the peripheral part of the muscle going around the eyes.
2:34
The palpebral part that covers the eyelids, and a lacrimal part for the lacrimal sac.
2:39
So the orbital part, is this one. It originates from the medial palpebral ligament,
2:45
then goes around the whole eye in a loop and then inserts at the medial palpebral ligament
2:50
again. The medial palpebral ligament is a small ligament located on the medial end of the eyelids.
2:57
The palpebral part again is the part that covers the eyelids.
3:01
They originate from the medial palpebral ligament, and insert at the lateral palpebral ligament.
3:07
And here just to visualize it. Here si the medial palpebral ligament,
3:10
and here is the lateral palpebral ligament. So the Palpebral part of the muscle goes like this.
3:16
The function of these two parts is to firmly close the eye lids, and creating wrinkles extending
3:22
outwards from the lateral angle of the eye as you see here. The lacrimal part, originates from the
3:28
lacrimal bone and insert at the lacrimal sac. And it’s located in this region. What it does
3:35
is that it dilates the lacrimal sac, which aids the drainage of tears from the eyes, down through
3:41
the nasolacrimal duct and then down to the nasal cavity. So tears are produced by the lacrimal sac,
3:49
and this muscle really just opens up this lacrimal sac so that the excess tears can flow down into
3:54
the nose. So that is the orbicularis oculi Next we have Procerus muscle.
4:00
And the procerus muscle si located between the eyebrows as you see here. It originates from the
4:06
bridge of the nose and inserts at the skin of the forehead, forming a horizontal wrinkle on
4:11
the root of the nose as you see here. Alright. And the last one is the Corrugator Supercilii,
4:17
which are located here, in the eyebrows. This muscle orginiates from the glabella and the
4:22
supraorbital margin. And it inserts at the skin of the eyebrow. And when this muscle contracts,
4:28
it pulls the eyebrows medially and inferiorly and forms vertical wrinkles above the root of
4:34
the nose, forming facial expressions of frowning and pain as you see here.
4:39
So that is the muscles around the eye opening. Next we have the muscles around the Oral Opening.
Muscles around the Oral Opening
4:45
And these are 10 muscles divided into 5 groups based on the facial expression they produce when
4:51
they contract. The first group are the muscles on the side of the mouth that produces a smile!
4:56
All of these muscles have a common insertion point, but different origin points.
5:00
These are the zygomaticus major, which is this one. It originates from the Zygomatic bone as
5:06
you see here. Then we have the zygomaticus Minor, which is this one. It also originates
5:11
from the zygomatic bone, but more anteriorly. Then we have Risorius muscle, which is this one,
5:17
originating from the masseteric fascia. So remember we had the masseter muscle,
5:21
for mastication? On top of the masseter muscle, there’s a fascia called masseteric fascia,
5:27
which is connective tissue forming a smooth surface around the muscle for less friction.
5:33
This muscle originates at this fasica. And all fo these three muscles insert at the
5:38
Skin of the angle of the mouth. To produce a beautiful Smile!
5:42
Next we have the muscles that either depresses the angle of the mouth,
5:46
or lifts the angle of the mouth. The muscles that lift up the angle fo the mouth
5:50
are the Levator anguli oris, which is this one, and the levator labi superiors, which is this one.
5:57
The Levator anguli oris originates from the anterior surface of the maxilla
6:02
and it inserts at the skin of the angle of the mouth. The levator labii superioris originates
6:07
from the infraorbital margin, of the maxilla, and it inserts at the skin of the angle of the mouth.
6:13
And they both lift the angle of the mouth. The muscles that depresses the angle of the mouth
6:18
are the depressor anguli oris which is this one, and the depressor labii inferioris, which is this
6:24
one. They both originate from the base of the mandible, down here. The depressor anguli oris
6:30
inserts at the skin of the angle of the mouth, but the Depressor labii inferioris inserts at the skin
6:36
fo the lower lip. These muscles make a sadface. But the depressor labii inferioris depresses the
6:42
lower lip, and pulls the lower lip laterally, which produces an expression that look a lot
6:47
like contempt. Alright. So these are the muscles that act on the angle fo the mouth.
6:52
Next we have a muscle located on the lateral wall of the oral cavity, called the Buccinator Muscle.
6:58
Which is located here. This muscle originates from the alveolar processes of the maxilla and
7:03
mandibula, as well as the pterygomandibular raphe, located back here. And they insert at
7:09
the skin of the ange of the mouth. And when this muscle contracts, it pulls the angle of
7:14
the mouth laterally, forming a facial expression of satisfaction as you see here. So that is the
7:20
buccinator. Next we have the kissing muscles, around the oral opening, which is here. This
7:26
muscle si called musculus orbicularis oris, and it consists of a marginal part which is the outer
7:32
fibers, and a Labial part which give the shape of the lips located here. These muscle fibers
7:39
are arranged circularly underneath the skin, and they protrude the mouth forming a kissing face.
7:45
The last group is the muscle of doubt, located in the skin. And it consists of the Mentalis Muscle.
7:49
It originates from the alveolar process of the mandibula,
7:53
and insert at the skin of the chin, and when these muscle fibers contract,
7:57
they pull the skin upwards, producing a facial expression of doubt .. kind of, as you see here.
8:03
So that was all the muscles around the oral opening.
Muscles of the Nasal Opening
8:07
Then we have the muscles around the nasal opening. So if we add the actual cartilages of the nose.
8:12
The muscles around the nose acts directly on the nose itself. The first one is the Nasalis Muscle,
8:18
which consist of two parts according to the course of its fibers: These are the transverse
8:24
part (also called the compressor naris) and the alar part (also called dilatator naris).
8:30
They both originate from the anterior surface of the maxilla, and they both insert at the dorsal
8:36
cartilage of the nose. The alar part inserts a little more anteriorly than the transverse part.
8:41
The transverse part constricts the nostrils and the alar part dilates them. As you see here.
8:46
So that is the Nasalis Muscle. The other muscle is called Levator labii
8:51
superioris alaque nasi. This muscle originates from the Frontal process of the maxilla, and
8:57
insert at the skin of the upper lip and the skin of the nasal wing. And when they contract, they
9:03
upp the lips and nasal wing in this direction, which dilates the nostrils, elevates the upper
9:09
lip and produces an expression of discontent Alrgiht. So finally, let’s do the muscles
Muscles around the Ear Opening
9:15
around the ear opening, which are three. And they look like this.
9:18
These three muscles are called the extrinsic muscles of the external ear. And these are the
9:24
auricularis anterior, auricularis superior and the auricularis posterior! All of these muscles insert
9:30
on the root of the auricle. The Auricularis anterior originate from the Temporal Fascia,
9:36
which is the fascia covering the temporal muscle. Auricularis superior originate from
9:41
the Epicranial Aponeurosis, and the auricularis posterior originate from the Temporal bone.
9:47
Their common function is movement of the auricle. To each direction as you see here. They really
9:53
have no practical importance in humans. But they’re more important in animals that are
9:58
dependent on their hearing, like your typical dog that that are able t move his ear around.
10:03
In these animals these three muscles are more developed than in humans.
10:07
So that was all the muscles of facial expression and I hope this was helpful.