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#8
ANATOMY
MUSCLES OF THE
HEAD
Nermeen Sweiti &
Sua'dad Al-Ani
8/10/2015
Nabeel Khouri
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Today we will start a new topic: MUSCLES
o
a.
b.
c.
How should we study the muscles:
Tables (I will add them in the sheet).
Figures from the atlas or google.
Study them as group (muscles of the head, neck, facial,…etc)
 terminology ( just read them and try to memories them ) :
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 These two tables summarize , the terminology of the muscles, this
terminology is mainly Latin and it was put by great anatomists back then
and passed to us.
 Pay good attention to the terminology, for it serves you good in
studying, memorizing and understanding them, these names reflect their
locations by including the bones and parts of the body which they cover,
also their actions. it will make identifying structures easier for you in the
lab as well.

For example: When we say Abdominis means (abdominal) , Anconeus
(elbow joint) , Auricularis (auricle of ear) , Brachialis (brachium this is
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the arm). Examples for the action : (Adductor , Abductor , Depressor ,
Extensor , Flexor , Levator , …. Etc. )
Conclusively, the name of the muscle usually consists of two parts, one
describes its action –functional name- and the other describes its
location.
for example :
a. Adductor Magnus.
b. Adductor Medius.
c. Adductor Minimus.
They are located within the region of the medial aspect of the thigh , but
Adductor Policis for is in the forearm.
We won’t be able to explain the action and origin of all the muscles, because
this might take more 20 lectures, and some are too obvious to be explained.
Muscle of the facial expression
 These are the muscle that change the expression of the face; they originate
partially from the bone and mainly from the skin, and insert into the skin of
the face , that’s why they will produce modification of the shape or the
figure of the face.
 These muscles are arranged in different structures or shapes, they could be
sphincters, dilators, elevators or depressors.
 These muscles are the most anterior, extending from the occipitofrontalis
muscle to the hyoid bone.
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 The nomenclature of these muscles will depend on their function, shape or
location.
 For example, Depressor Labii inferioris:
Its function
lip
location
 This muscle arises from the oblique line of the mandible, there at its
origin its fused with the fibers of the Platysma muscle (located in the
neck) and inserts on the skin of the inferior lip when its contracted it
will depresses it.
 Orbicularis Oculi and Orbicularis Oris they are circular in shape and they
surround an opening and their function is closing it; they will help in
closing the eye and mouth respectively.
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 This muscle originates from a raphe, called the median raphe1, this
raphe is attached to maxilla, nasal and frontal bone, in conclusion it
originates from the median wall of the orbit. This muscle covers the
superior and the inferior parts of the eye, therefore helps in closing it
 Orbicularis Oris this has two raphes; one on the left and one on the
right, these raphes are a point of origin of other muscles that act on the
mouth , such as Depressor Angulii Oralis.
 Depressor Angulii Oralis and levator Angulii Oralis
They act on the lateral angles of the mouth, and the superiors lip, respectively.
 Because the angle of the mouth is deep, this deepened structure like when
you look at the face you will see that there is a depression in the lateral
aspect of the mouth >> this depression is because of this
Angle= Angulii
structure that is made of tendons (raphe tendons) that is
Oralis = mouth
located in the left and right aspects of the mouth angle, we
have one is depressor and one is levator of the Angulii Oralis.
 Zygomaticus major and Zygomaticus minor
They originate from the zygomatic bone.
they will go to the substances of the Superior Labii (Lip) and those are
elevators; they draw the angles of mouth superiorly and laterally.
 Levator Labi Superioris and Depressor Labi Inferioris.
1
the Dr. pronounced it as the “ralph” but raphe is the correct word.
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 Levatory Labii Superioris Alaeque Nasi of the nose, is another
elevator of the ala of the nose (some people might move their nose upward and
backward).
“This muscle is attached to the upper frontal process of the maxilla and
inserts into the skin of the lateral part of the nostril and upper lip.”wiki
mnemonic to remember its name is, "Little Ladies Snore All Night."
 Corrugator supercilli, which is also considered one of the facial
expression muscles.
“The corrugator draws the eyebrow downward and medially, producing the
vertical wrinkles of the forehead. It is the "frowning" muscle” wiki
 Procerus, a very small muscle located in between the eyes, this muscle
together with the corrugator they will elevate the piece of nose upward.
**Zygomaticus major and
Zygomaticus minor, we consider
them the only muscles of the facial
expression muscles which originate
from bones the other ones don’t.
**this point is debatable **
All the facial expression muscles
practically act on something either
they will act on the nose, eye, lips or
mouth, most of those have different
action but they have mainly similar
origin and insertion they will go
from the skin.
 Platysma muscle
This muscle contributes in facial expression (draws outer part of the lip
inferiorly) , depresses the chin –with the mentalis- and might be
considered a respiratory muscle!
It is a very thin muscle embedded within the fascia of the skin, if you
dissect it you will be able to see that it has just bands of skeletal muscles
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diversified here and there, these bands will help in facial expresser
muscle.
This muscle goes all the way up and sometimes reaches the structure that
covers this Masseter muscle and the Buccinators muscle, so it will go all the
way passing the inferior border of the mandible and go within the face and
blend with the other muscles such as the facial expresser muscle and as well
as the Masticatory muscle.
** These are the
muscles of facial
expresser.
 Fronto Occipitalis1 (one of the facial expresser muscle) it is a
continuous muscle, it has two bellies that are connected with the Gala
Aponeurotica.
If you look at the gala aponeurotica (epicranial aponeurosis) this muscle
practically begins from it, and blends with the Orbicularis Oculi and begins
from the upper part of the brows regions and going all the way back into the
1
commonly known as occipitofrontalis.
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Occipitalis and insert in the skin and originated in the skin, and that will move
the skull of the head backward and upward by contraction.
Facial expression muscles, are very important for those who are concerned about their beauty
and having a perfect wrinkleless face :P females mostly.
usually in the midline there is a fusion of those muscles and there is an aponeurosis, this
muscle(platysma) practically make the wrinkles on the forehead , so to get rid of these wrinkles
you have to paralyze the muscle and when you want to paralyze the muscle you put Botox over
there.
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1) All these muscle are innervated by the facial nerve.
2) They are very important clinically for the facial paralysis. ( when we do
paralysis by Botox we do it for the fiber not the nerve)
3) Facial palsy is one of the diseases that is common, this facial palsy
usually occurs at the peripheral aspect of the nerve within the parotid
gland because the nerve goes through the parotid gland.
 One half of the facial expression muscles will be paralyzed partially,
(all of them, the ones which elevate and depress) , it will result in:
a. Open eye, it will not close so we will have lacrimation.
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b. Open mouth with the angel depressed down and that we will
have salivation. It will affect the ability if talking and
pronouncing words properly.
 The second group of muscles are: muscles of mastication.
 Those muscles from their name they will help in the masticatory
action, *the chewing muscles*
 They are two muscles, the most important one is the masseter
muscle (which is the most powerful in the human being, The power
of the muscle is almost 25 kg)
 There is also temporalis, lateral and medial pterygoid muscle and the
buccinators muscle.
 Buccinators muscle is considered as both :
1- Masticatory muscle
2- Partially, facial expression muscle
But we will consider it as masticatory muscle (buccinators), because buccinators
muscle going into skin and it will coming from anterior border of mandible (ramus).
 Now, this muscle will allow the bollus of the food to go from one
side to another, and this muscle again will allow the cheeks and face
to be inflated.
Persistent use of the buccinators and the masseters, will cause them hypertrophy; they
will be bigger. After that if this use is reduced significantly, they will get very weak, and
go downward, causing what is called a bulldog face .
This happens for people who play an instrument like the saxophone, and stop playing it,
after few years their hypertrophied muscles will weaken.
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Origin : Alveolar process of maxilla and mandible and pteromandibularraphe
Insertion : Fiber of OrbicularisOris
Innervation :Facia lNerve (VII)
Action : draws the angle of the mouth laterally and superiorly ( also the book
says… Presses cheeks against teeth)
source: pulse’s made easy, the Dr didn’t mention these.
 Temporalis muscle it originate from the entire temporal lines in the
squamous part of the temporal fossa therefore, it has two origins (one
from superior and inferior temporal line) . it's Diverging Fibers go
and form tendons, this tendons go into the coronoid process of the
mandible it will elevate the mandible and retract it backwards (and
those are two actions of the temporalis muscle, it is very big muscle).
** this is the end of my part, I hope you find it easy to study 
** if these is any mistake please right in the correction zone .
Your college Nermeen Sweiti ^^
 The masseter:
The masseter muscle originates from
the zygomatic arch, goes all the way
down into the angle of the mandible
and the posterior border of the
mandibular rami, and a small part of
the inferior border of the body of the
mandible.
(So it’s a very important elevator of
the mandible inferiorly)
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*There are two other
muscles considered to be
masticatory muscles, they
are deep to the temporalis;
The Lateral Pterygoid
muscle, and the Medial
Pterygoid.
 The Lateral Pterygoid
It has an upper head and a lower head, it is a very important muscle because it
originates from the lateral pterygoid plate and inserts into the part that goes
into the capsule of the Temporomandibular joint ,so it blends with the capsule
of the temporomandibular joint (TMJ) and this blending will give stability to
this joint. In addition to that it will protrude the mandible forward, so
practically this is very important muscle and a very strong muscle.
 The Medial pterygoid muscle
It has two heads; a superficial and a deep one. It originates from the medial
surface of the lateral portion of the pterygoid plate, and inserts into the inferior
aspect of the medial surface of the mandiblular ramus. They will have to
elevate and protrude the mandible, so they have two actions : (elevation and
protrusion) and those are the muscles of mastication.
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A summary of the masticatory muscles.
Muscles Of The Tongue
They are two types:
 Intrinsic muscles
 Extrinsic muscle
1) The Intrinsic muscles : from their name ,those are muscles that run from
a part of the tongue to another, their action is to change the shape of the
tongue and they don't originate from a bone, instead they originate and
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insert within the substance of the tongue. They are of three types:
 Oblique; will change the shape in a transverse way together with the
transversalis.
 Transverse; runs from one side to another.
 longitudinal, runs along the side of the tongue, it will roll up the tongue
backwards and so on.
2) The extrinsic muscles:
These muscles originate from the bone and insert into the tongue, and those
will move the entire tongue in various directions; such as anteriorly,
posteriorly, and laterally, they also will protrude and retract the tongue.
So the extrinsic muscles together with the intrinsic, they will manage the
function of the tongue, like rolling and extending along with shape altering.
The extrinsic muscles are:
 Genioglossus muscle : originates from the posterior aspect of the
mandible, specifically from the Geniohyoid line which is in medial aspect
of the mandible.
Genio: mandible
 Hyoglossus: originates from the hyoid bone and inserts
into the side of the tongue .
Glossus: tongue
 Styloglossus: originates from the styloid process and inserts into the
tongue.
Those three muscles are very important; 1 they move food around the mouth,
2
along with the buccinator, they hold the food while teeth are grinding and
they 3push the food up toward the palate so it can be swallowed, 4change the
shape and modify the sound during speech altogether with the intrinsic
muscles.
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Summary of tongue muscles:
Muscles of the pharynx:
If we go deeper within the aspect of the neck we will find the pharyngeal
muscles:
1) Pharyngeal constrictor muscles, they are superior, middle and inferior
pharyngeal constrictors, they are very important in holding the food and
pushing the bolus of food downward. They originate from different parts
like the hyoid, the mandible and the substance of the larynx. They insert
into a tent shaped raphe; which is the raphe aponeurosis; the constrictor
muscles aponeurosis, located in the posterior aspect from the pharyngeal
and continues down with the esophagus.
2) Laryngeal elevator muscles
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3) Palatal muscles
- Tensor veli palatini
- Levatory veli palatini
These practically occur in the posterior aspect of the mouth in the oropharynx
and they will elevate the palate and depress it, as well as they will put the
palate in tension.
* the Palate made of two parts ===> hard and soft palate which is the roof of
the tongue, this part of palate ,which is the posterior aspect is made of these
muscles (palatal muscles).
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Muscles of the neck :
They can be divided into two parts :
1) Muscles that are superior to the hyoid bone ===> suprahyoid
2) Muscles that are inferior to the hyoid bone ===> infrahyoid
**most of these muscles will take their names from the part that they originate
from and they will insert into the hyoid bone mainly except the (digastric
muscle that have a different name) .
 The suprahyoid muscles: elevate the hyoid bone, they help in
swallowing and speaking.
1) Mylohyoid muscle : extends from the mandible; the inferior border to one
third to the hyoid bone.
2) Stylohyoid muscle : goes from the styloid process into the hyoid bone
3) Digastric muscle : has 2 bellies ,anterior and posterior belly.
The Anterior belly comes from the mandible; from the posterior edge
of the lower border of the mandible, specially in the midline and it goes all the
way into the hyoid bone.
The Posterior belly from the mastoid of the temporal bone, to the hyoid
bone.
**this muscle has a raphe or belly of fixation on the hyoid bone ,it will be
fixed in the hyoid bone by aponeurosis gate and this gate allows this tendon to
continue backwards ,superiorly and became again another part of this
digastric ,which is the posterior belly. So the two belly are made of muscles
and the connection between the two bellies is a tendon ,this tendon goes into a
raphe and this raphe is surrounded by the stylohyoid aponeurosis.
☆ Stylohyoid aponeurosis will help in forming a tunnel for this tendon to
allow passage from one belly to another, they both insert into this raphe
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and this raphe goes into providing insertion for the stylohyoid muscle.
 The infrahyoid muscles: they divide the neck into two
triangles ,specially the (sternocleidomastoid).
**these two triangles practically are very important clinically to locate and
determine the organs, the arteries and the structures that belong to the neck.
**These muscles are named for their position inferior to the hyoid bone.
1) The omohyoid: originates from suprascapular notch, to the body of
hyoid
2) The sternohyoid: originates from the sternum to the body of the hyoid.
3) The thyrohyoid: originates from the thyroid cartilage to the hyoid bone.
So these muscles, they come from the sternum or the clavicle all way to the
inferior aspect of the hyoid bone; the cornio of the hyoid bone.
so these are the muscles that are located within the midline and they cover
most of the deepest part or the middle part of the anterior triangle
of the neck.
 The sternocleidomastoid:
Sternocelido >> the sternum and the clavicle>> the origins of this muscle
Mastoid>> its insertion; the Mastoid process of temporal bone.
It has 2 heads, one from sternum ,one from the clavicle and then go to the
mastoid. It's a very powerful muscle that; both heads contract in both sides;
left and right.
Right side: rotation to left & lateral flexion to right
Left side: rotation to right & lateral flexion to left
Both sides: extension of head at atlantooccipital joint & flexion of
side will rotate the head into the lateral sides and also contraction.
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The respiratory muscles:
We have two types of respiratory muscles, primary and accessory; the
primary are:
- The diaphragm
The accessory:
- Intercostal muscles
- Scalenus anterior and scalenus medial muscles
 Scalenus anterior and scalenus medial
**They are located in the neck , they will go to the first rib and they are deep
within the posterior triangle of the neck and deeper to the sternocleidomastoid,
so they are covered by the sternocleidomastoid.
**They have a gab between them; Scalenus triangle or scalenus gab it allows
the brachial plexus to pass from the neck to the upper extremities.
Origin and Insertion:
The scalenus anterior and medius have a wide origin at the transverse
processes of the cervical vertebra.
Scalenus Anterior : It arises from the anterior tubercles of the transverse
processes of the third, fourth, fifth, and sixth cervical vertebrae.
Scalenus medial: arises from the posterior tubercles of the transverse
processes of the lower six cervical vertebrae.
most of the transverse processes of the cervical vertebrae provide insertion
for those muscles because they need power for elevating the first rib upward
in order to increase the size of the thoracic cavity , and they insert on the
upper surface of the 1st rib. There are ridges over the superior surface of the
first rib, two ridges ---> one for the anterior scalene and one for the medial
scalene.
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The posterior scalene, the third muscle in that group, it doesn't reach the first
rib so it's not one of the respiratory muscles.
Deeper muscles of the neck:
they are in the anterior aspect of the neck and have nothing to do with the
respiration but the Dr. thought that we should know them :* they are deeper to
the respiratory ones and deeper to the pharynx*
- Longus colli muscle
- The longus capities muscle
you can see them only from the anterior aspect of the neck ,immediately
anterior to the body of the cervical rib.
 The primary muscles of the respiration :
- The diaphragm
- The intercostal muscle
 The intercostal muscles
They are located intercostal spaces, the spaces between the ribs;there we have
the: External oblique + internal oblique
★The typical rib ★
usually has a head ,neck and tubercle ,and
the angle that goes into the groove ,it has a
costal groove, it has a costal cartilage that
extends to the sternum anteriorly and inserts
into the lateral border of the sternum.
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★The atypical rib★
as you can see ,it's the 1st rib ,it has a head,
neck and tubercle but it has a little bit of an
angle ,it has 2 grooves for the scaleni (anterior
+ middle). You can also see it has a medial and
a lateral border with smaller costal cartilage
that extends to the inferior surface of the
clavicle as well as the lateral border of the
sternal manubrium.
The 11th and 12th ribs are mainly called the Floating Ribs, there is a
debate about calling them Atypical or typical ribs, since they are short and
have no cartilage.
You might want to take a look on these photos
illustrating the thoracic vertebrae, the Dr.
mentioned them fuzzily :P
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In the intercostal space we have 3 types of muscles:
The internal oblique muscles and the external oblique, those which fill
the intercostal space anteriorly. The third type is the innermost intercostals
which are located within a very thin fashion and have small fibers .
 The external oblique practically extends all the way from the back into
the anterior aspect, it begins posteriorly, its direction is downward
medially, and practically this muscle is cut after two third of its distance
and replaced by an aponeurosis ,so you will see aponeurosis with the
same fiber direction inferiorly and medially.
 The internal oblique is the opposite, it will begin from the anterior with
a direction downward laterally and it begins with muscle and before it
reaches the posterior aspect of the intercostal space, it will be replace by
aponeurosis ,so the aponeurosis here is different and will help in
respiration.
 The innermost muscles, the muscles which immediately behind them
the parietal plural can be seen.
 Supcostalis muscles, those muscles are very small, you can see them
only from the medial or the inner aspect of the thorax anteriorly and they
originate from the inner surface of one rib, and are inserted into the inner
surface of the second or third rib below, near its angle.
 Transversus thoracis muscle
They are either the horizontal or vertical, located in the posterior between the
transverse processes and the part of the rib.
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(slide 46)
*These are the intercostal arteries and nerves and how the neurovascular
bundle is located in the groove, they will wind around and irrigate most of the
intercostal muscles.
(slide 48)
*This is how the pleural effusion tap is done; the needle is guided by the
superior border not by the inferior border of the rib, to prevent injuring the
neurovascular bundle.
**check the slides for more pictures, illustrations, and tables :D
The End
This part done by your colleague : Suadad Al-Ani
‫ يا ريت يتم تبليغي على كروب الدفعة‬.. ‫ رجاءا اذا الحظتوا اي معلومة خاطئة‬.. ‫اعتذر عن اي خطأ مسبقا‬
‫موفقين جميعا‬
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