description of orofacial muscles

2. OROFACIAL
MUSCULATURE
BY:
Dr. Zainab Khan

3. CONTENT
• INTRODUCTION
• MUSCLES OF SCALP
• MUSCLES OF AURICLE
• MUSCLES OF EYE
• MUSCLES OF NOSE
• MUSCLES AROUND MOUTH
• MUSCLES OF MASTICATION
• MUSCLES OF TONGUE
• APPLIED ASPECT
• CONCLUSION
• REFERENCES

4. FACIAL MUSCLES-
The facial muscles, or the muscles of facial expression are subcutaneous muscles. They bring about
different facial expressions.
These have small motor units.
Embryologically:
They develop from the mesoderm of the second branchial arch, and are, therefore, supplied by the
facial nerve.
Morphologically:
They represent the best remnants of the panniculus carnosus, a continuous subcutaneous muscle
sheet seen in some animals. All of them are inserted into the skin.
Functionally:
Most of these muscles may be regarded primarily as regulators of the three openings situated on the
face, namely the palpebral fissures, the nostrils and the oral fissure. Each opening has a single
sphincter, and a variable number of dilators. Sphincters are naturally circular and the dilators radial in
their arrangement. These muscles are better developed around the eyes and mouth than around the
nose.
INTRODUCTION:

5. MUSCLE OF THE
SCALP:
OCCIPITOFRONTALIS MUSCLE :
Occipitofrontalis is a long and wide
muscleof the scalp spanning from
the eyebrows to the superior nuchal
lines of occipital bones.
Together with temporoparietalis,
it comprises the epicranial group
of the muscles of facial expression.

6. Origin:
Frontal belly (frontalis): Skin of eyebrow, muscles of forehead.
Occipital belly (occipitalis): (Lateral 2/3 of) superior nuchal line.
Insertion:
Epicranial aponeurosis.
Innervation:
Frontal belly: Temporal branches of facial nerve (CN VII).
Occipital belly: Posterior auricular nerve (branch of facial nerve (CN VII).
Blood supply:
Superficial temporal, ophthalmic, posterior auricular and occipital arteries.

7. Action:
Frontal belly: Elevates eyebrows, wrinkles skin of forehead.
Occipital belly: Retracts scalp.

8. TEMPOROPARIETRALIS
Lies between the anterior
and superior auricular
muscles.
ACTIONS:
1. Elevates the ear.
2. Pulls the scalp taut.

10. Situated around the ear
1 Auricularis anterior
2 Auricularis superior
3 Auricularis posterior
-These are vestigeal muscles
MUSCLES OF THE AURICLE

11. AURICULAR MUSCLES:
The auricular muscles are the extrinsic and intrinsic mucles
of the auricula, which connect it with the skull and scalp and
move the auricula as a whole:
The extrinsic auricular muscles are:
- The Auricularis anterior : the smallest of the three, is thin, fan-shaped, and its fibers are pale
and indistinct. It arises from the lateral edge of the galea aponeurotica, and its fibers converge to
be inserted into a projection on the front of the helix.
- The Auricularis superior : the largest of the three, is thin and fan-shaped. Its fibers arise from
the galea aponeurotica, and converge to be inserted by a thin, flattened tendon into the upper
part of the cranial surface of the auricula.
- The Auricularis posterior : consists of two or three fleshy fasciculi, which arise from the mastoid
portion of the temporal bone by short aponeurotic fibers. They are inserted into the lower part
of the cranial surface of the concha.

12. The intrinsic muscles are small muscular slips, which pass between the cartilaginous
parts of the auricle.
Actions:
The extrinsic muscles may play a role in positioning of the auricle to catch the sound,
while intrinsic muscles may change the shape of the auricle. Such movements are rarely
seen in human beings.
Anterior auricular:
pulls the ear upward & forward
Superior auricular:
elevates the ear
Post Auricular:
retracts & elevates the ear.

13. MUSCLES OF THE EYELIDS/ORBITOL OPENINGS:
Extraocular muscles-
-There are seven voluntary muscles in the orbit. Of these, six muscles move the
eyeball and one muscle moves the upper eyelid.
The muscles moving the eyeball are four recti and two oblique muscles. The one
which moves the upper eyelid is called levator palpebrae superioris:
1. Four recti muscles
(a) Superior rectus,
(b) Inferior rectus,
(c) Medial rectus, and
(d) Lateral rectus.
2. Two oblique muscles
(a) Superior oblique,
(b) Inferior oblique.
3. One levator palpebrae superioris

14. Superior Rectus
The superior rectus inserts at the anterior (front) portion of the eye, and its origin is behind the
eye on the common ring tendon. Its primary function is to elevate the eye, and it has a mild
secondary function of adduction and intorsion.
Inferior Rectus
The inferior rectus inserts at the anterior (front) portion of the eye, and its origin is behind the
eye on the common ring tendon. Its primary function is to depress the eye, and it has a mild
secondary function of adduction and extorsion.

15. Lateral Rectus
The lateral rectus inserts at the
anterior (front) portion of the eye,
and its origin is behind the eye on
the greater wing of the sphenoid
bone as well as the common ring
tendon. Its primary function is to
abduct the eye, and it has no
secondary function.
Medial Rectus
The medial rectus inserts at the
anterior (front) portion of the eye,
and its origin is behind the eye on
the common ring tendon. Its
primary function is to adduct the
eye, and it has no secondary
function.

16. Superior Oblique
The superior oblique is unique. It inserts on the superior, lateral (ear-side), and posterior (back) of the eye. The
anatomical origin is behind the eye on the lesser wing of the sphenoid bone, but the superior oblique muscle
acts a pully, and loops back trough a connective tissue sling called the trochlea. Even though it is positioned
above the eye, its unique use of the trochlea gives it a primary function is to intort the eye, and secondary
functions of depression and abduction.
Inferior Oblique
The inferior oblique is also. It inserts on the inferior, posterior, lateral portion of the eye. Its origin is on the
medial (middle) maxillary bone. Its primary function is extorsion, and its secondary functions are elevation and
abduction.

17. Levator palpebrae superioris (LPS) muscle
Origin: from undersurface of the lesser wing of sphenoid at the apex of the orbit, above the common tendinous
ring by a narrow tendon.
Insertion: the muscle broadens as it passes forwards from its origin and divides into three lamellae:
1. Upper lamella consisting of skeletal muscle penetrates the orbital septum passes through the fibres of
orbicularis oculi to be inserted into the skin of upper Eyelid
2. Intermediate lamella consisting of smooth muscle (superior tarsal muscle) is inserted on to the upper border of
the superior tarsal plate.
3. Lower lamella consisting of connective tissue is inserted on to the superior fornix of the conjunctiva.
Nerve supply:
1. Striped (skeletal muscle) part is supplied by the upper division of oculomotor nerve.
2. Unstriped (smooth muscle) part is supplied by the post-ganglionic sympathetic fibres from the superior cervical
ganglion.
Actions:
Elevation of the upper eyelid to open the eye.

18. THE MUSCLES ASSOCIATED WITH NASAL CAVITY ARE AS FOLLOWS:
1.Procerus.
2. Nasalis.
3. Depressor septi.
These muscles are poorly developed because anterior nares are open.
Procerus: It arises from nasal bone, passes upwards to be inserted into the skin of the
lower part of the forehead.
It produces transverse wrinkles across the bridge (root) of the nose as in frowning.
Nasalis: It consists of two parts: transverse part called compressor naris and alar part
called dilator naris.
1. Compressor naris arises form maxilla close to the nasal notch, passes upwards and
medially to form an aponeurosis across the bridge of nose where it becomes continuous
with its counterpart on the opposite side. It compresses the nasal aperture.
2. Dilator naris arises from maxilla from the margin of the
nasal notch and inserted into the lateral part of the ala of the nose.
It dilates the anterior nasal apertures as in deep inspiration. It also expresses the anger (sign
of omega).

19. Depressor septi: It arises from the incisive fossa of the maxilla and is
inserted into the lower mobile part of the nasal septum.
It fixes the nasal septum to allow dilatation of anterior nasal aperture by dilator
naris

20. MUSCLES AROUND MOUTH
The muscles around the mouth are responsible for the
movement of lips and cheek. These include:
1. Orbicularis oris: Acts as sphincter.
2. Nine muscles converging around the mouth act as
dilators.

21. Orbicularis Oris :
This complex muscle surrounds the oral orifice and forms
the greater part of the lips. It has extrinsic and intrinsic
portions. The major extrinsic (or superficial) portion is
composed of interlacing fibres of the muscles which converge
around the mouth for their insertion into the lips, viz. levator
anguli oris, depressor anguli oris, buccinator, etc. Most of the
fibres come from buccinator. The fibres of buccinator
converge towards the modiolus. At modiolus they form
chiasma. The uppermost and lowermost fibres pass straight
into their respective lips, whereas the middle fibres decussate,
so that the upper fibres pass into the lower lip, and lower into
the upper lip.
The intrinsic portion consists of fibres running obliquely
between the skin and mucus membrane of the lips, and
incisive slips, which pass laterally into the lips from the jaws
adjacent to the incisor teeth and interlace with the fibres of
peripheral part of orbicularis oris as they approach the modiolus.
Nerve supply:
Buccal branch of the facial nerve.

22. Actions:
Because of its complex nature, orbicularis oris is capable of producing wide
variety of movements of lips such as closing, pouting, pursing, twisting, etc.
Paralysis of orbicularis oris: The paralysis of one-half of orbicularis oris prevents
the proper closure of lips on that side. Consequently the speech is slurred and
the saliva escapes between the lips at the angle of the mouth (dribbling of
saliva from the angle of the mouth).

23. It arises from the frontal process of the maxilla and is inserted
into the ala of nose by one slip and to the upper lip by another
slip.
It elevates the upper lip and helps to dilate the nostril.
LEVATOR LABII SUPERIORIS ALAEQUE NASI

24. LEVATOR LABII SUPERIORIS
It arises from maxilla just above
the infraorbital foramen and is
inserted into the upper lip.
 Insertion:-Alar cartilage of
nose and skin over it;
some fibers into lateral
part of upper lip.
 Vascular Supply:-
Facial and maxillary artery.
Action : It elevates the upper
lip.

25. LEVATOR ANGULI ORIS
It arises from maxilla below the
infraorbital foramen and is inserted
into the angle of the mouth.
It lies deep to levator labii superioris.
 Vascular supply:- Facial &
Maxillary artery.
 Innervation:- Zygomatic &
Buccal branches of the facial
nerve.
Action:
It raises the angle of the mouth.

26. ZYGOMATICUS MINOR
It arises from zygomatic bone and is
inserted into the upper lip.
 Insertion:-Angle of the mouth.
 Vasuclar supply:- Facial artery.
 Innervation:- Zygomatic
& Buccal branches
of facial nerve.
Action:
Elevates & curls the upper lip
as in contempt, smugness or disdain

27. ZYGOMATICUS MAJOR
It arises from zygomatic bone and is
inserted into the angle of the mouth.
It draws the angle of the mouth
upward and laterally.
 Vasuclar supply:- Facial artery.
 Innervation:- Zygomatic
& Buccal branches
of facial nerve.
Action:
Draws the angle of the mouth
& laterally as in laughing/Smiling

28. DEPRESSOR LABII INFERIORIS
It arises from the anterior
oblique
line of the mandible and is
inserted into the lower lip.
Action:
It draws the lower lip
downwards and somewhat
laterally.

29. DEPRESSOR ANGULI ORIS
It arises from the posterior
part of the oblique line of
the mandible and is
inserted into the angle of
the mouth.
It draws the angle of the
mouth downwards and
laterally.
Action:
It expresses grief

30. RISORIUS
Risorius arises from parotid
fascia as a continuation of
posterior fibres of platysma
and is inserted into the angle
of the mouth.
Action:
It retracts the angle of the
mouth gently.

31. MENTALIS
Mentalis, a small conical
muscle arises from the
incisive
fossa of the mandible
and is inserted into the
skin of the
lower lip.
ACTION:
It puckers the chin and
protrudes the lower lip.

32. BUCCINATOR (Bugler’s muscle/trumpeter’s muscle) is
muscle of the cheek.
Origin: The buccinator arises from the following 4 sites:
1. Outer surface of the alveolar process of maxilla opposite
three molar teeth.
2. Fibrous band that extends from pterygoid hamulus to
maxillary tuberosity (pterygomaxillary raphe).
3. Pterygomandibular raphe, which extends from
pterygoid hamulus to the mandible behind the third
molar tooth.
4. Outer surface of the alveolar process of mandible
opposite three molar teeth.
After origin, the fibres run towards the mouth and fill the gap between the upper and lower jaws.
The fibres are arranged into upper, intermediate, and lower groups.
Insertion: The buccinator is inserted in a complicated manner into the upper and lower lips.
On reaching near the angle of the mouth:
(a) upper fibres pass into upper lip,
(b) lower fibres pass into the lower lip, and
(c) intermediate fibres decussate and as a result upper fibres of this group pass into lower lip and
lower fibres pass into the upper lip.

33. Nerve supply: Buccal branches of facial nerve.
Actions:
1. It flattens the cheek against the gum and
teeth, and thus prevents the accumulation of
food in the vestibule of mouth during
mastication.
2. It is responsible for blowing the cheek and
expelling the air between the lips from
inflated vestibule as in blowing the trumpet
(hence the name trumpeter’s muscle).

34. CLINICAL EXAMINATION
A few of the common facial expressions and the muscles
producing them are :
1 Smiling and laughing: Zygomatticus major
2 Sadness: Levator labii superioris and levator anguli oris
3 Grief: Depressor anguli oris
4 Anger: Dilator naris and depressor septi.
5 Frowning: Corrugator supercilii and procerus.
6 Horror, terror and fright: Platysma
7 Surprise: Frontalis
8Doubt: Mentalis
9 Grinning: Risorius
10 Contempt: Zygomaticus minor.
11. Closing the mouth: Orbicularis oris
12 Wistling: Buccinator, and orbicularis oris

35. MUSCLES OF MASTICATION
The muscles of mastication are
associated with movements of the jaw
(temporomandibular joint). They are one
of the major muscle groups in the head –
the other being the muscles of facial
expression. There are four muscles:
1. Masseter
2. Temporalis
3. Medial pterygoid
4. Lateral pterygoid
The muscles of mastication develop from
the first pharyngeal arch. Thus, they are
innervated by a branch of the trigeminal
nerve (CN V), the mandibular nerve.

36. MASSETER
The masseter muscle is the most powerful muscle of mastication. It is quadrangular in
shape and has two parts: deep and superficial.
The entirety of the muscle lies superficially to the pterygoids and temporalis, covering
them.
Attachments: The superficial part originates from maxillary process of the zygomatic
bone. The deep part originates from the zygomatic arch of the temporal bone. Both
parts attach to the ramus of the mandible.
Actions: Elevates the mandible, closing the mouth.
Innervation: Mandibular nerve (V3).

37. TEMPORALIS
• The temporalis muscle originates from the
temporal fossa – a shallow depression on the
lateral aspect of the skull. The muscle is
covered by tough fascia which can be
harvested surgically and used to repair a
perforated tympanic membrane (an operation
known as a myringoplasty).
• Attachments: Originates from the temporal
fossa. It condenses into a tendon, which
inserts onto the coronoid process of the
mandible.
• Actions: Elevates the mandible, closing the
mouth. Also retracts the mandible, pulling the
jaw posteriorly.
• Innervation: Mandibular nerve (V3).

38. MEDIAL PTERYGOID
• The medial pterygoid muscle has a
quadrangular shape with two heads:
deep and superficial. It is located
inferiorly to the lateral pterygoid.
• Attachments:
– The superficial head originates from the
maxillary tuberosity and the pyramidal
process of palatine bone.
– The deep head originates from the
medial aspect of the lateral pterygoid
plate of the sphenoid bone.
– Both heads attach to the ramus of the
mandible near the angle of mandible.
• Actions: Elevates the mandible, closing
the mouth.
• Innervation: Mandibular nerve (V3).

39. LATERAL PTERYGOID
• The lateral pterygoid muscle has a triangular
shape with two heads: superior and inferior. It
has horizontally orientated muscle fibres, and
thus is the major protractor of the mandible.
• Attachments:
– The superior head originates from the greater
wing of the sphenoid.
– The inferior head originates from the lateral
pterygoid plate of the sphenoid.
– The two heads converge into a tendon which
attaches to the neck of the mandible.
• Actions: Acting bilaterally, the lateral pterygoids
protract the mandible, pushing the jaw
forwards. Unilateral action produces the ‘side to
side’ movement of the jaw.
• Innervation: Mandibular nerve (V3).

40. MUSCLES OF THE TONGUE
EXTRINSIC MUSCLES –Responsible for
changing of tongue.
MUSCLE AND ITS ACTION
• Genioglossus
Retract and depress the tongue
• Hyoglossus
Depress the tongue
• Styloglossus
Pull the tongue upwards and backwards

41. • The Intrinsic Muscles:
1. Superior and inferior longitudinal muscles
 Located close to the dorsum of the tongue
 Shorten the length of the tongue and to curl the tip
of the tongue and back.
2. Tranverese muscles
 Narrows the tongue.
3. Vertical muscles
 Flattens the tongue.

42. SUMMARY OF THE ACTIONS OF THE
TONGUE
Protussion : Genioglossus,genioglossus
Retrussion: Hyoglossus, styloglossus,genioglossus
Depression: Genioglossus,hyoglossus
Elevation: Styloglossus
Shortening: Longitudinal intrinsic fibers
Norrowing : Transverse intrinsic fibers
Flattening : Vertical intrinsic fibers

43. APPLIED ASPECTS

44. MYOTONIA
• Myotonia congenita is a disorder that affects muscles used for movement
• Beginning in childhood, people with this condition experience bouts of sustained muscle tensing
(myotonia) that prevent muscles from relaxing normally.
• Myotonia can affect any skeletal muscles, including muscles of the face and tongue, it occurs most
often in the legs
• The two major types of myotonia congenita are known as Thomsen disease and Becker disease.
These conditions are distinguished by the severity of their symptoms and their patterns of
inheritance. Becker disease usually appears later in childhood than Thomsen disease and causes
more severe muscle stiffness, particularly in males

45. MYASTHENIA GRAVIS
It is characterized by weakness and rapid fatigue of any of the muscles under your voluntary control.
It's caused by a breakdown in the normal communication between nerves and muscles.
There's no cure for myasthenia gravis, but treatment can help relieve signs and symptoms, such as
weakness of arm or leg muscles, double vision, drooping eyelids, and difficulties with speech, chewing,
swallowing and breathing.
• Cholinesterase inhibitors. Medications such as pyridostigmine (Mestinon, Regonal) enhance
communication between nerves and muscles. These medications aren't a cure, but they can
improve muscle contraction and muscle strength in some people.
• Corticosteroids. Corticosteroids such as prednisone (Rayos) inhibit the immune system, limiting
antibody production. Prolonged use of corticosteroids, however, can lead to serious side effects,
such as bone thinning, weight gain, diabetes and increased risk of some infections.
• Immunosuppressants.

46. FACIAL HEMIATROPHY
Characterised by progressive
atrophy and wasting of
subcutaneous fat, skin,
cartilage,bone, muscle of
essentially half of the face.
•Most common early sign is
a painless cleft near midline
of face/forehead.
•Bluish hue may appear in
skin overlying atrophic fat.

47. FACIAL HEMIHYPERTROPHY
• Patients affected by condition
exhibit an enlargement which is
confined to one side of the
body, unilateral macroglossia
and premature development,
and eruption as well as
increased size of dentition.
• Cause is unknown, but has
been variously ascribed to
vascular or lymphatic
abnormaliities; CNS
disturbances; and chromosomal
abnormalities.

48. HEMIFACIAL MICROSOMIA
• This condition in which tissues on One side of face
are underdeveloped affecting primarily ear, mouth and
jaw areas.
• Sometimes both sides of face can be affected.

49. What conditions and disorders can
affect the facial muscles?
To function, the facial muscles get signals from the brain via the facial nerve. But sometimes, they can’t
receive those signals properly.
When the facial muscles cannot receive brain signals properly, that can cause:
Droopy or sagging appearance in the face.
Facial palsy (weakness).
Facial paralysis (inability to move parts of the face).
Trouble chewing, speaking or making facial expressions.
Drooling.
Symptoms can occur:
All over your face.
In one specific area.
On the left or right side.
On the top or bottom half.

50. Damage to the facial nerve and problems with the facial muscles can be caused by:
Autoimmune disease: Diseases such as Guillain-Barré syndrome or multiple sclerosis can cause facial palsy over
time.
Bell’s palsy: When swelling puts pressure on the facial nerve, Bell’s palsy can cause facial weakness or paralysis on
one or both sides of your face. It almost always leads to a complete inability to wrinkle your forehead. Bell’s palsy
happens suddenly but is usually temporary.
Head and neck cancer: In head and neck cancer, a growing tumor can interfere with facial muscle function over
time.
Infection: A bacterial or viral infection can cause inflammation of the facial nerve and problems in the muscles of
the face. Examples include ear infections, Lyme disease or Ramsay-Hunt syndrome.
Injury to the head or face: Facial trauma, such as a blow to the head or car accident, can damage the facial nerve
and facial muscles.
Stroke: A stroke occurs when a blood vessel in the brain is blocked or bursts. It can cause sudden facial weakness
or paralysis. Other signs may include paralysis on one side of the body, confusion, memory loss and trouble
communicating. A person who has had a stroke can usually still wrinkle the forehead, unlike with Bell’s palsy.

51. CONCLUSION
• The kownledge of the anatomy physiology and
mechanisms of these muscles are basic to
understand the movements.
• The masticatiory muscles include a vital part of
the oro facial structure and are important both
funtionally and structurally.

52. REFERENCES
• Gray's Anatomy (20th U.S. edition of
Gray's Anatomy of the Human Body,
published in 1918.
• Vishram Singh Textbook of Anatomy Head,
Neck, and Brain. (VOL-3) 2nd Edition.
• B.D.Chaurasia; Human Anatomy, 10th
edition.
• Grants; Atlas of Anatomy, 10th edition.
• Westbrook KE, Nessel TA, Varacallo
M. Anatomy, Head and Neck, Facial