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Muscles of Facial
Expression
Muscles of Facial
ExpressionAlex Forrest
Associate Professor of Forensic OdontologyForensic Science Research & Innovation Centre, Griffith University
Consultant Forensic Odontologist,
Queensland Health Forensic and Scientific Services,
39 Kessels Rd, Coopers Plains, Queensland, Australia 4108
Oral Biology
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COMMONWEALTH OF AUSTRALIA
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Do not remove this notice
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Learning ObjectivesLearning Objectives
You should be able to explain the embryological origin of
the muscles of facial expression, and to explain the
resulting common motor nerve and blood supply
You should be able to explain how the muscles of facial
expression are classified.
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Learning ObjectivesLearning Objectives
You should be able to demonstrate knowledge of the
principal functions of the major groups of muscles offacial expression in normal function.
You should be able to relate your understanding of
muscle functions to origins and insertions.
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Facial StructureFacial Structure
The basic form of the face is determined largely by the
underlying bony structures. These are covered by the soft
tissues which comprise muscles, subcutaneous fat and
other components.In some areas of the face, there is very little subcutaneous
soft tissue. These areas include the upper part of the nose,
the margins around the orbits, the forehead, and the areaover the zygomatic arches, and around the lower border of
the mandible.
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The bone can be palpated through the skin in these
areas, and as a result the skin tends to be relativelyimmobile in these regions.
Try this out on your own face (or that of a friend)
now
Facial StructureFacial Structure
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Facial StructureFacial Structure
Other regions in the face are separated from theunderlying bone by larger amounts of subcutaneous
tissue.
As a consequence, these areas tend to be more mobilewhen acted on by muscles, and are largely responsible for
the facial expressions.
These soft tissues are moved by a group of muscles
which is therefore called the subcutaneous muscles of
facial expression.
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ClassificationClassification
This muscle group shares a common nerve supply; all
motor supply to them comes from the facial nerve (VII).
You will recall that the facial nerve arises from the hyoid
arch or second branchial arch, and that the muscles of
facial expression, including the platysma, are derived fromthis arch as well.
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ClassificationClassification
You should note that not all the muscles supplied by VII are
classified as muscles of facial expression.
Specifically, the stylohyoid muscle and the posterior belly of
the digastric muscle are not included in this group,
although they are derived from the muscle element of the
2nd arch.
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ClassificationClassification
Other muscles also play a part in determining facialexpression, including the hypoglossal nerve (XII) (sticking
the tongue out) and the oculomotor nerve (III) (rolling the
eyes) but they are not classified in this group either.
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ClassificationClassification
Most muscles of facial expression have a bony origin and
insert into the soft tissue of the face.
Some have variations on this theme. The buccinator
originates from the pterygomandibular raphe, for
instance, and the orbicularis oris has no bony attachment
at all.
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ClassificationClassification
The muscles of facial expression can be classified into groups:
Muscles of the lips and cheeks
Muscles of the nose
Muscles of the eyelid
Muscles of the auricle of the ear
Muscles of the scalp
Platysma muscle
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Muscles of the
Lips and Cheeks
Muscles of the
Lips and Cheeks
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Lips and CheeksLips and Cheeks
The muscles of the lips and cheeks are divided into two layers:
Superficial muscles
Deep muscles
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Lips and CheeksLips and Cheeks
Superficial Layer:
Levator labii superioris alaquae nasi
Levator labii superioris
Levator anguli oris
Zygomaticus major & minor
Risorius
Depressor labii inferioris
Depressor anguli oris
Mentalis
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Lips and CheeksLips and Cheeks
Deep Layer:
Buccinator
Orbicularis oris
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Lips and CheeksLips and Cheeks
Levator labii superioris alaquae nasi
Levator labii superiorisLevator anguli oris
Zygomaticus major & minor
Risorius
Depressor labii inferioris
Depressor anguli oris
Mentalis
Superficial Layer:
Grays Anatomy, Longman, London, 35th Edition, 1973. p 496.
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Van De Graff, K. Human Anatomy, Iowa, Wm. C. Brown, 2nd Ed., 1988. p. 246
Levator labii superioris alaquae nasi
Levator labii superiorisLevator anguli oris
Zygomaticus major & minor
Risorius
Depressor labii inferioris
Depressor anguli oris
Mentalis
Superficial Layer:
Lips and CheeksLips and Cheeks
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Lips and CheeksLips and Cheeks
The muscles of thesuperficial layer
converge on lips and
enter them in a radial
distribution.
They originate on the
maxilla and mandible,
on the zygomaticbones, and from the
masseteric fascia.
Grays Anatomy, Longman, London, 35th Edition, 1973. p 304.
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Mandible, External Surface
Grays
Anatomy,
Longman,
London, 35th
Edition, 1973.p. 281.
Lips and CheeksLips and Cheeks
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Zygomatic Bone, Lateral Aspect
Grays
Anatomy,
Longman,
London, 35th
Edition, 1973.p. 309.
Lips and CheeksLips and Cheeks
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Many of these
superficial musclesconverge to insert on a
vertical
musculotendinous
raphe close to thecorner of the mouth.
This is known as the
modiolus, and is visible
through the skin as a
surface feature on the
face.
Lockhart RD, Living Anatomy. London, Faber & Faber 7th Ed. 1974, p. 16
Lips and CheeksLips and Cheeks
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Orbicularis OrisOrbicularis Oris
The fibres of
orbicularis orisform a kind of
sphincter around
and within the
lips.
Grays Anatomy, Longman, London, 35th Edition, 1973. p 496.
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Orbicularis OrisOrbicularis Oris
A small number of fibres attach to the maxilla and mandible in
the area associated with the sockets of the incisors (frenula).
Some fibres insert into the modiolus, while others insert on the
deep surfaces of the skin and mucous membrane of the mouth.
University of Queensland School of Dentistry 2001
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Orbicularis OrisOrbicularis Oris
Contraction of its fibres
draws the lips together,and tight contraction
causes pursing of the lips
as in pouting or whistling.
The lips are parted by
relaxation of the orbicularis
oris with simultaneous
contraction of the maxillaryand mandibular radiating
muscles.
Van De Graff, K. Human Anatomy, Iowa, Wm. C. Brown, 2nd Ed., 1988. p. 247
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BuccinatorBuccinator
The buccinator
muscle lies deep
within the cheeks andis closely related to
the buccal mucous
membrane.
Grays Anatomy, Longman, London, 35th Edition, 1973. p 496.
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BuccinatorBuccinator
Posteriorly it attaches
to the
pterygomandibular
raphe.Superiorly it attaches
to the alveolar process
of the maxilla, andbelow to that of the
mandible.
Modified from: Grays Anatomy, Longman, London,
35th Edition, 1973. p 499.
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BuccinatorBuccinator
Anteriorly its deeper fibres insert into the modiolus, and
the superficial ones insert into orbicularis oris.
Many of its fibres decussate prior to insertion to
strengthen the angle of the mouth.
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NoseNose
No detail need be known
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Orbit & EyelidOrbit & Eyelid
Each eyelid is given a degree of rigidity by a dense fibrous
structure, the tarsal plate.
Grays Anatomy, Longman, London, 35th Edition, 1973. p 498.
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Orbit & EyelidOrbit & Eyelid
The principal muscle of the eyelid region is the orbicularis
oculi. This comprises an orbital part, which overlies the bone
surrounding the orbital cavities, and a palpebral part which
is situated within the eyelids.
Grays Anatomy, Longman, London, 35th Edition, 1973. p 498.
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Orbit & EyelidOrbit & Eyelid
Both parts are attached to the medial palpebral ligaments at
the medial corners of the orbits, and to the adjacent bones.
Clemente CD, Anatomy, A Regional Atlas of the Human
Body, Munich, Urban & Shwarzenberg, 1975, Diagram 485.
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Orbit & EyelidOrbit & Eyelid
The orbital fibres radiate
around the orbits. They
insert into the overlying
skin.
The palpebral fibres insert
into the skin of the eyelids
and into the tarsal plateand lateral palpebral
ligament.
Grays Anatomy, Longman, London, 35th Edition,1973. p 496.
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Orbit & EyelidOrbit & Eyelid
The palpebral fibres ofthe orbicularis oculi close
the eyelids gently, as in
sleeping.
The orbital fibres draw
the eyebrows down as in
frowning, and help
forcibly close the eyes,as in an expression of
agony.
Grays Anatomy, Longman, London, 35th Edition,
1973. p 496.
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AuricleAuricle
No detail need be known
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ScalpScalp
The scalp consists of five layers. From superficial to deep,
these are:
S Skin
C Connective Tissue
A Aponeurosis
L Loose Connective Tissue
P Periosteum
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ScalpScalp
The epicranial
aponeurosis is atendinous sheet into which
the frontalis muscle
attaches anteriorly, and
the occipitalis muscleattaches posteriorly.
At the side of the skull, the
aponeurosis unites withthe underlying temporal
fascia.
Clemente CD, Anatomy, A Regional Atlas of the Human
Body, Munich, Urban & Shwarzenberg, 1975, Diagram 453.
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ScalpScalp
The aponeurosis is looselyattached to the underlying
periosteum, so some
movement is permitted.
The American Indians
used to take advantage of
this loose connection in
the process of scalpingtheir victims.
Clemente CD, Anatomy, A Regional Atlas of the Human
Body, Munich, Urban & Shwarzenberg, 1975, Diagram 453.
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ScalpScalp
The fibres of the frontalisattach to bone in the
region of the root of the
nose via fibres that are
known as the procerus
muscle.
Its intermediate fibres
insert on the skin of theeyebrows and forehead.
Clemente CD, Anatomy, A Regional Atlas of the Human
Body, Munich, Urban & Shwarzenberg, 1975, Diagram 453.
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ScalpScalp
The occipitalis attaches to the superior nuchal lines of the
temporalis muscle.
Together, the frontalis and occipitalis muscles can move
the aponeurosis and the overlying skin, but the amount of
movement varies between individuals.
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In the LabIn the Lab
As you study these structures, you will find that virtually all
textbooks referring to the anatomy of the head and neckcontain diagrams of these muscles to a greater or lesser
extent.
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In the LabIn the Lab
You should take the opportunity to examine skulls during
your practical sessions in detail.Feel the bones with your fingers. Can you feel
roughnesses in the bone surface in the places you expect
the muscles to attach?
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The End