Muscles of Form Muscles of Form and Expressionand Expression

IntroductionIntroduction Muscular action forms Muscular action forms prominencesprominences, , foldsfolds, , hollowshollows, , groovesgrooves, and , and furrowsfurrows..

Repetition of muscular actions leaves Repetition of muscular actions leaves characteristic signs on the face.characteristic signs on the face.

Gravitational pull has an effect on Gravitational pull has an effect on features:features:

Horizontal position – laterally and Horizontal position – laterally and posteriorlyposteriorly

Vertical position – inferiorlyVertical position – inferiorly

Introduction (con’t)Introduction (con’t) Furrows run vertically on horizontal Furrows run vertically on horizontal

muscles and laterally on vertical muscles and laterally on vertical musclesmuscles

Origin – where the muscle is attached Origin – where the muscle is attached to a fixed pointto a fixed point

Insertion – where the muscle is Insertion – where the muscle is attached to a movable pointattached to a movable point

Construction of MusclesConstruction of Muscles

Muscles are described by the Muscles are described by the following:following:

Action – levatator palpebrae superiorisAction – levatator palpebrae superioris Number of heads/fibers – triceps brachiiNumber of heads/fibers – triceps brachii Location – temporalis Location – temporalis Shape – trapeziusShape – trapezius Origin and insertion – occipitofrontalisOrigin and insertion – occipitofrontalis

Muscles of the CraniumMuscles of the Cranium Occipitofrontalis/epicranius (1)Occipitofrontalis/epicranius (1)

Origin and insertionOrigin and insertion 2 broad bellies separated by an 2 broad bellies separated by an aponeurosisaponeurosis:: Occipital belly – quadrilateral in form; draws Occipital belly – quadrilateral in form; draws

the scalp backwardthe scalp backward Frontal belly – quadrilateral muscle slightly Frontal belly – quadrilateral muscle slightly

larger that occipitalis; creates transverse larger that occipitalis; creates transverse furrows across the foreheadfurrows across the forehead

Auricular muscles (3)Auricular muscles (3) Effect movement of the earEffect movement of the ear No effect on surface formNo effect on surface form

Muscles of MasticationMuscles of Mastication

Temporalis (2)Temporalis (2) Broad and fan-shapedBroad and fan-shaped Strongest of the chewing musclesStrongest of the chewing muscles No effect on surface formNo effect on surface form

Masseter (2)Masseter (2) Thick, quadrilateral muscle located Thick, quadrilateral muscle located

on the side of the faceon the side of the face Named for action – chewingNamed for action – chewing When contracted, raises lower jawWhen contracted, raises lower jaw

Muscles of Mastication (con’t)Muscles of Mastication (con’t)

Pterygoideus medialis (2) and Pterygoideus medialis (2) and lateralis (2)lateralis (2)

Permit side to side movement of the Permit side to side movement of the lower jawlower jaw

No influence on surface formNo influence on surface form

Muscles of the EyelidsMuscles of the Eyelids Obicularis oculi (2)Obicularis oculi (2)

Round muscle; surrounds eyelids and Round muscle; surrounds eyelids and portion of cheekportion of cheek

Lateral angle creates permanent folds – Lateral angle creates permanent folds – optic facial sulci – also known as optic facial sulci – also known as “crow’s feet”“crow’s feet”

Corrugator (2)Corrugator (2) Also known as “the frowning muscle”Also known as “the frowning muscle” Creates the vertical interciliary sulciCreates the vertical interciliary sulci

Muscles of the Eyelids (con’t)Muscles of the Eyelids (con’t)

Levator palpebrae superioris (2)Levator palpebrae superioris (2) Elevates the upper eyelidElevates the upper eyelid Superior palpebrae sulcus located on Superior palpebrae sulcus located on

the upper eyelidthe upper eyelid

Muscles of the NoseMuscles of the Nose

ProcerusProcerus Long, thin muscle over the bridge of the Long, thin muscle over the bridge of the

nose and between the eyes; merges nose and between the eyes; merges with frontalis musclewith frontalis muscle

Upon contraction, creates transverse Upon contraction, creates transverse interciliary sulci and pull the medial interciliary sulci and pull the medial ends of the eyebrows downwardends of the eyebrows downward

Muscles of the MouthMuscles of the Mouth

Obicularis orisObicularis oris Round muscle that encircles the Round muscle that encircles the

mouth that also consists of other mouth that also consists of other facial musclesfacial muscles

Contraction closes the lipsContraction closes the lips As a result of loss of teeth, vertical As a result of loss of teeth, vertical

sulci form on the mucous sulci form on the mucous membranesmembranes

Muscles of the MouthMuscles of the Mouth

Quadratus labii superiorisQuadratus labii superioris Consists of :Consists of :

levator labii superioris alaeque nasi (2) – levator labii superioris alaeque nasi (2) – “common elevator”“common elevator”

levator labii superioris (2) – lateral to levator labii superioris (2) – lateral to common elevatorcommon elevator

zygomaticus minor (2) – lateral to previouszygomaticus minor (2) – lateral to previous Contraction (along with the levator anguli Contraction (along with the levator anguli

oris) creates the nasolabial foldoris) creates the nasolabial fold

Muscles of the Mouth (con’t)Muscles of the Mouth (con’t) Levator anguli oris (2)Levator anguli oris (2)

Located in the area of the canine Located in the area of the canine teethteeth

Helps to create the nasolabial fold Helps to create the nasolabial fold and angular oris eminenceand angular oris eminence

Zygomaticus majorZygomaticus major Lateral to quadratusLateral to quadratus Upon contraction, draws the angle of Upon contraction, draws the angle of

the mouth backward and upwardthe mouth backward and upward Also known as “the laughing muscle”Also known as “the laughing muscle”

Muscles of the Mouth (con’t)Muscles of the Mouth (con’t)

BuccinatorBuccinator Also known as “the trumpeter’s Also known as “the trumpeter’s

muscle”muscle” Located in the soft area of the cheekLocated in the soft area of the cheek Responsible for vertical furrows Responsible for vertical furrows

(bucco-facial sulci also known as (bucco-facial sulci also known as dimples)dimples)

Muscles of the Mouth (con’t)Muscles of the Mouth (con’t) Risorius (2)Risorius (2)

Located superficial to the buccinatorLocated superficial to the buccinator Upon contraction, retracts the corners Upon contraction, retracts the corners

of the mouthof the mouth Depressor anguli oris (2)Depressor anguli oris (2)

Also known as triangularisAlso known as triangularis Upon contraction, depresses the Upon contraction, depresses the

corners of the mouthcorners of the mouth

Muscles of the Mouth (con’t)Muscles of the Mouth (con’t) Depressor labii inferiorisDepressor labii inferioris

Also known as quadratusAlso known as quadratus Upon contraction, pulls the lower lip Upon contraction, pulls the lower lip

down and slightly to the sidedown and slightly to the side Mentalis (1)Mentalis (1)

Wrinkles the chin and Wrinkles the chin and raises/protrudes lower lipraises/protrudes lower lip

Superficial to the mental eminenceSuperficial to the mental eminence May form a dimple in the chinMay form a dimple in the chin

Muscles of the NeckMuscles of the Neck Platysma (2)Platysma (2)

Broad, flat, and superficialBroad, flat, and superficial Upon contraction, lowers the jawUpon contraction, lowers the jaw Creates transverse furrows; platysmal sulciCreates transverse furrows; platysmal sulci

Sternocleidomastoideus (2)Sternocleidomastoideus (2) Measure the widest part of the neckMeasure the widest part of the neck Origin – the sternum and the clavicleOrigin – the sternum and the clavicle Insertion – the lateral surface of the mastoid Insertion – the lateral surface of the mastoid

processprocess Upon contraction, pulls the head sidewaysUpon contraction, pulls the head sideways

Muscles of the Neck (con’t)Muscles of the Neck (con’t)

Digastricus (2)Digastricus (2)Located below the body of the Located below the body of the

mandiblemandibleResponsible for cords of the neck in Responsible for cords of the neck in

older personsolder persons