the musculature of the head
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THE MUSCULATURE OF THE HEAD
The Two Groups of the Muscles of the Head
1. Craniofacial muscles- related mainly to the orbital margins and eyelids, the external nose and nostrils, the lips, the cheeks and mouth, the pinna, scalp, and cervical skin. These are collectively referred to as the muscles of facial expression.
Common Characteristics of the Muscles of Facial Expression
All are inserted into the skin of the face;
All are supplied by the muscular branches of the facial nerve
2. Masticatory muscles-- concerned primarily with the
movements of the temporomandibular joint.
The Musculature of the Head
The craniofacial muscles
The CraniofacialMuscles The craniofacial
muscles receive their innervation from the branches of the facial nerve.
They are grouped as:1. epicranial2. circumorbital and palpebral3. nasal4. buccolabial
1. The Epicranial Muscles
The epicranius is made up of two main parts:
1. Occipitofrontalis
2. Temporoparietalis
The Epicranius
1. Occipitofrontalis- covers the dome of the skull from
the highest nuchal lines to the eyebrows. It is a broad, musculofibrous layer consisting of four thin, quadrilateral parts- two occipital and two frontal- connected by the galea aponuerotica.
The Epicranius
2. Temporoparietalis- variably developed sheet of muscle that lies between the frontal parts of the occipitofrontalis and the anterior and superior auricular muscles.
Superficial fascia of the scalp
- is firm, dense and fibro adipose, and adheres closely to bothe skin and the underlying epicranius, including its epicranial aponeurosis, the galea aponuerotica. Posteriorly it is continuous with the superficial fascia of the back of the neck. Laterally it is prolonged into the temporal region, where it is looser in texture.
The Muscles of the Scalp
MuscleMuscle ActionAction
FrontalisFrontalis Pulls the scalp up and backPulls the scalp up and back
OccipitalisOccipitalis Pulls the scalp backward and Pulls the scalp backward and forward forward
2. Circumorbital and Palpebral Muscles
This group of muscle if composed of the
following:1. orbicularis oculi,
2. corrugator supercilii, 3. and levator palpebrae superioris.
Orbicularis Oculi
- is a broad, flat elliptical muscle which surrounds the circumference of the orbit and spreads into the eyelids, anterior temporal region, infraorbital cheek, and superciliary region. It has three main parts:
1. Orbital2. Palpebral3. Lacrimal
MuscleMuscle ActionAction
Orbital partOrbital part Closes eyes forcefullyCloses eyes forcefully
Palpebral partPalpebral part Closes the eye gentlyCloses the eye gently
Lacrimal partLacrimal part Squeezes lubricating tears Squeezes lubricating tears against the eyeballagainst the eyeball
Corrugator Supercilii
- a small pyramidal muscle located at the medial end of each eyebrow, deep to the frontal part of the occipitofrontalis and orbicularis oculi, with which it is partially blended.
MuscleMuscle ActionActionCorrugator superciliiCorrugator supercilii Vertical wrinkling of the Vertical wrinkling of the
bridge of the nose as in bridge of the nose as in frowningfrowning
3. Nasal Muscles
The nasal muscle group is composed of the following muscles:
1. Procerus2. Nasalis3. Depressor
septi
Procerus
- is a small pyramidal slip close to, and often partially blended with, the medial side of the frontal part of the occipitofrontalis muscle.
Nasalis
- consists of transverse and alar parts which may be continuous at their origins. The transverse part is also known as the compressor nares and the alar part is the dilator nares.
Depressor Septi
- is often regarded to as part of the dilator naris.
MuscleMuscle ActionAction
Depressor septiDepressor septi Draw the septum downwards Draw the septum downwards to narrow the nostrilsto narrow the nostrils
MuscleMuscle ActionAction
ProcerusProcerus Transverse wrinkling of the Transverse wrinkling of the bridge of the nosebridge of the nose
NasalisNasalis
CompressorCompressor
NaresNaresCompresses the nostrilsCompresses the nostrils
Dilator NaresDilator Nares Dilates or flares the nostrilsDilates or flares the nostrils
4. Buccolabial Muscles
The shape of the buccal orifice and the posture of the lips are controlled by a complex three-dimensional assembly of muscular slips. These include:
I. Elevators, retractors, and evertors of the upper lip
II. Depressors, retractors, and evertors of the lower lip
III. A compound sphincter
I. elevators, retractors, and evertors of the upper lip :
levator labii superioris alaque nasi,
levator labii superioris,
zygomaticus major and minor,
levator anguli oris,
and risorius
Depressors, retractors, and evertors of the lower lip
depressor labii inferioris,
depressor anguli oris, and
mentalis
A compound sphincter:
orbicularis oris,
accessory muscles to the
orbicularis oris
incisivus superior, and
incisivus inferior
MuscleMuscle ActionAction
Levator labii superioris alaque Levator labii superioris alaque nasinasi
Elevate the ala of the nose and Elevate the ala of the nose and the upper lipthe upper lip
Zygomaticus majorZygomaticus major Draws the angle of the mouth up Draws the angle of the mouth up and back as in smiling or laughingand back as in smiling or laughing
Zygomaticus minorZygomaticus minor Deepen the nasolbial groove as in Deepen the nasolbial groove as in sorrowsorrow
MuscleMuscle ActionAction
Levator labii superiorisLevator labii superioris
Elevates the upper lip and Elevates the upper lip and flares the nostrilsflares the nostrils
Gives the expression of Gives the expression of sadnesssadness
Contraction of the whole Contraction of the whole muscle gives the expression muscle gives the expression of disdain or doubtof disdain or doubt
MuscleMuscle ActionAction
Levator anguli oris or caninusLevator anguli oris or caninus Elevates the angle of the Elevates the angle of the mouth (muscle of happiness)mouth (muscle of happiness)
MentalisMentalis Elevate the chin. It also Elevate the chin. It also causes trembling of the chin. causes trembling of the chin. It wrinkles the skin of the chin It wrinkles the skin of the chin as in disdain or doubt.as in disdain or doubt.
MuscleMuscle ActionAction
RisoriusRisorius Draw the anglef the mouth Draw the anglef the mouth laterally, giving an expression laterally, giving an expression of strain or tensenessof strain or tenseness
Depressor labii inferiorisDepressor labii inferioris Depresses the lower lip as in Depresses the lower lip as in “irony”“irony”
Depressor anguli oris or Depressor anguli oris or TriangularisTriangularis
Depresses the angle of the Depresses the angle of the mouthmouth
MuscleMuscle ActionAction
BuccinatorBuccinator
Or Bugler’s or Trumpeter’s Or Bugler’s or Trumpeter’s musclemuscle
Draw the angle of the mouth Draw the angle of the mouth laterally and to press the laterally and to press the cheeks against the teeth cheeks against the teeth while chewing. Useful in while chewing. Useful in mastication, swallowing, mastication, swallowing, whistling, sucking, and whistling, sucking, and blowingblowing
MuscleMuscle OriginOrigin InsertionInsertion ActionAction Cranial Cranial NerveNerve
Orbicularis Orbicularis orisoris
Extrinsic Extrinsic fibers: fibers:
From From insertions insertions of of circumoral circumoral musclesmuscles
Intrinsic Intrinsic fibers:fibers:
From the From the incisive incisive fossae of fossae of the the mandible mandible and and maxillamaxilla
Pass Pass around the around the mouth mouth within the within the lips as a lips as a sphinctersphincter
Pass Pass obliquely obliquely forward forward and insert and insert into the into the skin of the skin of the liplip
CompresseCompresses the lips s the lips against the against the anterior anterior teeth, teeth, closes the closes the mouth, and mouth, and protrudes protrudes the lipsthe lips
VII - VII - zygomatic, zygomatic, buccal and buccal and mandibular mandibular branchesbranches
MuscleMuscle OriginOrigin InsertionInsertion ActionAction Cranial Cranial NerveNerve
PlatysmaPlatysma-thin, sub-thin, sub-
cutaneous cutaneous quadrilaterquadrilateral al muscular muscular sheet sheet covering covering the upper the upper part of the part of the chest, side chest, side of the neck of the neck and lower and lower part of the part of the face face
Skin and Skin and superficial superficial fascia of fascia of the the pectoral pectoral and deltoid and deltoid regionsregions
The fibers The fibers are are directed directed upward upward and and forward to forward to be inserted be inserted into the into the lower lower border of border of the the mandiblemandible
Retract Retract and and depress depress the angle the angle of the of the mouthmouth
VII - VII - cervical cervical branchbranch
Muscles of the External Ear
Muscles of the External Ear
MuscleMuscle ActionAction
Anterior auricularAnterior auricular Pulls the ear forwardPulls the ear forward
Posterior auricularPosterior auricular Pulls the ear backwardPulls the ear backward
Superior auricularSuperior auricular Pulls ear superiorlyPulls ear superiorly
COMMON FACIAL EXPRESSIONS
THE MUSCLES OF MASTICATION
The muscles of mastication includes:
1. Masseter2. Temporalis3. Medial Pterygoid4. Lateral Pterygoid
Functions of the Muscles of Functions of the Muscles of MasticationMastication
To move the mandible To secure then stabilize the mandibular
positions To determine the direction of mandibular
movements
The Masseter Muscle
The masseter muscle is a small quadrilateral muscle that covers most of the lateral aspect of the ramus of the mandible. Lying superficial to this muscle is a portion of the parotid gland, the parotid duct, the transverse facial artery, and the various branches of the facial nerve.
The Masseter Muscle
MuscleMuscle ActionActionMasseterMasseter
Superficial headSuperficial head ElevationElevation
(bilateral)(bilateral)
Ipsilateral excursionIpsilateral excursion
(unilateral)(unilateral)
ProtrusionProtrusion
(bilateral (bilateral
superficialsuperficial
head)head)
Deep headDeep head RetrussionRetrussion
(bilateral)(bilateral)
The Masseter Muscle
The Temporalis Muscle
The temporalis muscle is fan-shaped, with the periphery of the fan attached to the side of the skull and the handle of the fan attached to the coronoid process of the mandible. The muscle is covered by a strong membranous sheet of fascia, which attaches superiorly to the superior temporal line. Below, the fascia splits to attach to the medial and lateral aspects of the zygomatic arch.
The Temporalis
MuscleMuscle ActionActionTemporalisTemporalis Elevation Elevation
(bilateral)(bilateral)
Ipsilateral excursionIpsilateral excursion
(unilateral)(unilateral)
RetrussionRetrussion
(bilateral)(bilateral)
The Temporalis
The Medial Pterygoid
The medial and the lateral pterygoids are the occupants of the infratemporal fossa.
The medial pterygoid muscle is almost a mirror-like image of the masseter muscle. It is rhomboidal and runs practically in the same direction on the inner surface of the mandible.
The Medial Pterygoid
MuscleMuscle ActionAction
MedialMedial
PterygoidPterygoidElevation Elevation
(bilateral)(bilateral)
ProtrussionProtrussion
(bilateral)(bilateral)
Contralateral excursionContralateral excursion
(unilateral(unilateral
The Medial Pterygoid
The Lateral Pterygoid Muscle The lateral pterygoid is almost triangular
in shape with two distinct heads, inferior and superior head, each with contrasting functions. It is the only muscles of the four muscles of mastication to occupy primarily a horizontal position.
The Lateral Pterygoid
MuscleMuscle ActionActionLateral pterygoidLateral pterygoid
Inferior headInferior head
DepressionDepression
(bilateral)(bilateral)
ProtrussionProtrussion
(bilateral)(bilateral)
Contralateral excursionContralateral excursion
(unilateral)(unilateral)
Lateral pterygoid Lateral pterygoid
Superior headSuperior head
ElevationElevation
-particularly during power -particularly during power strokestroke
The Lateral Pterygoid
The Accessory Muscles of Mastication Othes muscles
that active in mastication include the suprahyoid and infrahyoid muscles of the neck. Both groups of muscles are active in helping to depress the mandible.
Summary of Actions of the Muscles of Mastication
Elevation:
1. the right and left temporalis
2. the right and left masseter
3. the right and left medial pterygoid muscles
Summary of Actions of the Muscles of MasticationDepression:1. the inferior head
of the right and left lateral pterygoid muscles
2. the right and left suprahyoid muscles of the neck
3. the right and left infrahyoid muscles of the neck
Summary of Actions of the Muscles of MasticationProtrusion1. the right and
left lateral pterygoid muscles
2. the right and left medial pterygoid muscles
3. the right and left superficial heads of the masseter muscles
Summary of Actions of the Muscles of MasticationRetrussion1.The posterior
fibers of the right and left temporalis muscles
2. deep heads of the right and left masseter muscles
Summary of Actions of the Muscles of MasticationRight Lateral
Excursion
1. the right masseter
2. the right temporalis
3. the left medial pterygoid
4. the left lateral pterygoid
Summary of Actions of the Muscles of MasticationLeft Lateral
Excursion1. the left
masseter2. the left
temporalis3. the right
medial pterygoid
4. the right lateral pterygoid
The muscles of the eyeball
The Eye Muscles
- Composed of the 7 muscles of the eye- Lateral rectus is supplied by the
Abducent N.- Superior oblique is supplied by the
Trochlear N.- The rest is supplied by the Oculomotor
N.
The muscles of the tongue
The Muscles of the Tongue
Extrinsic muscles are responsible for changing position of the tongue.
MuscleMuscle ActionAction
GenioglossusGenioglossus Retract and depress the Retract and depress the tonguetongue
HyoglossusHyoglossus Depress the tongueDepress the tongue
StyloglossusStyloglossus Pull the tongue upwards and Pull the tongue upwards and backwardsbackwards
The Muscles of the Tongue
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. Transverse muscles
- narrows the tongue.3. Vertical muscles
- flattens the tongue.
A Summary of the Actions of the Tongue1. Protrussion : genioglossus2. Retrussion : hyoglossus, styloglossus,
genioglossus3. Depression : genioglossus, hyoglossus4. Elevation : styloglossus5. Shortening : longitudinal intrinsic
fibers6. Narrowing : transverse intrinsic fibers7. Flattening : vertical intrinsic fibers
The muscles of the soft palate
Muscles of the Soft Palate
Muscles of the Soft Palate
MuscleMuscle ActionAction
Palatopharyn-geusPalatopharyn-geus Elevates the pharynx and larynxElevates the pharynx and larynx
Closes the oropharyngeal Closes the oropharyngeal isthmusisthmus
PalatoglossusPalatoglossus Closes the oropharyngeal Closes the oropharyngeal isthmusisthmus
UvularUvular Raises the uvula to help seal oral Raises the uvula to help seal oral from nasal pharynxfrom nasal pharynx
Muscles of the Soft Palate
MuscleMuscle ActionAction
Levator veli palatiniLevator veli palatini Elevates palate during Elevates palate during swallowing, yawningswallowing, yawning
Tensor veli palatiniTensor veli palatini Tenses the palate and opens Tenses the palate and opens the mouth of auditory tube the mouth of auditory tube during swallowing and yawningduring swallowing and yawning
Muscles of the Soft Palate