The Muscles and Triangles of the Neck

8/8/2019 The Muscles and Triangles of the Neck

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The Muscles andThe Muscles andTriangles of the NeckTriangles of the Neck


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Regions of the NeckRegions of the Neck

To facilitate the seemingly complicated area, theTo facilitate the seemingly complicated area, theneck is divided into two major areas, orneck is divided into two major areas, ortriangles, by thetriangles, by the sternocleidomastoidsternocleidomastoidmusclemuscle. These are:. These are:

1.1. anterior triangleanterior triangle-- the area anterior to the SCM and belowthe area anterior to the SCM and belowthe inferior border of the mandible.the inferior border of the mandible.2.2. posterior triangleposterior triangle

-- the area posterior to the SCM and isthe area posterior to the SCM and islimited posteriorly by thelimited posteriorly by the trapeziustrapeziusmuscle.muscle.


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Sternocleidomastoid MuscleSternocleidomastoid Muscle

MuscleMuscle OriginOrigin InsertionInsertion ActionAction NerveNerveSupplySupply

SternocleidoSternocleido

mastoidmastoidmusclemuscle

Two heads:Two heads:

Sternal headSternal headmanubriummanubriumsternisterni

ClavicularClavicular

headhead-- Medial 2/3Medial 2/3of theof theclavicleclavicle

MastoidMastoid

process ofprocess ofthe of thethe of thetemporaltemporalbone andbone andlateral halflateral halfof theof thesuperiorsuperiornuchal line.nuchal line.

Bilateral:Bilateral:

Flex theFlex theneckneck

Single:Single:

Flex theFlex the

head andhead andlaterallylaterallyrotate to therotate to theoppositeoppositesideside

1. Spinal1. Spinal

accesoryaccesorynervenerve

2. Anterior2. Anteriorprimary ramiprimary ramiof spinalof spinal

nerves C2nerves C2and C3.and C3.


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Trapezius MuscleTrapezius MuscleMuscleMuscle OriginOrigin InsertionInsertion ActionAction NerveNerve

SupplySupplyTrapeziusTrapeziusmusclemuscle

ExternalExternaloccipitaloccipital

protruberanceprotruberance, the medial, the medialhalf of thehalf of thesuperiorsuperiornuchal line,nuchal line,thetheligamentumligamentumnuchae, andnuchae, andthe lowerthe lowercervical andcervical andall theall thethoracicthoracicspinesspines

FibersFibersoriginatingoriginating

from the headfrom the headinsert into theinsert into thelateral third oflateral third ofthe clavicle,the clavicle,and theand theremainingremainingfibers insertfibers insertinto theinto theacromionacromionprocess andprocess andspine of thespine of thescapulascapula

Contract toContract torotate androtate and

elevate theelevate thescapule. Itsscapule. Itscervicalcervicalportion, actingportion, actingbilaterally,bilaterally,can extendcan extendthe head andthe head andsingly, it cansingly, it canrotate therotate thehead and facehead and faceto theto theopposite sideopposite side

1. Spinal1. Spinalaccessoryaccessory

nervenerve

2. Anterior2. Anteriorprimary ramiprimary ramiof the spinalof the spinalnerves C3 andnerves C3 and

C4.C4.


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The Anterior TriangleThe Anterior Triangleof the Neckof the Neck


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Boundaries of the Anterior TriangleBoundaries of the Anterior Triangle

AnteriorAnterior-- median line of the neckmedian line of the neck

PosteriorPosterior anterior border of theanterior border of the

sternocleidomastoidsternocleidomastoidmusclemuscle

SuperiorSuperior-- inferior border of theinferior border of themandiblemandible

RoofRoof-- skin, superficial fascia,skin, superficial fascia,platysma, and investingplatysma, and investinglayer of deep cervicallayer of deep cervicalfasciafascia


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Muscles of theMuscles of theAnterior Triangle of the NeckAnterior Triangle of the Neck


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I. Infrahyoid MusclesI. Infrahyoid Muscles


OmohyoidOmohyoid Inferior belly:Inferior belly:

SuperiorSuperiorborder of theborder of the

scapulascapulaSuperior belly:Superior belly:

IntermediateIntermediatetendontendon

Inferior belly:Inferior belly:


SuperiorSuperiorbelly:belly:

Lower borderLower borderof the body ofof the body ofthe hyoidthe hyoidbonebone

Depresses theDepresses thehyoid bonehyoid boneand larynxand larynx

AnsaAnsacervicaliscervicalis(APR of C1,(APR of C1,

C2, C3)C2, C3)

SternohyoidSternohyoid Manubrium ofManubrium ofthe sternum,the sternum,posteriorposterioraspectaspect

Lower borderLower borderof the body ofof the body ofthe hyoidthe hyoidbonebone

Depresses theDepresses thehyoid bonehyoid boneand larynxand larynx

AnsaAnsacervicaliscervicalis(APR of C1,(APR of C1,C2, C3)C2, C3)


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Infrahyoid MusclesInfrahyoid Muscles


SternothyroidSternothyroid Manubrium ofManubrium ofthe sternum,the sternum,

posteriorposterioraspectaspect

Oblique line ofOblique line ofthyroidthyroid

cartilagecartilage

Depresses theDepresses thelarynxlarynx

AnsaAnsacervicaliscervicalis

(APR of C1,(APR of C1,C2, C3)C2, C3)

ThyrohyoidThyrohyoid Oblique line ofOblique line ofthyroidthyroidcartilagecartilage

Body andBody andgreater horngreater hornof hyoid bone,of hyoid bone,lower borderlower border

Depresses theDepresses thehyoid bonehyoid bone

ThyrohyoidThyrohyoidbranch of thebranch of thehypoglossalhypoglossalnervenerve


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II. Suprahyoid MusclesII. Suprahyoid Muscles


StylohyoidStylohyoid StyloidStyloidprocessprocess

Greater hornGreater hornof hyoidof hyoidbonebone

ElevatesElevateshyoid bonehyoid bone

Facial nerveFacial nerve

DigastricDigastric

(Posterior(Posteriorbelly)belly)

DigastricDigastricnotch of thenotch of thetemporaltemporalbone at thebone at the

base of thebase of theskullskull


Raises theRaises thehyoid bonehyoid bone


DigastricDigastric

(anterior(anteriorbelly)belly)


DigastricDigastricfossa of thefossa of themandiblemandible

Elevates theElevates thehyoid bonehyoid bone

Nerve to theNerve to themylohyoidmylohyoidmusclemuscle


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Suprahyoid MusclesSuprahyoid MusclesMuscleMuscle OriginOrigin InsertionInsertion ActionAction NerveNerve

SupplySupply

MylohyoidMylohyoid Mylohyoid lineMylohyoid lineon the medialon the medial

aspect ofaspect ofmandibularmandibularbodybody

Median rapheMedian rapheand body ofand body of

hyoidhyoid

Elevates theElevates thehyoid bone,hyoid bone,

base of thebase of thetongue, andtongue, andfloor of thefloor of themouthmouth

Nerve toNerve tomylohyoidmylohyoid

musclemuscle

GeniohyoidGeniohyoidmusclemuscle

InferiorInferiorborder genialborder genialtubercle oftubercle ofthe mandiblethe mandible

Body of hyoidBody of hyoidbonebone

Elevates hyoidElevates hyoidbone,bone,protractsprotractshyoid bonehyoid bone

APR of C1APR of C1


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Boundaries of the Anterior TriangleBoundaries of the Anterior Triangle

AnteriorAnterior-- median line of the neckmedian line of the neck

PosteriorPosterior anterior border of theanterior border of the

sternocleidomastoidsternocleidomastoidmusclemuscle

SuperiorSuperior-- inferior border of theinferior border of themandiblemandible

RoofRoof-- skin, superficial fascia,skin, superficial fascia,platysma, and investingplatysma, and investinglayer of deep cervicallayer of deep cervicalfasciafascia


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Subdivisions of theSubdivisions of the

Anterior TriangleAnterior Triangle1.1. DigastricDigastricTriangleTriangle

2.2. CarotidCarotid

triangletriangle3.3. Muscular orMuscular or

inferiorinferiorcarotidcarotid

triangletriangle4.4. SubmentalSubmental

triangletriangle


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1. Digastric Triangle1. Digastric Triangle

Boundaries:Boundaries:

1.1. SuperiorSuperior--lower border of the mandiblelower border of the mandible

2.2. AnteriorAnterior anterior belly of the digastricanterior belly of the digastric

3.3. PosteriorPosterior posterior belly of the digastricposterior belly of the digastric

4.4. FloorFloor --mylohoid and hyoglossus musclesmylohoid and hyoglossus musclesand superior contrictor muscle of theand superior contrictor muscle of thepharynxpharynx


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1. Digastric Triangle1. Digastric Triangle

Structures:Structures:1. Glands1. Glands

parotid andparotid andsubmandibularsubmandibular

2. Arteries2. Arteries

-- Internal and externalInternal and externalcarotid, facial, submental,carotid, facial, submental,posterior auricular,posterior auricular,superficial temporal andsuperficial temporal andlingual.lingual.

3. Veins3. Veins-- anterior facial andanterior facial andinternal jugular.internal jugular.

4. Nerves4. Nerves vagus,vagus,glossopharyngeal, facial,glossopharyngeal, facial,and hypoglossal.and hypoglossal.


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2. Carotid Triangle2. Carotid Triangle

Boundaries:Boundaries:1.1. SuperiorSuperior

posterior belly of theposterior belly of thedigastricdigastric

2.2. InferiorInferior

superior belly ofsuperior belly ofomohyoidomohyoid

3. Posterior3. Posterior anterior border of theanterior border of theSCMSCM

4.4. FloorFloor-- thyrohyoid muscle,thyrohyoid muscle,hyoglossus muscle, and thehyoglossus muscle, and themiddle and inferiormiddle and inferiorconstrictor muscles of theconstrictor muscles of thepharynx.pharynx.


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2. Carotid Triangle2. Carotid Triangle

Structures:Structures:1.1. OrgansOrgans

larynx and pharynx (lowerlarynx and pharynx (lowerpart)part)

2.2. ArteriesArteries-- CCA, facial, occipital,CCA, facial, occipital,

acending pharyngeal,acending pharyngeal,superior thyroid, and lingual.superior thyroid, and lingual.3.3. VeinsVeins

-- internal jugular, superiorinternal jugular, superiorthyroid, lingual, facial,thyroid, lingual, facial,occipital and ascendingoccipital and ascendingpharyngeal.pharyngeal.

4.4. NervesNerves

-- vagus, accessory,vagus, accessory,hypoglossal, ansahypoglossal, ansahypoglossi, external andhypoglossi, external andinternal laryngeal.internal laryngeal.


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3.3. Muscular or InferiorMuscular or Inferior

Carotid TriangleCarotid Triangle Boundaries:Boundaries:1.1. SuperoSupero--posteriorposterior

-- superior belly ofsuperior belly ofomohyoidomohyoid

2.2. inferoinfero--posteriorposterior-- anterior border ofanterior border ofSCMSCM

3.3. AnteriorAnterior-- median line of themedian line of theneckneck

4.4. FloorFloor-- sternohyoid andsternohyoid andsternothyroidsternothyroid


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3. Muscular or Inferior3. Muscular or Inferior

Carotid TriangleCarotid Triangle Structures:Structures:1.1. OrgansOrgans

thyroid andthyroid andparathyroid glands,parathyroid glands,

tracheatrachea2.2. ArteriesArteries

-- inferior thyroidinferior thyroid

3.3. VeinsVeins

-- internal jugularinternal jugular

4.4. NervesNerves

-- vagus, recurrentvagus, recurrentlaryngeal,laryngeal,sympathetic n.sympathetic n.


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4. Submental Triangle4. Submental Triangle


1.1. LateralLateral

-- two anterior belliestwo anterior belliesof the digastricof the digastric

2.2. PosteriorPosterior-- body of the hyoidbody of the hyoidbonebone

Structures:Structures:

1.1. Submental lymphSubmental lymphglandsglands

2.2. Beginning of theBeginning of theanterior jugular veinanterior jugular vein


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The Posterior TriangleThe Posterior Triangle

of the Neckof the Neck


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The Posterior Triangle of the NeckThe Posterior Triangle of the Neck


1.1. AnteriorAnterior-- posterior border of the SCM.posterior border of the SCM.

2.2. PosteriorPosterior-- anterior border of the trapeziusanterior border of the trapeziusmuscle.muscle.

3.3. InferiorInferior-- superior border of thesuperior border of theintermediate 1/3 of trhe clavicle.intermediate 1/3 of trhe clavicle.

4.4. SuperiorSuperior-- meeting of the trapezius andmeeting of the trapezius andSCM at the superior nuchal line.SCM at the superior nuchal line.

5.5. RoofRoof

-- formed by the skin, superficialformed by the skin, superficialfascia, platysma and investing layerfascia, platysma and investing layerof the deep cervical fascia.of the deep cervical fascia.

6.6. FloorFloor-- formed by several musclesformed by several muscles semispinalis capitis, apleniussemispinalis capitis, apleniuscapitis, levator scapulae, andcapitis, levator scapulae, andscalenius mediusscalenius medius


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Muscles of theMuscles of the

Posterior Triangle of the NeckPosterior Triangle of the Neck


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MuscleMuscle OriginOrigin InsertionInsertion ActionAction NerveNerve

PlatysmaPlatysma SuperficialSuperficial

fascia of thefascia of thedeltoid anddeltoid andpectoralpectoralregionsregions

InferiorInferior

border ofborder ofthethemandible,mandible,some fiberssome fiberssweepsweep

upward andupward andblend withblend withrisoriusrisorius

StretchesStretches

tight thetight theskin of theskin of theneck,neck,depressesdepressesthe mandiblethe mandible


SpleniusSpleniuscapitiscapitis

Lower partLower partof theof theligamentumligamentumnuchae,nuchae,lowerlowercervicalcervicalspinesspines

MastoidMastoidprocess andprocess andthe superiorthe superiornuchal linenuchal line

Bilateral:Bilateral:

Extends theExtends the

headheadIndividual:Individual:

Flexes theFlexes theheadheadlaterallylaterally

CervicalCervicalspinalspinalnervesnerves


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MuscleMuscle OriginOrigin InsertionInsertion ActionAction NerveNerve

LevatorLevator

scapulaescapulae

TransverseTransverse

processes ofprocesses ofC1 to C4C1 to C4

SuperiorSuperior

portion ofportion ofthe vertebralthe vertebralborder ofborder ofthe scapulathe scapula

Elevates andElevates and

rotates therotates thescapulascapula

DorsalDorsal

scapularscapularnervesnerves

ScaleniusScaleniusposteriorposterior

TransverseTransverseprocesses ofprocesses ofC5 and C6C5 and C6

SuperiorSuperioraspect of theaspect of thesecond ribsecond rib

Flexes theFlexes theneckneck

APR of C5 toAPR of C5 toC8C8

ScaleniusScaleniusMediusMedius

TransverseTransverseprocesses ofprocesses ofC2 to C7C2 to C7

SuperiorSuperioraspect of theaspect of thefirst ribfirst rib

Flexes theFlexes theneckneck

APR of C3APR of C3and C4and C4

ScaleniusScaleniusanterioranterior TransverseTransverseprocesses ofprocesses ofC3 to C6C3 to C6

ScaleneScalenetubercle oftubercle ofthe first ribthe first rib

ParticipatesParticipatesin forcedin forcedinspirationinspirationby elevatingby elevatingthe ribs andthe ribs andsternumsternum

APR of C5 toAPR of C5 toC8C8


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Subdivisions of theSubdivisions of thePosterior TrianglePosterior Triangle

1.1. Occipital TriangleOccipital Triangle

2.2. Supraclavicular TriangleSupraclavicular Triangle


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1. Occipital Triangle1. Occipital Triangle


1.1. AnteriorAnterior-- posterior border ofposterior border ofSCMSCM

2.2. PosteriorPosterior-- anterior border of theanterior border of theTrapezius M.Trapezius M.

3.3. SuperiorSuperior-- meeting between themeeting between thetrapezius and SCMtrapezius and SCM

4.4. InferiorInferior-- superior border of thesuperior border of theinferior belly ofinferior belly ofomohyoidomohyoid


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2. Supraclavicular or Subcalvian or2. Supraclavicular or Subcalvian orOmoclavicular TriangleOmoclavicular Triangle


1.1. AnteriorAnterior-- posterior border ofposterior border ofSCMSCM

2.2. SuperiorSuperior-- inferior border of theinferior border of theinferior belly ofinferior belly ofomohyoidomohyoid

3.3. InferiorInferior-- superior border ofsuperior border ofthe intermediate 1/3 ofthe intermediate 1/3 ofthe claviclethe clavicle


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Contents of the Posterior TriangleContents of the Posterior Triangle

1.1. ArteriesArteries-- subclavian artery, transverse cervical artery, occipital artery andsubclavian artery, transverse cervical artery, occipital artery andsuprascapular artery.suprascapular artery.

2.2. VeinsVeins

-- external jugular vein, anterior jugular vein, transverse cervical vein,external jugular vein, anterior jugular vein, transverse cervical vein,suprascapular and subclavian veins.suprascapular and subclavian veins.

3.3. NervesNerves-- spinal accessory nerve, cutaneous and muscular branches of thespinal accessory nerve, cutaneous and muscular branches of thecervical plexus, ansa cervicalis and root, trunk and divisions of thecervical plexus, ansa cervicalis and root, trunk and divisions of thebrachial plelxus.brachial plelxus.

4.4. Lymph glandsLymph glands-- supraclavicular lymph glands, and the lateral superior deep cervicalsupraclavicular lymph glands, and the lateral superior deep cervicallymph glands.lymph glands.

The Muscles and Triangles of the Neck

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