ANTERIOR TRIANGLEANTERIOR TRIANGLE

It is in front of the sternomastoid It is in front of the sternomastoid musclemuscle..

BOUNDARIESBOUNDARIES

AnteriorlyAnteriorly: : midline of midline of the neckthe neck..

PosteriorlyPosteriorly: anterior : anterior border of border of sternomastoidsternomastoid..

SuperiorlySuperiorly: lower : lower margin of the body of margin of the body of the mandiblethe mandible..

BOUNDARIESBOUNDARIES

RoofRoof:: skin, superficial skin, superficial

fascia fascia (containing (containing platysma) and platysma) and thethe Investing Investing layerlayer of deep of deep cervical fasciacervical fascia..

SUBDIVISIONSSUBDIVISIONS

The anterior triangle The anterior triangle is subdivided byis subdivided by : :

The anterior and The anterior and posterior bellies of posterior bellies of the the digastricdigastric and and

The The superior bellysuperior belly of of omohyoidomohyoid into (4) into (4) smaller trianglessmaller triangles::

SUBDIVISIONSSUBDIVISIONS

SubmentalSubmental..Submandibular Submandibular ((DigastricDigastric))..

CarotidCarotid..MuscularMuscular

DIGASTRIC MUSCLEDIGASTRIC MUSCLE

The muscle has two bellies :Anterior and Posterior .

The posterior belly : arises from the mastoid process and inserted into the intermediate tendon.

The anterior belly attached to the lower border of body of mandible.

DIGASTRIC MUSCLEDIGASTRIC MUSCLE

Intermediate Intermediate tendontendon: :

It pierces the It pierces the insertion of insertion of stylohyoidstylohyoid..

It binds to the It binds to the hyoid bone by a hyoid bone by a loop of deep fascialoop of deep fascia..

DIGASTRIC MUSCLEDIGASTRIC MUSCLE

Nerve supply: The facial nerve

supplies the posterior belly .

The nerve to mylohyoid supplies the anterior belly.

DIGASTRIC MUSCLEDIGASTRIC MUSCLE

Action: Depression of the

mandible ORElevation of the

hyoid bone.

STYLOHYOIDSTYLOHYOID

It It originatesoriginates from the from the styloid processstyloid process..

It runs along the It runs along the upper border of the upper border of the posterior belly of posterior belly of digastricdigastric..

It is It is insertedinserted into the into the hyoid bone (between hyoid bone (between body and greater body and greater horn)horn)..

STYLOHYOIDSTYLOHYOID

Nerve supplyNerve supply: : Facial nerveFacial nerve..

ActionAction ::ElevationElevation of of

hyoid bonehyoid bone..

SUBMENTAL TRIANGLESUBMENTAL TRIANGLEIt lies below the chinIt lies below the chin..

Its boundaries areIts boundaries are::AnteriorlyAnteriorly: midline of : midline of

the neckthe neck..LaterallyLaterally: anterior belly : anterior belly

of digastricof digastric..

SUBMENTAL TRIANGLESUBMENTAL TRIANGLE

InferiorlyInferiorly : body : body of the hyoidof the hyoid..

Floor:Floor: mylohyoid mylohyoid musclemuscle..

MYLOHYOIDMYLOHYOID

It is a flat triangular sheet that supports the floor of the mouth and tongue.

It takes origin from the mylohyoid line of the mandible.

MYLOHYOIDMYLOHYOID

Insertion: The anterior fibers

are inserted into a fibrous raphe .

The posterior fibers are inserted into the body of hyoid bone.

MYLOHYOIDMYLOHYOID

Nerve supply : It is supplied by

the nerve to mylohyoid (from inferior alveolar of mandibular).

MYLOHYOIDMYLOHYOIDAction:

If the mandible is fixed, it elevates the floor of the mouth as in deglutition.

If the hyoid bone is fixed, it depresses the mandible and opens the mouth.

SUBMENTAL TRIANGLESUBMENTAL TRIANGLE

ContentsContents : : Submental lymph Submental lymph

nodesnodes..They receive They receive

lymph from the lymph from the tiptip of the tongue of the tongue..

DIGASTRIC TRIANGLEDIGASTRIC TRIANGLEIt lies below the body It lies below the body

of the mandibleof the mandible..It is bounded byIt is bounded by : :

AnteriorlyAnteriorly: anterior : anterior belly of digastricbelly of digastric..

PosteriorlyPosteriorly: posterior : posterior belly of digastric and belly of digastric and stylohyoidstylohyoid..

DIGASTRIC TRIANGLEDIGASTRIC TRIANGLE

SuperiorlySuperiorly:: lower border of lower border of

the body of the the body of the mandiblemandible..

FloorFloor:: mylohyoid and mylohyoid and

hyoglossus hyoglossus musclesmuscles..

DIGASTRIC TRIANGLEDIGASTRIC TRIANGLEContentsContents : :

A. Anterior partA. Anterior part: : ((11 ) )SubmandibularSubmandibular

salivarysalivary glandgland..((22 ) )Facial arteryFacial artery (deep to (deep to

gland)gland)..((33 ) )Facial veinFacial vein

((44 ) )submandibular lymph submandibular lymph nodesnodes (both superficial (both superficial to gland)to gland)..

DIGASTRIC TRIANGLEDIGASTRIC TRIANGLE

((55 ) )Hypoglossal Hypoglossal nervenerve..

((66 ) )Nerve and Nerve and vessels to vessels to mylohyoidmylohyoid..

DIGASTRIC TRIANGLEDIGASTRIC TRIANGLE

B. B. posterior partposterior part::11 . .Carotid sheathCarotid sheath

(carotid arteries (carotid arteries internal jugular internal jugular vein and vagus vein and vagus nerve)nerve)..

22 . .Lower part of Lower part of the the parotid parotid glandgland..

CAROTID TRIANGLECAROTID TRIANGLE

It lies behind the hyoid It lies behind the hyoid bonebone..

It is It is boundedbounded by by::SuperiorlySuperiorly : :

posterior belly of posterior belly of digastricdigastric..

InferiorlyInferiorly: superior belly : superior belly of omohyoidof omohyoid..

CAROTID TRIANGLECAROTID TRIANGLE

PosteriorlyPosteriorly:: anterior border of anterior border of

sternomastoidsternomastoid..FloorFloor : :

thyrohyoid, thyrohyoid, hyoglossushyoglossus , ,

middle and inferior middle and inferior constrictors of the constrictors of the pharynxpharynx..

CAROTID TRIANGLECAROTID TRIANGLE

ContentsContents:: ((11 ) )Carotid sheathCarotid sheath and and

its contentsits contents..((22 ) )Hypoglossal nerveHypoglossal nerve

and its descending and its descending branchbranch..

((33 ) )Acessory Acessory nervenerve..

CAROTID TRIANGLECAROTID TRIANGLE

((44 ) )Internal and Internal and External External laryngeal nerveslaryngeal nerves..

((55 ) )Deep cervicalDeep cervical lymph nodeslymph nodes..

CAROTID SHEATHCAROTID SHEATHIt is a condensation It is a condensation

of of deep cervical deep cervical fasciafascia..

It is attached to the It is attached to the base of the skull base of the skull superiorly and fuses superiorly and fuses with the with the pericardium pericardium inferiorlyinferiorly..

CAROTID SHEATHCAROTID SHEATHContentsContents: :

11 . .Common and Common and internal carotidinternal carotid arteriesarteries..

22 . .Internal jugular veinInternal jugular vein..33 . .Vagus nerveVagus nerve..

44 . .Deep cervical lymphDeep cervical lymph nodes form a chain nodes form a chain along the internal along the internal jugular veinjugular vein..

CAROTID SHEATHCAROTID SHEATH

It is crossed by It is crossed by the following the following nervesnerves::

GlossopharyngeaGlossopharyngeall..

HypoglossalHypoglossal..Spinal part of Spinal part of

acessoryacessory..

MUSCULARMUSCULAR TRIANGLETRIANGLE

It lies below the hyoid It lies below the hyoid bonebone..

It is It is boundedbounded by by : :AnteriorlyAnteriorly: :

midline of the neckmidline of the neck..SuperiorlySuperiorly : :

superior belly ofsuperior belly of omohyoidomohyoid..

MUSCULAR TRIANGLEMUSCULAR TRIANGLE

InferiorlyInferiorly:: anterior border of anterior border of

sternomastoidsternomastoidFloorFloor::

sternohyoidsternohyoid and and sternothyroidsternothyroid muscles muscles..

MUSCULAR TRIANGLEMUSCULAR TRIANGLE

BeneathBeneath the floor the floor lielie::

Thyroid glandThyroid gland..LarynxLarynx..

TracheaTrachea..EsophagusEsophagus..

INFRAHYOID MUSCLESINFRAHYOID MUSCLESThey are thin, strap They are thin, strap

like muscleslike muscles..They are composed They are composed

ofofSternohyoidSternohyoid..

SternothyroidSternothyroid..ThyrohyoidThyrohyoid..

OmohyoidOmohyoid..

INFRAHYOID MUSCLESINFRAHYOID MUSCLES

ActionAction: : ((11 ) )stabilization of stabilization of

the hyoid bone to the hyoid bone to make a base for the make a base for the movements of the movements of the tonguetongue..

((22 ) )Assist in the Assist in the movements of the movements of the larynx in larynx in swallowingswallowing..

INFRA HYOIDINFRA HYOID MUSCLESMUSCLES

Nerve supplyNerve supply: : All are supplied by All are supplied by

the the ansa cervicalis ansa cervicalis (C1,2&3)(C1,2&3) except except

Thyrohyoid Thyrohyoid (supplied (supplied by C1 through the by C1 through the hypoglossal nerve)hypoglossal nerve)..

INFRA HYOIDINFRA HYOID MUSCLESMUSCLES

OriginOrigin: : SternohyoidSternohyoid & &

SternothyroidSternothyroid: : posterior surface of posterior surface of

the manubriumthe manubrium..InsertionInsertion: :

Hyoid bone (lower Hyoid bone (lower border)border)..

Oblique line of thyroid Oblique line of thyroid cartilagecartilage..

INFRA HYOIDINFRA HYOID MUSCLESMUSCLES

ThyrohyoidThyrohyoid ::OriginOrigin : :

oblique line of oblique line of thyroid cartilagethyroid cartilage..

InsertionInsertion : : hyoid bone (lower hyoid bone (lower

border)border)..

INFRA HYOIDINFRA HYOID MUSCLESMUSCLES

OmohyoidOmohyoid: : Inferior bellyInferior belly: :

Origin : suprascapular Origin : suprascapular ligament and ligament and suprascapular notchsuprascapular notch..

Superior bellySuperior belly::OriginOrigin : :

intermediate tendonintermediate tendon..InsertionInsertion : hyoid bone : hyoid bone

(lower border)(lower border) . .