Anatomyoftheneck

Anteriortriangle- part2

Dr.MohamedElfiky

ProfessorofanatomyandEmbryology

Submandibularregion

DigastricMuscle

Stylohyoid

Posteriorbellyofdigastric

Anteriorbellyofdigastric

Origin : arises by two bellies 1. Anterior belly : from the digastric fossa on the lower border of the mandible close to the symphysis menti. 2. Posterior belly : from the mastoid notch on the medial side of the mastoid process Insertion : into the intermediate tendon which is attached to the hyoid bone by a fibrous bully. Nerve supply : 1. Anterior belly : by nerve to mylohyoid (from the

mandibular) because it develops from the first branchial arch.

2. 2.Posteriorbelly:fromthefacialnervebecauseitdevelopsfromthesecondbranchialarch.

Actions:1. Depressesthemandible2. 2.Elevatesthehyoidbone Mylohyoid

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1. Mastoid process with

sternomastoid.

2. Parotid gland : between the

mastoid process and the angle of the

mandible.

3. Angle of the mandible.

4. Submandibular salivary gland.

Superficial relations of post. Belly of digastric

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DeepRelationsofthePosteriorBellyofdigastrica. Three big vessels :

1. Internalcarotidartery

2. Externalcarotidartery.

3. Internaljugularvein

b.Threecranialnerves:

1.Vagus :liesbetweentheinternaljugularveinandtheintercarotidartery

(posteriorly).

2.Hypoglossal:betweentheinternaljugularveinandtheintocarotidartery

3.Accessorynerve:betweenthemuscleandtheinternaljugularvein

(C)Alongitsupperborder:

1. Posteriorauricularartery

2. 2.Stylohyoidmuscle

(D)Alongitslowerborder

1.Occipitalartery

2.HypoglossalnerveMohamed el fiky

Stylohyoid

Site: lies along the upper border of the posterior belly of

digastric

Origin : posterior surface of styloid process.

Insertion : body of the hyoid bone at its junction with and the

greater cornu.

Nervesupply:facialnerve

Actions:pullsthehyoidboneupwardsandbackwards

Note:itstendonisperforatedbytheintermediatetendonof

thedigastricmuscle

StylohyoidMuscle

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MylohyoidMuscleThe two mylohyoids form the floor the floor of the mouth (oral diaphragm). Origin : mylohyoid line of the mandible. Insertion: 1.Posterior one-fourth of fibers: into the body of the hyoid bone. 2. Anterior three – fourths of fibers : into the median raphe

which extends 3.from the symphysis menti to the hyoid bone

Nerve supply : mylohyoid nerve. Actions: 1. elevation of floor of the mouth in the first

stage of deglutition 2. depression of the mandible.3. elevation of the hyoid bone

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2- Muscles

3- Glands

4- Vessels1- SkinandFascia

Platysma

AnteriorBellyofDigastric

SubmandibularLymphNodesSuperficialPartofSubmandibularGland

SubmentalandMyelohyoidVessels

1- SuperficialRelationsofmylohyoid

1. anterior belly of digastric

2. superficial part of the submandibular salivary gland

3.mylohyoidnerveandvessels

4.submentalvesselsandlymphnodes.

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1- GlandsSublingualGlandDeepPartofSubmandibularGland

anditsDuct

2- Nerves

ligual Nerveand

SubmandibularGanglionHypoglossalNerve 3- Muscles Hyoglossus

GeniohyoidGenioglossusStyloglossus

2- DeepRelationsof mylohyoidb) Deep relations: 1) Hyoglossus muscle : with the

following structures intervening between it and the mylohyoid: a) Styloglossusmuscleb) Lingualnerveand

submandibularganglion.c) Submandibulargangliond) Deeppartof

submandibularglandanditsduct

e) Hypoglossalnerve:2)Genioglossusmuscle:anteriortothehyoglossus.3)Sublingualsalivarygland:onthelateralsurfaceofthegenioglossus

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Hyoglossus MuscleOrigin : body and greater cornu of the hyoid bone. Insertion : posterior half of the side of the tongue. Nerve supply : hypoglossal nerveActions : depression of the tongue.

(A) Superficial (lateral) relations: a. overlapped by the mylohyoid musclesb. structures intervening between the mylohyoid and hyolossus are as follows from above downwards 1.Styloglossus muscle 2.Lingual nerve 3.Submandibular ganglion : suspended from the lingual nerve by 4.two roots. 5.Deep part of submandibular gland and its duct. 6.Hypoglossal nerve and vena comitans hypoglossi. 7.Suprahyoid branch of the first part of lingual artery.

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4.Glossopharyngealnerve.

1.Genioglossusmuscle.2.Middleconstrictormuscle

ofpharynx.

6.Lingualartery.

5.Stylohyoidligament.

3.Inferiorlongitudinalmuscleofthetongue.

(B) Deep ( medial) relations of hyoglossus:

1- Genioglossus

2- Middle constrictor of pharynx

3- Glossopharyngeal nerve

4- Stylohyoid ligament

5- Lingual artery.

(C) Structures passing deep to

the posterior border of hyoglossus :

from above down are:

1. Glossopharyngeal nerve

2. stylohyoid ligament

3. lingual artery.

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Glosspharyngealnerve

Stylohyoidligament

Lingualartery

StructuresthatappearatthePosteriorBorder

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Geniohyoid Muscle

Origin : inferior genial tubercle

Insertion : anterior surface of the body of the hyoid bone

Nerve supply : C1 through the hypoglossal nerve.

Actions:

u Elevates the hyoid bone

v Depresses the mandible when the hyoid bone is fixed

Geniohyoid Muscle

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GenioglossusMuscle

Shape : fan – shaped ; forms the main bulk of the tongue.

Origin : from the superior genial tubercle of the mandible

Insertion : into the tongue.

Nerve supply : hypoglossal nerve.

Actions:

1. acting alone: pulls the tongue forwards to the

opposite side.

2. withitsfellowoftheopposite:protrudethetongue

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SubmandibularGlandSuperficialpart

Deeppart

Mylohyoidmuscle

Parotid

SubmandibularGland

Size : about the size of walnut

Parts: the gland is divided into 2 parts :

(A) Superficial part : is large and lies superficial to the

mylohyoid muscle

(B) Deep part : is small and lies deep to the mylohyoid

muscle.

The two parts are continuous with each other around the

posterior border of mylohyoid muscle.

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Superficialpart

DeeppartBody of Mandible

Mylohyoidmuscle

Facialartery

Facialvein

The superficial part of the submandibular gland Superficial part has has 3 surfaces a. Inferolateral b. Lateral c. Medial

1) Inferolateral surface : related to : a. Skin b. Platysmac. Cervical branch of the facial nerve d. Deep fasciae. Facial vein.f. Submandibular lymph node 2) Lateral surface : is related to : a. Submandibular fossa below the mylohyoid line.b. Insertion of medial pterygoid c. Facial artery.

3) Medial surface: Anterior part : is related to the mylohyoid muscle from which it is separated bythesubmentalvessels,mylohyoidnerveandvessels.Ø Posteriorpart:isrelatedtothehyoglossus musclefromwhichitisseparatedbythefollowingstructures:1- Stryloglossus muscle.2- Lingualnerveandsubmandibularganglion3- Hypoglossalnerve4- Suprahyoidartery.

Lingualnerve

Lingualartery

Lingualvein

Mylohyoidmuscle

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Hypoglossalnerve

Lingualnerve

DeepPartof

SubmandibularGland

Genioglossus

SublingualGland

DeepPartofTheSubmandibularGlandExtends forwards in the interval between the mylohyoid and the hyoglossusRelations: Laterally : mylohyoid muscle Medially:hyoglossus muscleAbove:lingualnerveandsubmandibularganglionBelow:hypoglossalnerve.

Submandibular duct: • Is about 5cm long • Emerges from the anterior end of the deep part of the gland• Runs forwards on the hyoglossus under cover of the

mylohyoid • It then runs between the sublingual gland and the

genioglossus muscle • where the lingual nerve crosses lateral and then hooks below

it opens in the floor of the mouth , on the summit of the sublingual papilla at the side of the frenulum of the tongue

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NerveSupplyoftheSubmandibularGlandNerve supply: 1. Sensory supply : from the lingual nerve.

2. Sympathetic : from the sympathetic plexus around the facial

artery

3. Parasympathetic (secretomotor): from the chorda

tympani branch of facial along the lingual nerve

Arterial supply: from the facial and lingual arteries

Venous drainage : into the common facial or lingual veins

Lymphatic drainage : into the submandibular lymph nodes

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FlooroftheMouth

MylohyoidMuscleDeepPartof

SubmandibularGland

GenioglossusLigual Nerve

SubmandibularDuct

SublingualSalivaryGland

Site : located in the floor of the mouth between the mucous membrane and the Mylohyoid muscle occupying the sublingual fossa of the mandible. Shape : almond – shaped Size:isthesmallestofthethreemainsalivaryglands,3to4gminweightRelations:Superiorly:mucousmembraneofthefloorofthemouthwhichisraisedbytheglandtoofformthesublingualfold.

Inferiorly:mylohyoidmuscleMedially:genioglossusmuscle,lingualnerveandsubmandibularductLaterally:sublingualfossaofthemandibleDucts: 8-20ductscomeoutoftheglandtoopenintothefloorofthemouthonthesummitofthesublingualfold.Arterialsupply:sublingualandsubmentalarteriesVenousdrainage:lingualandfacialveinsLymphaticdrainage:submentalandsubmandibularlymphnodesNervesupplysupply:sameasthatofthesubmandibulargland

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Hypoglossalnerve

Genioglossus

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TheLingualNerveCourse in the submandibular region :

Ø Runs on the lateral surface of the hyoglossus deep to the

mylohyoid muscle.

Ø Finally it passes between the genioglossus and the

sublingual gland. Here it hooks around the submandibular duct

and divides into branches.

Distribution : u Carries general senation from the anterioir two-thirds of the

tongue and the floor of the mouth.

v The chorda tympani branch of the facial nerve which is

secretomotor (parasympathetic) to the submandibular and

sublingual salivary gland and gustatory to the anterior 2/3 of the

tongue is also distributed through

ChordaTympani

InferiorAlveolarnerve

Lingualnerve

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MedialPterygoidMuscle

Lingualnerve

LateralPterygoidMuscle

StyloglossusMuscle

Lastmolartooth

SuperiorConstrictorofPharynx

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SubmandibularGanglion

SubmandibularGanglionSite : lies on the hyoglossus muscle where it is suspended from

the lingual nerve by two roots.

Roots : 1. Sensory root : from the lingual nerve (passes without relay).

2. Sympathetic root : from the plexus around the facial artery

(passes without relay).

3. Parasympathetic (motor) root:

• Thepreganglionicfibersarisefromthesuperiorsalivary

nucleusintheponsandpasssuccessivelythroughthefacial

nerve,chordatympaniandlingualnervestorelayinthe

ganglion.

• Thepostganglionicsecretomotor fiberssupplythe

submandibularandthesublingualglands.Mohamed el fiky

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