Anatomy of Tongue And Its Applied Aspects

Presented by:Niti Sarawgi

Contents Introduction

Development of tongue

Anatomy of tongue

Parts and surfaces of the tongue Muscles of the tongue Vascular supply of the tongue Lymphatic drainage of the tongue Innervation of the tongue

Examination of the tongue

Clinical considerations and diseases of the tongue

Conclusion

References

Introduction

Pharyngeal part

Development of tongue Starts to develop near the end of the fourth week

Epithelium:

Anterior 2/3: from 2 lingual swellings and one tuberculum impar, i.e., from

first branchial arch supplied by lingual nerve (post-trematic) and chorda tympani

(pre-trematic) Posterior 1/3:

from the cranial half of the hypobranchial eminence, i.e., from the third arch

supplied by glossopharyngeal nerve

Posterior most:

from the fourth arch supplied by vagus nerve

Muscles develop from the occipital myotomes which are supplied by hypoglossal nerve

Connective tissue develops from local mesenchyme

Terminal sulcus

Hypobrachial eminence

Parts and surfaces of the tongueOral Part

• Apex• Dorsum part• Ventral part

Ventral surface  The thin strip of tissue that

runs vertically from the floor of the mouth to the undersurface of the tongue is called the lingual frenulum. It tends to limit the movement of the tongue.

On either side of frenulum there is a prominence produced by deep lingual veins. more laterally there is a fold called plica fimbriata

Glands of Blandin­Nuhn Anterior lingual glands (also called apical glands)

are deeply placed seromucous glands that are located near the tip of the tongue on each side of the frenulum linguae.

They are found on the under surface of the apex of the tongue, and are covered by a bundle of muscular fibers derived from the Styloglossus and Longitudinalis inferior.

They are between 12 to 25 mm. in length, and approximately 8 mm. wide, and each opens by three or four ducts on the under surface of the tongue's apex

Glands of Von­Ebner They are serous salivary glands

Located adjacent to the moats surrounding the circumvalate and foliate pappilae

Von Ebner's glands secrete lingual lipase

This secretion flushes material from the moat to enable the taste buds to respond rapidly to changing stimuli

Von Ebner's glands are innervated by cranial nerve IX, the glossopharyngeal nerve.

Gland of Weber

They lie along the lateral border of the tongue

These glands are pure mucous secreting glands.

These open into the crypts of the lingual tonsils on the posterior tongue dorsum.

Abscess formed due to accumulation of pus and fluids in this gland is called Peritonsillar Abscess

Lies behind the palatoglossal arches

Forms the anterior wall of the oropharynx

Devoid of papillae

Underlying lymphoid nodules embedded in the submucosa collectively called as lingual tonsils

Pharyngeal or Postsulcal PartEpiglottis

Lingual tonsil

Median epiglotic fold

Lateral epiglotic fold

valleculae

Palatine tonsil

Muscles of the tongue Intrinsic muscles

Superior longitudinal

Inferior longitudinal

Transverse

Vertical

Extrinsic muscles

Styloglossus

Hyoglossus

Genioglossus

Palatoglossus

Intrinsic muscles

GenioglossusGenioglossus

Arises from superior genial tubercle above the origin of geniohyoid

Hyoid bone

Insertion : the fibres radiate widely to be inserted into the mucous membrane of the tongue; the lowest fibres passing down to the hyoid body

Action Protrusion

Bilaterally –Central part depression

Unilaterally – Diverges to the Opposite side

HyoglossusHyoglossus

• Origin: greater cornu, front of body of hyoid bone• Insertion: side of the tongue between styloglossus and inferior

longitudinal ActionsActions

• Depresses the tongue

Chondroglossus 

A part of hyoglossus

Separated from it by genioglossus

Origin: medial side and base of lesser cornua

Insertion: intrinsic musculature between hyoglossus and genioglossus

StyloglossusStyloglossus

• Origin : styloid process near its apex

• Insertion : longitudinal part into the inferior longitudinal musclesOblique part into hyoglossus

• ActionAction• Draws the

tongue upwards and backward

hyoglossushyoglossus

styloglossusInferior longitudinal

musclesStyloid process

PalatoglossusPalatoglossus Origin: palatine

aponeurosis of soft palate

Insertion: side of the tongue

““more a part of soft palate than more a part of soft palate than the tonguethe tongue””

ActionAction: elevates the posterior part of the tongue

Bilaterally- approximates the palatoglossal folds to constrict the isthmus of the fauces

MUSCLES ORIGIN INSERTION ACTION(S)

GenioglossusUpper genial tubercle

of mandible

Upper fibres: tip of the tongue

Middle fibres: dorsumLower fibres: hyoid

bone

Upper fibres: retract the tip

Middle fibres: depress the tongue

Lower fibres: pull the posterior part forward(thus protrusion of the

tongue from the mouth)

HyoglossusGreater cornu, front

of lateral part of body of hyoid bone

Side of tongueDepress the tongue

Retracting the protruded tongue

StyloglossusTip, anterior surface

of styloid processSide of tongue

Pulls the tongue upwards and

backwards during swallowing

PalatoglossusOral surface of

palatine aponeurosis

Side of tongue (junction of oral and

pharygeal part)

Pulls up root of tongue, approximates palatoglossal arches, closes oropharyngeal

isthmus

Intrinsic muscles

Superior longitudinalSuperior longitudinal

• Origin: submucous fibrous layer below the dorsum of the tongue and lingual septum

• Insertion: extends to the lingual margin

• ActionAction• Turns the apex and sides of

the tongue upward to make the dorsum concave

Inferior longitudinalInferior longitudinal

• Narrow band close to the inferior surface of the tongue

• Origin: root of tongue and body of hyoid bone

• Insertion: apex of tongue

• ActionAction• Curls the tip inferiorly and

shortens the tongue

TransverseTransverse

• Origin: median fibrous septum

• Insertion: fibrous tissue at the margins of tongue

• ActionAction• Narrows and elongates the

tongue

VerticalVertical

• Origin: dorsum surface of the borders of the tongue

• Insertion: ventral surface of the borders of the tongue

• Action Action • Flattens and broadens the

tongue

Vascular supply of the tongueLingual arteryLingual artery

•A branch of external carotid artery(after passing deep to the hyoglossus muscles) •Divides into : •Dorsal lingual arteriesDorsal lingual arteries: supply posterior part •Deep lingual arteryDeep lingual artery : supplies the anterior part•Sublingual arterySublingual artery : supplies the sublingual gland and floor of the mouth

• Dorsal lingual vein-Dorsal lingual vein- drains the dorsum and sides of the tongue

• Deep lingual veinsDeep lingual veins (Ranine veins) - drains the tip of the tongue and join sublingual sublingual veinsveins from sublingual salivary gland

• All these veins terminate directly or indirectly into internal internal jugular veinsjugular veins

Lymphatic drainageLymphatic drainage Lymph from one side (esp. of the

posterior side), may reach the nodes of the both sides of the neck (in contrast to the blood supply which remains unilateral)

Tip - drain to submental nodes or directly to deep cervical nodes

Marginal lymphatics from the anterior part tend to drain to ipsilateral submandibular nodes or directly to inferior deep cervical nodes

Central lymphatics - drain to deep cervical nodes of either side

Posterior part - drains directly and bilaterally to deep cervical nodes

The deep cervical nodes usually involved: jugulodigastric and jugulo-omohyoid nodes

All lymph from the tongue is believed to eventually drain through the jugulo-omohyoid node before reaching the thoracic duct or right lymphatic duct

Innervation of the tongue

Nerve Supply Motor: all muscles of the tongue (intrinsic and extrinsic) are

supplied by hypoglossal nerve except palatoglossus which is supplied by pharyngeal plexus

Sensory:

anterior 2/3 of the tongue: general sensation: lingual nerve - branch of the

mandibular nerve (with cell bodies in the trigeminal ganglion)

taste: chorda tympani (with cell bodies in the geniculate ganglion of facial nerve)

parasympathetic secretomotor fibres to the anterior lingual gland run in the chorda tympani from the superior salivary nucleus, and relay in the submandibular genglion

posterior 1/3 of the tongue: innervated by the glossopharyngeal nerve (both general sensation and taste), with cell bodies in the glossopharyngeal ganglia in the jugular foramen

posterior most part of the tongue: innervated by the vagus nerve through the internal laryngeal branch (with cell bodies in the inferior vagal ganglion)

HISTOLOGY OF TONGUE 

Mucous Membrane on Ventral Surface It is thin, smooth and

loosely attached to the underlying Connective Tissue

It is freely mobile and not raised into papillae because epithelium is closely adherent to underlying muscle by a thin lamina propria.

It is covered with non- keratinized stratified squamous epithelium.

.

Mucous Membrane On Dorsal Surface  The dorsal surface Of the

tongue is covered with a mucous membrane, which is firmly adherent to the underlying C.T.

It is raised into small projections similar to the villi, but known as papillae (limited only to anterior 2/3ra of tongue).

The stratified squamous epithelium covering the dorsal surface of the tongue is mostly keratinized

Papillae of tongueThey are 4 varieties

Filiform

Fungiform

Foliate

Circumvallate

Filiform papillaFiliform papilla 

• Minute, conical, cylindrical projections which cover most of the presulcul dorsal area.

• Increase the friction between the tongue and food

• They bear many secondary papillae which are more pointed than those of vallate and fungiform papillae and covered with keratin

Fungiform papillaFungiform papilla

Located mainly on the lingual margin

Differ from filiform because are larger, rounded and deep red in colour

Bears one or more taste buds on its apical surface

These are mushroom shaped, more numerous near tip & margins of tongue but some of them scattered over the dorsum

Foliate papillaFoliate papilla

Red leaf-like mucosal ridges

Bilaterally at the sides of the tongue near sulcus terminalis

Bear numerous taste buds

Circumvallate papillaCircumvallate papilla Large cylindrical structures

8 to 12 in number

Form a ‘V’ shaped row in front of sulcus terminalis on the dorsal surface of the tongue

The entire structure is covered with squamous epithelium, in both sulcal walls & taste buds around

Special sensory innervation of the tongueSpecial sensory innervation of the tongue

Taste budsTaste buds

• Present in relation to cirumvallate papilla, fungiform papillae and foliate papilla

• Also present on the soft palate, the epiglottis, the palatoglossal arches, and the posterior wall of the oropharynx

Neuroepithelial taste cells or gustatory cells in taste buds:

They are modified columnar elongated cells which act as receptors. They have darkly-stained' elongated central nuclei. The superficial part of these cells is provided with short hairs (hairlets or microvilli). These hairlets project into the taste pore. The base of the taste cells is surrounded by sensory nerve fibres, carry the impulses of taste sensation to the brain.

Supporting cells in taste buds : They are elongated columnar cells with dark cytoplasm but lightly-stained nuclei. They form the outer wall of the taste bud. They have long microvilli that extend from their surfaces into the taste pore.

Basal cells are present at the base of the taste bud. They act as stem cells for renewal of taste cells and supporting cells.

Taste discrimination Gustatory receptors detect

four main types of taste sensation

Sweet: tip

Sour: middle

Salty: anterolateral

Bitter: base

However recent evidence indicates that all areas of tongue are responsive to all taste stimuli

Clinical examination of tongue

• InspectionInspection

• The tongue is examined for:The tongue is examined for:

ColourColour Swelling Ulcer Coating Size variation Distribution of filiform and fungiform papilla Crenations Fissures Atrophy or hypertrophy of papilla

Frenal attachment and deviations as patient moves out the tongue

Palpation

Gently palpate the muscles of the tongue

Clinical considerationsInjury to hypoglossal nerveInjury to hypoglossal nerve

• Trauma like fractured mandible may injure hypoglossal nerve • Paralysis ,atrophy of one side of tongue• Tongue deviates to paralyzed side during protrusion due to action

of unaffected genioglossus muscles • Others

infranuclear lesion (i.e., in motor neuron disease and in syringobulbia): gradual atrophy and muscular twitchings of the affected half of the tongue observed

supranuclear lesion (i.e., in pesudobulbar palsy): produce paralysis without palsy (tongue is stiff, small and moves sluggishly)

Paralysis of genioglossus muscleParalysis of genioglossus muscle

• Muscle tends to fall backward, obstructing airway• Total relaxation of genioglossus occur during general

anaesthesia so airway is inserted to prevent tongue from relapsing

Sublingual absorption of drugsSublingual absorption of drugs

• For quick absorption, pill or spray is put under the tongue where it dissolves and enter the lingual veins (nirtroglycerin in angina pectoris)

The presence of rich network of lymphatics and loose areolar tissue in the substance of tongue is responsible for enormous swelling of tongue in acute glossitis

The undersurface of the tongue is a good site for observation of jaundice

Carcinoma of Tongue is quite common. The affected side of the tongue is removed along with all the deep cervical lymph nodes

Carcinoma of posterior 1/3 of the tongue is more dangerous due to bilateral lymphatic spread

In unconscious patients , the tongue may fall and obstruct the airway.

In grand mal epilepsy, the tongue is commonly bitten by the front incisors during the attack

Diseases of the tongue Inherited, congenital, and developmental anomalies

Disorders of the lingual mucosa

Diseases affecting the body of the tongue

Malignant tumors of the tongue

Inherited, congenital, and developmental anomalies

Variation in morphology

Ankyloglossia Fissured tongue Macroglossia Hypoglossia Lingual thyroid and thyroglossal duct

Partial ankyloglossia (tongue­tie)Partial ankyloglossia (tongue­tie)

• Tongue tie can be classified as:

• Milder formMilder form: do not influence jaw development, tooth position or phonation

• Severe formSevere form: exhibit Midline mandibular diastema, periodontal defects• Extreme formExtreme form: complete

attachment of tongue to the floor of the mouth or alveolar gingiva

Microglossia (hypoglossia)Microglossia (hypoglossia)  Uncommon developmental condition of unknown origin

characterized by abnormally small tongue Entire tongue may be missing (aglossia) length of the mandibular arch will be smaller due to the

smaller size of the tongue.

    MacroglossiaMacroglossia 

Fissured, plicated, or scrotal tongueFissured, plicated, or scrotal tongue

  Lingual thyroid Lingual thyroid 

Proliferation of floor of pharyngeal wall 4th week

Descends

the neck anterior to trachea and larynx 7th week

Pathophysiology of lingual thyroid

Disorders of lingual mucosa• Geographic tongueGeographic tongue

• Hairy tongueHairy tongue

• Nonkeratotic and keratotic white lesionsNonkeratotic and keratotic white lesions– Candidiasis– Leukoplakia, hairy leukoplakia

• Nutritional defficiencies and hematologic Nutritional defficiencies and hematologic abnormalitiesabnormalities– Vitamin B12 deficiency– Iron deficiency anemia

• InfectionsInfections– Tertiary syphilis

Geographic tongueGeographic tongue::• Psoriasiform mucositis of the dorsum

of the tongue

• Prevalence is 1% to 2%

• Irregular reddish areas of depapillation

• thinning of the dorsal tongue epithelium usually surrounded by a narrow zone of regenerating papillae -whiter than the surrounding tongue surface

Hairy tongueHairy tongue

CandidiasisCandidiasis (Moniliasis)• Most common intraoral oppertunistic fungal infection • Causative agent: Candida albicans• Factors determining the clinical evidence of candidiasis: Immune status of the host Oral mucosal enviroment Strains of Candida

LeukoplakiaLeukoplakia

Pernicious anemiaPernicious anemia• Most common forms of vitamin

B12 deficiency

Clinical featuresClinical features

• Beefy red tongueBeefy red tongue• Erythematous areas on tip and

margins• De-papilation• Candidal infection

Iron deficiency anemiaIron deficiency anemia• Most common form of anemia found in 50% females

Plummer­Vinson syndromePlummer­Vinson syndrome

Also known as Paterson Kelly Syndrome

• Clinical featuresClinical features• Microcytic hypochromic anemia• Smooth and sore tongue• Angular chelitis• Spoon shaped nails

Disorders of lingual mucosaDisorders of lingual mucosa

Tertiary syphilis and Tertiary syphilis and interstitial glossitisinterstitial glossitis

• Tongue may be affected by gumma formation

• Non-ulcerating, irregular • indurations • Asymmetric pattern of grooves• Leukoplakia

Blandin and Nuhn mucocele The Blandin and Nuhn

mucocele occurs exclusively on the anterior ventral surface of the tongue at the midline.

Although the lesions may have clinical features similar to those of the mucocele, which is found elsewhere they tend to be more polypoid with a pedunculated base

Because of repeated trauma against the lower teeth, the surface may be red and granular or white and keratotic.

Malignant tumors Of Tongue           Malignant tumors Of Tongue                 

Squamous cell carcinoma

Squamous cell carcinoma of the tongueSquamous cell carcinoma of the tongue

Most common intraoral site

60% of lesions arise from the anterior 2/3rd of the tongue

The affected side of the tongue is removed surgically.

All the deep cervical lymph nodes are also removed, i.e. block dissection of neck.

Unilateral block dissection of the neck should be efficacious for early carcinoma of the lateral border of the tongue but because of the bilateral lymphatic drainage bilateral dissection should be performed if the tip of the tongue, the frenulum ,or the dorsum of the tongue is involved.

CONCLUSION

• ReferencesReferences B.D Chaurasia(2006) Human Anatomy,Regional and

Applied,Dissection.

Henry Gray(2004),Gray's Anatomy .

Neelima Anil Malik, Textbook of Oral and Maxillofacial Surgery.

Frank H.Netter,MD. Atlas of human anatomy.

William Henry Hollinshead. Anatomy for Surgeons: The head and neck

T.W. Sadler ,Langman’s Medical Embryology

Internet source.