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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.