Tongue /prosthodontic courses

TONGUE
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INDIAN DENTAL ACADEMY
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• INTRODUCTION:
• Tongue is a muscular organ situated in floor of the mouth.
• it is associated with functions of taste, speech, swallowing,
and deglutition.
• DEVELOPMENT OF TONGUE:
• Tongue develops in relation to the pharyngeal arches in
the floor of the developing mouth in the 4th week of intra
uterine life.
• Each pharyngeal arches arises as a mesodermal thickening
in the lateral wall of the foregut and grows ventrally to
become continuous with the corresponding of the opposite
arch.
• The medial most part of the mandibular arches proliferate
to form two lingual swellings.

• The lingual swellings are partially separated from each other
by another swelling that appear in the midline- Tuberculum
impar.
• Immediately behind tuberculum impar the epithelium
proliferates to form downward growth -Thyroglossal
duct(thyroid gland develops)
• The site of this down growth is subsequently marked by a
depression called- Foramen caecum
• Another midline swelling is seen in relation to the medial
ends of 2nd ,3rd ,4th arches.
• The eminence soon shows a sub division into
• Cranial part- related to 2nd and 3rd arches,(copula)
• Caudal part- related to 4th arch(forms the epiglottis)

DEVELOPMENTOFTONGUE:

• Anterior 2/3rd of tongue:
• Formed by fusion of :
• Tuberculum impar and the two lingual swellings.
• Thus anterior 2/3rd derived from mandibular arch.
• Posterior 1/3rd of tongue:
• Is derived from cranial part of hypobrachial eminence
(copula).
• In this situation 2nd arch mesoderm gets buried below the
surface.
• The 3rd arch mesoderm grows over it to fuse mesoderm of
1st arch.
• The posterior 1/3rd of tongue is thus formed by 3rd arch
mesoderm.

DEVELOPMENT OF TONGUE

• Posterior most part of tongue:
• Is derived from 4th arch.
• Its embryological origin anterior 2/3rd of tongue is
supplied by:
• lingual branch of mandibular nerve.(post trematic
nerve of 1st arch)
• Posterior 1/3rd is supplied by:
• Glossopharyngeal nerve(nerve of 3rd arch)
• The most posterior part is supplied by:
• Superior laryngeal nerve(nerve of 4th arch)

• Musculature of tongue:
• Derived from occipital myotomes.
• Nerve supplied by hypoglossal nerve . It is a nerve of
myotomes.
• Epithelium of tongue:
• First made up of a single layer of cells , later it becomes
stratified and papillae becomes evident.
• Taste buds are formed in relation to terminal branches of
the innervating nerve fibers.

DEVELOPMENT OF TONGUE MUSCLES

Part of
tongue
Embryonic
part of which
derived
nerve supply
General
sensation
taste motor
Epithelium
over ant
2/3rd of
tongue
POst1/3 rd
of tongue
Post most
part
Muscle
First arch
3rd arch
4th arch
Occipital
myotomes
Lingual
branch of
man nerve
Glossopharyn
geal
Superior
laryngeal br.
Of vagus
Facial (chorda
tympani)
Glossopharyn
geal
Sup laryngeal
br .of vagus
Hypoglossal

o Tongue has two parts:
Oral part:
lies in the mouth
Pharyngeal part:
lies in the pharynx
oOral and pharyngeal parts are separated by v-shaped
sulcus -sulcus terminalis.

oExternal features:
o The tongue has-
A root
A tip
A body-1. Has curved upper surface or dorsum
2.inferior surface- confined to oral part
.

• The root:
• The root is attached to-
mandible and soft palate above
Hyoid bone below
• Because of these attachments we are not able to swallow
the tongue.
• The tip:
• Forms the anterior free end which at rest lies behind the
upper incisor teeth.

• The body:
• Dorsum of the tongue:
• Convex in all directions.
• Divided into:
1. oral part or anterior two third
2.Pharyngeal part or posterior one third
• Divided by v shaped groove sulcus terminalis.
• Two limbs of V meet at the median pit – FORAMEN
CAECUM
• It represents the site from which thyroid diverticulum
grows down in the embryo
• Oral and pharyngeal parts differ in development ,
topography, structure and function

DORSUM OF THE TONGUE:

• Oral part or papillary part:
• placed in the floor of the mouth , margins are free in
contact with gums and teeth.
• Superior part:
• shows median furrow and is covered with papillae
which make it rough.
• Inferior part:
• is covered with smooth mucous membrane , which
shows a median fold called the frenulum linguae.
• More laterally there is a fold – PLICA FIMBRIATA

• Pharyngeal or lymphoid part:
• Lies behind palatoglossal arches and sulcus terminalis.
• It forms the anterior wall of oropharynx .
• The mucous membrane has no papillae but has many
lymphoid follicles known as lingual tonsil.
• Posterior most part of tongue:
connected to epiglottis by 3 mucous membrane folds.
Median glosso epiglottic fold
Right glossoepiglottic fold
Left glossoepiglottic fold
On either side of median fold depression called- VALLECULA
Lateral folds separate the vallecula from piriform fossa.

• Muscles of tongue:
• A middle fibrous septum divides the tongue into right and
left halves.
• Each half contains four extrinsic and intrinsic muscles.
• Intrinsic muscles: Extrinsic muscles:
Superior longitudinal Genioglossus
Inferior longitudinal Hyoglossus
Transverse Styloglossus
Vertical Palatoglossus

• INTRINSIC MUSCLES:
occupy the upper part of tongue and are attached to sub
mucous fibrous layer and median fibrous septum.
They alter the shape of tongue.
Superior longitudinal:
Lies beneath the mucous membrane.
It shortens the tongue and makes its dorsum concave.
Inferior longitudinal:
Lying close to inferior surface of tongue b/n genioglossus
and hyoglossus.
Shortens the tongue and makes dorsum convex.

• Transverse muscle:
Extends from median septum to margin.
It makes tongue narrow and elongated.
• Vertical muscle:
Found at the border of tongue.
It makes the tongue broad and flattened.

INTRINSIC MUSCLES OF TONGUE:

EXTRINSIC MUSCLES:
Genioglossus:
Fan shaped muscle which forms the main bulk of tongue.
Origin Insertion Function
upper genial
tubercle of
mandible.
Upper fibres - tip of
tongue
Middle fibres- dorsum
Lower fibres -hyoid
bone
Upper fibres: retract
the tip
Middle fibres: depress
the tongue
Lower fibres ; pull the
posterior part of
tongue forwards thus
protrude the tongue
from mouth.

• HYOGLOSSUS:
origin insertion function
Greater cornua and
lateral part of body
of hyoid bone.
Side of tongue b/n
stylohyoid and
inferior longitudinal
muscle of tongue.
Depresses the
tongue makes
dorsum convex ,
retracts the
protruded tongue.

• STYLOGLOSSUS:
Tip and adjacent
part of anterior
surface of styloid
process.
Side of tongue
intermingling with
fibers of
hyoglossus.
During swallowing
it pulls the tongue
upwards and
backwards.

• PALATOGLOSSUS:
Oral surface of
palatine aponeurosis.
Side of tongue at the
junction of oral and
pharyngeal parts.
Pulls up the root of
tongue approximate
the palatoglossal
arches ,thus closes
the oropharyngeal
isthmus.

EXTRINSIC MUSCLES OF TONGUE:

• Arterial supply of tongue:
Chiefly from-
lingual artery branch of external carotid artery.
Roof of tongue also supplied by:
Tonsillar artery
Ascending pharyngeal artery

ARTERIAL SUPPLY OF TONGUE:

• Venous drainage of tongue:
• In to deep lingual vein ,it is principle vein of tongue.
• It is visible in the inferior surface of the tongue.

LYMPHATIC DRAINAGE:
Tip of the tongue-
Drains bilaterally to the submental lymph nodes.
The right and left parts of remaining halves of anterior 2/3rd of
tongue-
Drains into unilaterally to sub mandibular lymphnodes.
The posterior 1/3rd of the tongue –
Drains bilaterally to the jugulo omohyoid nodes. These
are known as Lymphnodes of tongue.

LYMPHATIC DRAINAGE OF THE TONGUE

NERVE SUPPLY:
MOTOR NERVE SUPPLY SENSORY NERVE SUPPLY
All intrinsic and extrinsic
muscles are supplied by
(except palatoglossus)-
Hypoglossal nerve
Palatoglossus – supplied by
cranial root of accessory
nerve through pharyngeal
plexus.
For anterior 2/3rd of tongue:
Lingual nerve- Is nerve of
general sensation
Chorda tympani- Nerve of
taste (except vallate papillae)
For posterior1/3rd of tongue:
Glossopharyngeal nerve for
both general sensation and
taste including circumvallate
papillae.
Posterior most part: supplied
by vagus nerve through
internal laryngeal branch.

Histology of tongue:
 The bulk of the tongue is made up of a striated muscles.
 The mucous membrane consists of layer of connective
tissue (corium), lined by stratified squamous epithelium .
• Taste buds are most numerous on the sides of vallate
papillae , and foliate papillae and posterior 1/3rd of tongue.
 There are no taste buds on the mid dorsal region of the
oral part of the tongue.

HISTOLOGY OF TONGUE:

• Functions of the tongue:
• Speech
• Mastication
• Deglutition
• Taste
• Digestion
• Jaw development
• Sucking
• General sensitivity

TASTE AND TASTE SENSATION:
 Taste is a sensation of flavour perceived in the mouth and
throat on contact with a substance.
 Taste is primary function of taste buds in the mouth , but
common experience that ones smell of smell contributes
strongly taste perception.
Primary sensations of taste:
Specific chemicals that excite different taste receptors are
still incomplete.
Some studies have identified 13 possible receptors in taste
cells:
2 sodium receptors, 1 chloride receptors, 1 adenosine
receptor, 1 inosine receptor, 2 sweet receptors, 2 bitter
receptors, 1 glutamate receptor , 1 hydrogen ion receptor.

• The receptor capabilities have been collected into 4 general
categories called primary sensation of taste.
• They are sour, salty, bitter, sweet.
Taste bud and function:
• The taste cells are continually being replaced by mitotic
division from surrounding epithelial cells so that young cells
and other mature cells that lie toward center of the bud
and soon break up and dissolve.
• The taste buds are small ovoid or barrel shaped
intraepithelial organs about 0.08mm in high, 0.04 in height.
• They extend from basal lamina to the surface epithelium.
•

• Their outer surface is almost covered by few flat epithelial
cells ,which surround small opening the taste pore.
• It leads into narrow space lined by supporting cells of the
taste bud.
• outer supporting cells are arranged like a staves of a barrel.
• Inner and shorter ones are spindle shaped .
• Between the latter are arranged 10 to 12 neuroepithelial
cells ,the receptors of taste stimuli.

• From the tip of each cell several microvilli or taste hairs
,protrude outward into the tastepore to approach the cavity
of the mouth.
• The microvilli provide the receptor surface for taste.
• Interwoven among the bodies of the taste cells in a branching
terminal network of a taste nerve fibers that are stimulated by
taste receptor cells.
• Many vesicles from beneath the cell membrane, these vesicles
contain a neurotransmitter substance that is released through
cell membrane to excite the nerve fiber findings in response
to taste stimulation.

Structure of taste bud

Structure of taste bud:

• The primary taste sensations that is sweet, salt, sour, bitter are
perceived in different regions of tongue and palate:
• Sweet: tip of the tongue
• Salt: lateral border of the tongue
• Bitter: Palate and middle posterior part of tongue
• Sour: palate and posterior lateral parts of tongue

Taste sensations:

• LOCATION OF TASTE BUDS:
• The body and the base of the tongue differ widely in the
structure and mucous membrane.
• The anterior part is termed as papillary part and
posterior part is called lymphatic part of dorsolingual
mucosa.
• Taste buds or located in inner side of papillae , posterior
surface of epiglottis.
• Types of papillae:
• Fungiform papillae
• Fili form papillae
• Foliate papillae
• Circum vallate papillae

• Filiform papillae:
• On the anterior part are found numerous fine-pointed ,
cone shaped papillae that gives rise to velvet like
appaerance.
• These projections , filiform papillae (threaded shaped
papillae),are epithelial structures containing a core of
epithelial connective tissue from which secondary papillae
protrude towards epithelium.
• The covering epithelium is keratinised .
• The filiform papillae do not contain taste buds.

• Fungiform papillae(mushroom-shaped):
• Interspersed between filiform papillae.
• They are round reddish prominences.
• Their colour is derived from rich capillary network visible
through the surface epitheium.
• Contains a few taste buds 1 to 3 found only on their dorsal
surface.

• Vallate or circumvallate papillae(walled):
• Infront of the dividing v shaped terminal sulcus b/n the
body and base of tongue , 8 to 10 vallate papillae .
• They do not protrude above the surface of tongue .
• On the lateral surface of vallate papillae epithelium
contains numerous taste buds.
• The ducts of small serous glands called von ebner glands
open into mouth.
• They may serve to wash out the soluble contents of
food and are main source of salivary lipase.
• Foliate papillae:
• located in lateral border of posterior surface of tongue.
• They contain taste buds.

Papillae of tongue

Type of taste papillae Type of taste carried Mediated nerve
Vallate papillae
Foliate papillae
Fungiform papillae(tip
of the tongue)
Fungiform
papillae(lateral borders)
Bitter taste
Sour taste
Sweet taste
Salt taste
Glossopharyngeal nerve
Glossopharyngeal nerve
Intermediofacial nerve by
chordatympani.
Intermediofacial nerve by
chordatympani.

Nerve supply of papillae:

ANAMOLIES OF TONGUE:
Developmental diseases of tongue:
Aglossia and microglossia
Macroglossia
Ankyloglossia
Median rhomboid glossitis
Benign migratory glossitis
Fissured tongue
Cleft tongue
Lingual thyroid nodule
Lingual varices
Hairy tongue

• Neurological diseases that affects the tongue:
Glossodynia
Dyskinesia
Paralysis
Premalignant lesions and conditions that affects the tongue:
Leukoplakia
Lichen planus
Oral sub mucous fibrosis
Malignant tumours that affects the tongue:
Squamous cell carcinoma
Malignant lymphoma
Malignant melanoma
Metastatic tumour
Sarcoma

• Heamartomatous lesions affecting the tongue:
• Hemangioma
• Lymphangioma

• Aglossia and microglossia:
• Aglossia is complete absence of tongue at birth.
• This malformation is very rare.

PICTURE OF AGLOSSIA

• Macroglossia:
• (tongue hypertrophy, enlarged tongue, prolapsus of tongue,
pseudomacroglossia)
• 1. True macroglossia
• 2. Pseudo macroglossia
True macroglossia :
Congenital causes , acquired causes
Congenital causes:
Idiopathic muscular hypertrophy
Gland hyperplasia
Haemangioma
Lymphangioma

Down syndrome
Beckwith – wiedemann syndrome
Lingual thyroid
Trisomy 22
Acquired causes:
Metabolic or endocrine:
Hypothyroidism, cretinism , Diabetis
Inflammatory:
Syphilis, Amebic desentary, Ludwigs angina,
pemphigus
Smallpox, TB ,Typhoid, Scurvy, pellagra

Systemic or medical conditions:
Myxedema
Hypertrophy
Acromegaly
Neurofibramatosis
Traumatic:
Surgery, trauma, radiation injury
Neoplastic:
carcinoma, lymphangioma , haemamgioma, lingual thyroid
Infiltrative:
Amyloidosis, sarcodiosis

Pseudo macroglossia:
Which force the tongue into abnormal position.
Habitual posturing of tongue
Enlarged tonsils or adenoids
low palate and decreased oral cavity volume displacing the
tongue
Retrognathism
Hypotonia of the tongue
Commonly associated syndromes are:
Downs syndrome
Beckwith- wiedemann syndrome

• Treatment:
• The goal of surgery is to return the patient to an
anatomically and functionally normal.

PICTURE OF MACROGLOSSIA:

Ankyloglossia or tongue- tie:
Inferior frenulum attaches to the bottom of the tongue
and subsequently restricts the free movement of tongue.
Types:
Partial: Short lingual frenum
Complete: fusion of tongue and floor of the mouth.
c/f:
Restricted tongue movement
Speech defects
Management:
Frenulectomy

PICTURE OF ANKYLOGLOSSIA(PARTIAL)

COMPLETEANKYLOGLOSSIA(FUSION OF THE
TONGUEAND FLOOR OF MOUTH)

Fissured tongue:
(scrotal tongue, lingua plicata)
Frequently seen.
Characterised by grooves that vary in depth are noted along
the dorsal and lateral surface.
Etiology: unknown
Polygenic mode of inheritence is suspected.
C/F:
Totally benign condition
Slight male predilection
Usually asymptomatic

Associated syndromes are:
Melkersson-Rosenthal syndrome:
Triad of:
Fissured tongue, chelitis granulomatosa, Bells palsy
Downs syndrome
Management:
No definitive treatment is necessary.

FISSURED TONGUE:

Medain rhomboid glossitis:
(central papillary atrophy, posterior lingual papillary atrophy)
Etiology:
o The posterior dorsal point of fusion is occasionally defective,
leaving a rhomboid shaped smooth erythematous area lacking a
papillae
C/f:
o presents in the posterior midline of the dorsum of tongue , just
anterior to v –shaped grouping of circumvallate papillae.
o male predilection.
o Is a focal area of susceptibility to chronic atrophic candidiasis.
o Commonly referred as KISSING LESION.
Treatment: No treatment necessary.
Anti-fungal therapy will reduce the clinical
erythema.

MEDIAN RHOMBOID GLOSSITIS

Benign migratory glossitis: (geographic tongue, wandering
rash of tongue):
 Is a form of psoriasiform mucositis of the dorsum of the
tongue.
 Constantly changing pattern of serpinginous white lines
surrounding areas of smooth depapillated mucosa.
 Depapillated areas of tongue have reminded others of
continental outlines of globe – hence the name geographic
tongue .
Treatment:
No treatment is necessary.
Symptomatic treatment with topical prednisolone.

BENIGN MIGRATORY GLOSSITIS

Hairy tongue:( Lingua nigra, Black hairy tongue)
• Hypertrophic filiform papillae.
• With lack of normal desquamation which may be extensive
and form athick matted layer on the dorsal surface.
• Colour may vary from yellow white to brown or even black.
• Etiology:
• Use of certain drugs
• Poor oral hygiene
• Fungal growrh

Black hairy tongue

SQUAMOUS CELL CARCINOMA OF THE
TONGUE

LICHEN PLANUS OF TONGUE:

Orolingual paraesthesia:
(Glossodynia or painful tongue , Glossopyrosis or burning
tongue) :
Etiology:
Deficiency states such as pernicious anemia and pellagra
Diabetis
Gastric disturbances such as hyperacidity and hypoacidity
psychogenic factors
Trigeminal neuralgia
Periodontal diseases
Xerostomia
Hypothyroidism
Angioneurotic edema
Moellers glossitis
Oral habits: tobbaco, spices,
Antibiotic therapy, Local dentures , irritating clasps

C/F:
Pain , burning sensation, itching
Management:
Topical anaesthetics
Analgesics
Anti bacterial and antifungal agents
Anti histamines
Vitamins

Atrophy of tongue papillae:
Causes:
Streptococcal infections
HIV infections
Candidiasis
Herpes infections
Cancer of the tongue
Trauma
Nutritional disorders like:
Vit b12 deficiency's(pernicious anemia)
Iron deficiency anemia
Folic acid deficiency – Pernicious anemia
vit b2 deficiency
Niacin deficiency(pellagra)
Diabetis
Pyridoxine deficiency

Also seen in:
Plummer vinsons syndrome
Vitamin c deficiency- scurvy
Chemotherapy :
anti- cancer drugs
Developmental :
Benign migratory glossitis
Mucocuteneous :
Atrophic lichen planus
OSMF
Scleroderma
Xerostomia

Ulcers on tongue:
Local causes:
Mechanical trauma
Chemical injury
Thermal injury
Recurrent apthous stomatitis
Infections:
Oral candidiasis
Malignant conditions:
Squamous cell carcinoma
Malignant melanoma
Irradiation

Systemic causes:
Auto immune diseases:
Bechets syndrome
Kawasaki disease
Lichen planus
Systemic lupus erythematosis
Discoid lupus erythematosis
Inflammatory conditions:
Erythema multiforme
Stevens Johnson's syndrome
Chrons disease
Reiter's syndrome

Infections:
Epstein bar virus
Hand foot and mouth disease
Herpes simplex virus 1 and 2
Varicella zoster virus
HIV
Bacterial:
TB, Syphilis, ANUG
Drugs:
chemotherapeutic agents
Miscellaneous:
Thrombocytopenic purpura, Chronic renal failure

Recurrent apthous stomatitis of tongue:

Bechet syndrome

Kawasaki disease

Reiter's syndrome

• Changes in colour of the tongue:
Central cyanosis: Bluish colour
Jaundice: Yellowish colour
Advanced uremia: Brown colour
Riboflavin deficiency: Megneta colour
Niacin deficiency: Bald tongue of sandwith, beefy red
Anemia- pale
Pernicious anemia- Beefy red(Hunter’s or Moeller’s glossitis)
Scarlet fever-Strawberry and Raspberry tongue

Scarlet fever

Lesions commonly occurring in the dorsal and
lateral surfaces:
Geographic lesion
Fissured lesion
traumatic ulcer
Recurrent apthous ulcer
Inflammatory hyperplasia
Hemangioma
Leukoplakia, speckled leukoplakia, erythroplakia
Lichen planus
Hairy tongue, SCC(lateral border)
Bald tongue- vitamin, iron defficiency
Syphilis+

Lesions commonly occurring on ventral surface of
tongue:
Ankyloglossia
Traumatic ulcer
Benign mesenchymal tumour
mucous retention phenomenon
SCC
Leukoplakia, erythroplakia

• Gauze piece and pressed between thumb and index fingure.
EXAMINATION OF TONGUE:

• REFERENCES:
B D Chaurasia’s HUMAN ANATOMY- 4TH EDITION
INDERBIR SINGH- HUMAN EMBRYOLOGY – 8TH EDITION
SHAFER’S ORAL PATHOLOGY- 5TH EDITION
ORBAN’S ORAL HISTOLOGY AND EMBRYOLOGY-13TH
EDITION
NORMAN K.WOOD , PAUL W.GOAZ- Differential
diagnosis of oral and maxillo facial lesions

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