The tongue is a muscular organ in the mouth that aids in tasting, speaking, chewing, and swallowing. It has intrinsic and extrinsic muscles that allow it to move and change shape. The tongue's surface contains papillae that give it a rough texture and help with taste. The root of the tongue attaches to bones in the mouth, while the tip is free. Sensory nerves allow the tongue to detect different tastes across its surface.

1. SIDHARTHA MANGAL BORDOLOI

2.  The tongue is the muscular organ situated in the
floor of the mouth.
FUNCTIONS
 It is associated with the function of -:
i. Taste
ii. Speech
iii. Mastication
iv. Deglutition

3. The tongue has:
1. ROOT
 Attached to the mandible and hyoid bone by fibres of
Genioglossus and Hyoglossus muscles.
 Because of these attachments we are not able to swallow the
tongue itself.
2. TIP
 Tip of tongue forms its anterior free end, which at rest, lies
behind the upper incisor teeth.
3. BODY
 Has (a) curved upper surface or dorsum.
(b) an inferior or ventral surface.

4. DORSUM OF TONGUE
 Convex in all directions.
 Divided into
(a) oral or papillary,
(b) pharyngeal or lymphoid
part.
 These two parts are
differentiated by a faint V-
shaped groove, the sulcus
terminalis.
 The two limbs of ‘V’ meet at a
median pit, named the
foramen caecum, from where
they run laterally and
forwards up to the
palatoglossal arches.

5.  The foramen caecum represents the site from
which the thyroid diverticulum grows down
into the embryo.
 The oral and pharyngeal parts of the tongue
differ in their development, topography,
structure, and function.

6. ORAL or PAPILLARY PART
 Lies on the floor of the mouth.
 Its margins are free and in contact with the gums and
teeth. The palatoglossal fold merges with these
margins at the junction of anterior 2/3 with posterior
1/3.
 Just in front of the palatoglossal arch each margin
shows 4 to 5 vertical folds, named the foliate papillae.
 The superior surface of oral part shows a median
furrow and is covered with papillae which make it
rough.

7. PAPILLAE OF THE TONGUE
 These are projections of mucous membrane or corium which
gives the anterior two- third of the tongue its characteristic
roughness. These are of following four types:
1. Vallate or Circumvallate papillae:
 They are largest in size 1-2 mm in diameter and are 8-12 in
number.
 They are situated immediately in front of the sulcus terminalis
in a single row.
 Each papilla is a cylindrical projection surrounded by a circular
sulcus.
 The wall of the papilla are raised above the surface.

8. 2. Fungiform Papillae
 Numerous near the tip and margins of the
tongue, but some of them are also scattered over
the dorsum.
 These are smaller than vallate papillae but larger
than filiform papillae.
 Each papilla consists of the narrow pedicle and a
large rounded head.
 They are distinguished by their bright red colour.

9. 3. Filiform papillae
 Covers most of the presulcal area of the
dorsum of the tongue , and gives a
characteristic velvety appearance. Contains no
taste buds.
 They are smallest and most numerous of the
lingual papillae.
 Each is pointed and covered with keratin; the
apex is often split into filamentous processes.
4. Foliate papillae
 These are present as 4 to 5 vertically arranged
mucous folds on the lateral margins of the
tongue, in front of the sulcus terminalis.

10. PHARYNGEAL or LYMPHOID PART
 Lies behind the palatoglossal arches and sulcus terminalis.
 Its posterior surface some times called the base of the tongue, forms the
anterior wall of oropharynx.
 The mucous membrane has no papillae, but has many lymphoid follicles
that collectively constitute the lingual tonsils.
 Mucous glands are also present.
 Posteriormost part of the tongue is connected to the epiglottis by three
folds of mucous membrane.
 These are the median glossoepiglottic fold and right and left lateral
glossoepiglottic folds.
 On either sides of median folds there is a depression called the vallecula.
 The lateral folds separate the vallecula from the piriform fossa.

11. INFERIOR or VENTRAL SURFACE
 Lined by a thin mucous membrane which gets reflected on the floor
of the mouth. It does not contain papillae.
 A median fold of mucous membrane connecting the tongue to the
floor of mouth called as the frenulum linguae.
 On either side of frenulum linguae there is a prominence produced
by the deep lingual veins. The lingual nerve and artery lie medial to
the veins on each sides but are not visible.
 More laterally to the lingual veins, there is a fold called plica
fimbriata that is directed forwards and medially towards the tip of
the tongue.
 Sublingual papilla is present on each side of the base of frenulum
linguae as an elevation which has the opening of the duct of
submandibular gland at its summit.

12.  A middle
fibrous
septum
divides the
tongue into
right and
left halves.
Each half
contains
four
intrinsic and
extrinsic
muscle.

13. INTRINSIC
MUSCLES
 Occupy the upper
part of the
tongue, and are
attached to the
submucous
fibrous layer and
to the median
fibrous septum.
They alter the
shape of the
tongue.

14. 1. Superior longitudinal muscle.
 Lies beneath the mucous membrane.
 It shortens the tongue and make its dorsum concave.
2. Inferior longitudinal muscle.
 is a narrow band lying close to the inferior surface of the
tongue between the genioglossus and hyoglossus.
 It shortens the tongue and makes its dorsum convex.
3. Transverse muscles
 Extends from the median septum to the margins.
 It makes the tongue narrow and elongated.
4. Vertical muscle
 Present at the borders of the anterior part of the tongue.
 It makes the tongue broad and flattened.

15. EXTRINSIC MUSCLE
 Connects the
tongue to the
mandible via
genioglossus; to
the hyoid bone
via hyoglossus;
to the styloid
process via
styloglossus; and
to the palate via
palatoglossus.

16. 1. Genioglossus
 Fan shaped muscle which forms the main
bulk of the tongue.
 Arises from the upper genial tubercle of the
mandible, from where the fibres fan out and
run backwards.
 The upper fibres are inserted into the tip,
the middle fibres into the dorsum, and the
lower fibres into the hyoid bone.
 The upper fibres retract the tip, the middle
fibres depress the tongue, and the lower
fibres pull the posterior part of the tongue
forwards and thus protrudes the tongue
from the mouth.
 This muscle if paralysed, the tongue will fall
back on the oropharynx and block the air
passage.

17. 2. Hyoglossus
 Thin quadrant muscle.
 Arises from the whole
length of greater cornu and
lateral part of the body of
hyoid bone.
 The fibres run upwards and
forwards to insert on the
side of the tongue between
styloglossus and inferior
longitudinal muscle of the
tongue.
 Depresses the side of the
tongue, makes the dorsum
convex and retracts the
protruded tongue.

18. 3. Styloglossus
 Arises from the tip and adjacent part of
the anterior surface of the styloid process
as well as from the upper end of the
stylohyoid ligament.
 It passes downwards and forwards and
inserted into the side of the tongue.
 During swallowing, it pulls the tongue
upwards and backwards.

19. 4. Palatoglossus
 Originates from the oral
surface of palatine
aponeurosis.
 It lies under the
palatoglossal arch and
inserts into the side of
tongue at the junction of
its oral and pharyngeal
parts.
 Pulls up the root of the
tongue, approximates the
palatoglossal arches, and
thus decreases the width
of oropharyngeal isthmus.

20.  Chiefly
derived
from the
lingual
artery.
 The root of
the tongue
is also
supplied by
the tonsillar
and
ascending
pharyngeal
arteries.

21.  The arrngement of the veins of the tongue is
variable.
 Two venae comitantes accompany the lingual artery
and one vena comitantes accompanies the
hypoglossal nerve.
 The deep lingual vein is the largest and principal vein
of the tongue. It is visible on the ventral surface of
the tongue. It runs backwards and crosses the
genioglossus and the hyoglossus below the
hypoglossal nerve.
 These veins unite at the posterior border of the
hyoglossus to form the lingual vein which ends either
in the common facial vein or in the internal jugular
vein.

23.  The tip of the tongue drains bilaterally to the
submental lymph nodes.
 The right and left halves of the remaining part
of the ant. 2/3 of the tongue drain unilaterally
to the submandibular lymph nodes.
 The posterior 1/3 of the tongue drains
bilaterally to the jugulo-omohyoid lymph nodes.

25. MOTOR NERVES
 All the intrinsic and
extrinsic muscles, except
the palatoglossus, are
supplied by the hypoglossal
nerve.
 The palatoglossus is
supplied by the cranial root
of the spinal accessory
nerve through the
pharyngeal plexus.

26. SENSORY NERVES
 The lingual nerve is the nerve of general sensation.
 Chorda tympani is the nerve of taste for the
anterior 2/3 of the tongue except vallate papillae.
 The glossopharyngeal nerve is the nerve for both
general sensation and taste for the posterior 1/3 of
the tongue including the circumvallate papillae.
 The posteriormost part of the tongue is supplied
by the vagus nerve through the internal laryngeal
branches.

28. 1. Epithelium
 Anterior two-third
 From two lingual swellings and one tubercular impar.
 The tubercular impar soon disappears.
 This part is supplied by the nerve of first pharyngeal arch
i.e. lingual and chorda tympani nerve.
 Posterior one third
 From cranial part of the hypoglossal eminence, i.e. from the
third arch. Therefore, it is supplied by the glossopharyngeal
nerve.
 Posteriormost part
 From the fourth arch, therefore, supplied by internal
laryngeal branch of the vagus nerve.

31. 2. Muscles
 The muscles develop from the occipital
myotomes which are supplied by
hypoglossal nerve.
3. Connective tissue
 Develops from local mesenchyme.

32.  Four established tastes are:
1. Sweet- at the tip of the
tongue (fungiform papillae).
2. Sour- along the edges of the
tongue.
3. Salt- on the dorsum of the
tongue.
4. Bitter- on the back of the
tongue.
5. Recently ,umami a 5th taste
sense,dominant taste of
food containing L-
glutamate, has been added.

33.  Also calles as gustatory caliculi or organ.
 Found in the tongue,soft palate,epiglottis,and the
posterior wall of the oral part of pharynx.
 Most common on the vallate papilla of tongue.
 About 50 to 150 taste cells found in a taste bud.
 Single taste cell restricated to only single type of
receptor.
 Taste buds have 3 types of cells;
a.Supporting cells,
b.Sensory cells and
c.Basal cells.
Taste bud has a pore that opens out to surface of
tongue.
Life span of taste buds is 10 to 14 days.

35.  Microvilli present on the taste cells act as receptor for taste.
 The taste sensation is then transferred to the nerve fibres woven
around the body of the taste cells.
 Taste impulses from the anterior 2/3rd of the tongue pass first into
lingual nerve then by the chorda tympani finally into the tractus
solitarius in the brain stem.
 Sensation from the circumvallate papillae and from other posterior
regions of the mouth and throat transmitted through the IX cranial
nerve and goes into the tractus solitaries.
 All taste fibers synapse in the posterior brain stem in the nuclei of the
tractus solitarious.
 These nuclei send second order neurons to a small area of ventral
posterior medial nucleus of the thalamus.
 From the thalamus third order neurons are transmitted to the cerebral
cortex.

37.  The under surface of the tongue is a good
site along with the bulbar conjunctiva for
observation of jaundice.
 In infranuclear lesion of the hypoglossal
nerve, there is gradual atrophy of the
affected half of the tongue or hemiatrophy,
while supranuclear lesions of the
hypoglossal nerve produces paralysis.

38.  Microglossia
 Presence of small or rudimentary tongue.
 Macroglossia
 Causes displacement of the teeth and malocclusion.
 Congenital macroglossia is due to an over development of the
musculature, which may or may not be associated with
generalized muscular hypertrophy.
 Congenital macroglossia can be seen in..
congenital hypothyroidism
down’s syndrome
Beckwith’s hypoglycemic syndrome.
 Secondary macroglossia may occur as a result of tumor of the
tongue, such as a diffuse lymphangioma or hemangioma,
neurofibromatosis, cretinism, acromegaly and in amylodoisis.

39.  Ankyloglossia
 Complete ankyloglossia occurs as a
result of fusion between tongue and
floor of mouth.
 Partial ankyloglossia or common
tongue tie occurs as a result of
short lingual frenum or frenum
attached too near the tip of the
tongue.
 Patient exhibits with speech
difficulties.
 Commonly associated with Pierre
robin syndrome.

40.  Cleft Tongue
 A rare condition.
 Due to lack of merging of the lateral lingual
swellings of tongue.
 Partial cleft tongue is more common than
complete.
 Also found as one feature of the oro-facial-digital
syndrome.
 Fissured tongue
 A malformation manifested clinically by
numerous small furrows or grooves on the
dorsal surface .

41.  Median Rhomboid Glossitis
 Congenital abnormality, due to failure
of the tubercular impar to retract or
withdraw before fusion of the lateral
halves of the tongue, so the structure
devoid of papillae is interposed
between them.
 Clinically appears as an ovoid-,
diamond-, or rhomboid-shaped
reddish patch or plaque on the dorsal
surface of the tongue immediately
anterior to the circumvallate papillae.

42.  Benign Migratory Glossitis
 Unknown etiology.
 May be related to emotional stress.
 Male to female ratio is 1:2.
 Shows multiple areas of desquamation of the filiform papillae of
tongue in an irregular pattern.
 Central portion of the lesion sometimes appears inflamed, while the
border may be outlined by a thin, yellowish-white line or band.
 The areas of desquamation remains for a short time at one location
and heal and appear in other location.

43.  Hairy Tongue
 Unusual condition
 Characterized by hypertrophy of the filiform papillae
with lack of normal desquamation which may be
extensive and form a thick matted layer on the
dorsal surface.
 The colour of the papillae may vary from yellowish
to brown or even black.
 Associated with immunodefecient status includind
AIDS.

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