Embryology of tongue and developmental disturbances

2.  What is Tongue?
Largest single muscular organ inside
the oral cavity, which lies relatively free.
Tongue develops in relation to the
pharyngeal arches.
it develops from two parts, they are
1. formation of anterior 2/3rd of the tongue
2. formation of posterior 1/3rd of the tongue

3.  Tuberculum Impar; first a
swelling arises in the middle
of the mandibular process.
And is flanked by two other
swellings
 Lingual swelling; The lateral
part of the mandibular
process mesenchymal
thickening develops to form
two lingual swellings.
 Swellings merges with each
other and forms mucous
membrane of ant 2/3rd of the
tongue.

4.  These lateral swelling quickly enlarge and
merge with each other and the tuberculum
impar to form a large mass from which
mucous membrane of the anterior 2/3rd of
the tongue is formed.
 Anterior 2/3rd is supplied by trigeminal
nerve.

5.  Root of the tongue arises
from large midline
swelling develops from
mesenchyme of 2nd, 3rd,
and 4th arches. Consists of,
 1. copula (associated with
2nd arch)
 2. A large hyobrachial
eminence (associated by 3,
4th arch)

6.  Hypobrachial eminence overgrows the
copula
 The tongue separates from the floor of the
mouth by a down growth of ectoderm
around its periphery, whish degenerates to
form lingual sulcus and gives the tongue
mobility.
 Post 1/3rd is supplied by glossopharyngeal
nerve.

7.  Muscle of the tongue
have a different orgin,
they arises from the
occipital somites, which
have migrated forward in
to the tongue area,
carrying with them their
nerve supply hypoglossal
nerve.

8.  Microglossia
 Macroglossia
 Ankyloglossia
 Cleft tongue
 Fissured tongue

9.  It is a rare congenital anomaly manifested by
the presence of Rudimentary or small tongue
 The condition when tongue being completely
absent is known as aglossia
 Patient finds difficulties in eating and
swallowing

10. CLASSIFICATION
I. True Microglossia
II. Relative Microglossia
TREATMENT
I. Orthognathic correction
II. Speech & language development

12.  It is a condition when patient have an enlarged
tongue
 May be congenital or acquired
ETIOLOGY FOR CONGENITAL MACROGLOSSIA
 Congenital Macroglossia is due to an over
development of the musculature
 Down syndrome
 Beckwith-Wiedemann syndrome

14.  Noisy breathing
 Difficulty with chewing/swallowing
 Drooling
 Slurred speech
 Widened interdental space
 Scalloping/crenations
 Open bite/mandibular prognathism
 Dry/cracked tongue

15.  Surgical reduction or trimming may be required
when Macroglossia disturbs the oropharyngeal
function

16.  It can be defined as a developmental condition
characterized by fixation of tongue to the floor
of the mouth, causing restricted movement
 It can be either complete Ankyloglossia or
partial Ankyloglossia (tongue tie)

17. Partial Ankyloglossia occurs as a result of short
lingual frenum or due to a frenum which
attaches too near to the tip of the tongue
Complete Ankyloglossia occurs as a result of
fusion between the tongue and the floor of the
mouth

18. CLINICAL FEATURES
 speech disorders
 deformities in dental occlusion
 Difficulties in swallowing
TREATMENT
 Partial Ankyloglossia are self corrective
 Complete Ankyloglossia can be surgically
treated by frenulectomy

20.  A complete cleft tongue occurs due to lack of
merging of lateral lingual swellings of this organ
 partially cleft tongue occurs more common and
is manifested as deep groove in the midline of
dorsal surface
 Partial cleft tongue occurs due to incomplete
merging and failure of groove obliteration by
underlying mesenchymal proliferation
 food debris and microorganisms collect in base
of cleft and cause irritation

22.  Its a malformation manifested clinically by
numerous small grooves on dorsal surface
radiation out from central groove along the
midline of tongue
ETIOLOGY
 It also occurs as a sequel to geographic tongue
 Hereditary factors

23. › Grooves / furrows – 2-6mm
› Asymptomatic / mild burning sensation rarely
› Melkerson Rosenthal syndrome
Chelitis granulomatosa, facial paralysis, scrotal
tongue

24.  The lesions are usually asymptomatic unless
debris is entrapped within the fissure and
causes irritation
 Fissured tongue affects the dorsum surface and
often extends to the lateral borders of the
tongue and form lobules