Development of face

1. Development of face and palate

2. • After formation of head fold , developing brain
& pericardium it forms two prominent
bulgings on ventral aspect embryo.
• these bulgings are seperated by
stomatodeum
• the floor of stomatodeum is formed by
buccopharyngeal membrane, which seperates
it from foregut.

4. • mesoderm covering developing forebrain
proliferates & forms a downward projection
that overlaps the upper part of
stomatodeum.---this projection called
frontonasal process.
• pharyngeal arches are laid down in lateral &
ventral walls of most cranial part of foregut
•

7. • face thus develops from—
• the frontonasal process
• first pharyngeal arch of each side(
mandibular arch)

9. • Human face development -begins - 4th week
of embryonic development.
• By 6th week external face is completed
• Incidence of congenital malformations of the
face is approximately 1 in 700 births

11. • Brain & heart bulging are
separated by stomatodaeum.
• floor of stomatodaeum is
formed by buccopharyngeal
membrane.
• mesoderm over developing
forebrain proliferates, &
projects downward
(frontonasal process) that
overlaps the upper part of
stomatodaeum.

12. • the mandibular arch gives off a bud from dorsal end –
maxillary process,
• it grows ventromedially cranial to main part of arch ---
mandibular process.
• the ectoderm overlying frontonasal process soon shows
bilateral localised thickenings , a little above stomatodeum
---nasal placodes.
• the placodes soon sink below the surface as nasal pits .
• the raised medial edge is called—medial nasal process,
• the raised lateral edge is called—lateral nasal process.

13. Face
• the mandibular processes of two sides grow
towards each other , & fuse in midline,
• thus it give rise to lower lip, lower jaw.
• each maxillary process now grows medially
and fuses first with the lateral then with
medial nasal process & then with each other .
Thus nasal pits are cut off from
stomatodeum .

14. • At the same time frontonasal process
becomes much narrower from side to side ,
as a result the two external nares come
closer.
•

15. • Maxillary prominences continue to increase in size & grows
medially compressing nasal prominence
Cleft b/w medial nasal prominence & maxillary prominence is
lost, and the two fuse
Upper lip is formed by two medial nasal prominences & two
maxillary prominences.
Lateral nasal prominences do not participate in formation of the
upper lip.
• Lower lip and jaw form from mandibular prominences that merge
across the midline.

16. • muscles of face are derived from mesoderm
of second branchial arch , therefore supplied
by facial nerve.

20. • Maxillary and lateral nasal prominences are
separated by a
deep furrow, nasolacrimal groove
• After canalization, cord forms the
nasolacrimal duct; its upper end widens to
form lacrimal sac.
• Maxillary prominences enlarge to form
cheeks and maxillae.

21. • nasal septum-
• Philtrum -Globular part of median nasal
swelling
• Upper lip- maxillary process+ frontonasal
process
• Lower lip- mandibular process

24. nose
• recieves contributions from frontonasal process , medial &
lateral nasal process of right & left sides .
• external nares are formed when nasal pits are cut off from
stomatodeum by fusion of maxillary process with medial
nasal process.
• frontonasal process becomes progressively narrower & its
deeper part forms nasal septum.
• mesoderm gets heaped up in centre to forms dorsum of
nose,
• groove appears b/w region of nose & bulging forebrain .
• as nose becomes prominent the external nares come to
open downwards instead of forwards.

25. Nasal cavity
• formed by extension of nasal pits .
• these pits are in open communication with
stomatodeum
• soon medial & laateral processes fuse &
forms partition b/w pit & stomatodeum ,
this is called primitive palate.( derived from
frontonasal process)
• nasal pits now deepen to form nasal sacs
which expand both dorsally & caudally .

26. • the dorsal part of this sac is ,at first
seperated from stomatodeumby a thin
buccopharangeal membrane .
• this membrane soon breaks down and thus
nasal sac has a ventral orifice tht opens on
the face (anterior nares / external nares) and
a dorsal orifice that opens into stomatodeum
( primitive posterior aperture)

27. • nasal cavities are seperated from mouth by
developing palate.
• lateral wall of nose is derived on each side
,from lateral nasal process.,conchae appear
as elevations on lateral wall of each nasal
cavity.

28. Anomalies
• there may be atresia of the cavity at the external nares
, or at posterior nasal aperture , can be unilateral or
bilateral
• rarely can be total absence of nasal passages.
• congenital defects in cribriform plate of ethmoid can
lead to communication b/w cranial cavity & nose.
• nasal septum may not be in midline ---deviated to one
side,
• nasal septum may be absent
• nasal cavity may communicate with mouth.

29. Development of palate

30. Development of Palate
The palate develops from two stages:
• Primary palate - 5th to 12th week
• Secondary palate
30

31. • From each maxillary process a plate like
shelf grows medially --palatal process
• thus ---
• two palatal process
• primitive palate from frontonasal process.

32. • definative palate is formed by fusion of these three
parts ---
• each palatal process fuses with posterior margin of
primitive palate.
• two palatal processes fuse with each other in
midline .this fusion begins anteriorly and procedes
backwards.
• Posterior 1/3rd of hard is also contributed by horizontal
plate of palatine bone .
• medial edge of palatal processes fuse with free
lower edge of nasal septum .thus seperating two
nasal cavities from each other and from mouth.

33. • at later stage mesoderm in palate
undergoes intramembranous ossification to
form hard palate .however ossification does
not extend into most posterior portion
,which remains as soft palate .
• the part of palate derived from frontonasal
process forms the premaxilla ---that carries
incissor teeth.

35. applied
• cleft palate
• defective fusion of various components of
palate give rise to cleft in the palate ,
• clefts of palate that extend to its anterior end
are associated with harelip , as both the upper
lip and the plate are formed by fusion of
maxillary process with frontonasal process
• clefts of palate result in anamoulous
communication between mouth and nose –
unilateral or bilateral.

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Prof. Makarem

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Prof. Makarem

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Prof. Makarem

42. Prof. Makarem 42

43. Thank you