DEVELOPMENT OF FACE, NOSE AND

PALATE(Page 65)

Dr. Sherif Fahmy

Development of Face• Face is developed from 5 processes (prominences):• One fronto-nasal process, 2 maxillary processes and

2 mandibular processes.• Maxillary process is a foreward growth of dorsal

end if 1st pharyngeal arch.• Mandibular process is a forward growth of ventral

end of 1st pharyngeal arch.• These processes surround stmodeum (primitive

nasal and oral cavities). Bucco-pharyngeal membrane will rupture to allow continuity between oral and pharyngeal cavities.

Bucco-pharyngeal membrane

Cloacal membrane

Cardiogenic area

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Forebrain bulge

Pericardial bulge

Stomodeum

Bucco-pharyngeal membrane

Pharynx

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Dr. Sherif Fahmy

Maxillary process

Mandibular process

2nd arch

Stomodeum

Forebrain bulge

Fronto-nasal process

Maxillary process

Mandibular process

Stomodeum

Pericardial bulge

Fronto-nasal process

Differentiation & Fusion

Fronto-nasal process

Maxillary process

Mandibular process

Pericardial bulge

Stomodeum

Fronto-nasal process

Maxillary process

Mandibular process

Stomodeum

Pericardial bulge

Dr. Sherif Fahmy

Nasal placod

Stomodeum

Fronto-nasal process

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CleftMedial nasal prominence

Lateral nasal prominence

Nasal pit

Maxillary process

Developing eye

Fronto-nasal process

Mandibular process

Dr. Sherif Fahmy

Nasal pits

Cleft

Medial nasal prominence

Lateral nasal prominence

Maxillary process

Dr. Sherif Fahmy

Cleft

Medial nasal prominence

Lateral nasal prominence

Maxillary process

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Intermaxillary segment

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Intermaxillary segment

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Medial nasal prominence

Lateral nasal prominenece

Anterior nasal opening

Maxillary process

Mandibular process

Fronto-nasal process

Dr. Sherif Fahmy

Fronto-nasal Process• Nasal placode: rounded thickening in the

lower lateral parts of the fronto-nasal process.

• Nasal pits & prominences: invagination of placode will form nasal pits which are surrounded by medial & lateral nasal prominences (folds).

• Intermaxillary segment: from fused medial nasal prominences . It forms intermaxillary segments that form middle part of nose, filtrum, part of upper jaw that carries upper 4 incisors and primary palate.

Maxillary Process• It is separated from side of fronto-nasal

process by naso-lacrimal groove, inside which a cord of ectodermal cells is formed then becomes canalized to form naso-lacrimal duct. Its upper end forms lacrimal sac.

• Maxillary process fuses with fronto-nasal process covering naso-lacrimal duct.

• It forms lower boundary of nasal pit.• It is separated from other maxillary

process by intermaxillary segment.

-It also fuses partially with mandibular process to form the cheek.-Palatine process is formed as inward projection of maxillary process to form secondary palate which divides stomodeum into upper nasal and lower oral cavity.So maxillary process forms upper part of cheek, upper lip except filtrum, upper jaw except part that carries upper incisors and most of hard palate.

Mandibular Process• It forms lower part of cheek, whole lower lip

and lower jaw and floor of mouth.• Development of palate:• 1- Primary palate: from intermaxillary

segment of fronto-nasal process.• 2- Secondary palate: from palatine shelves of

maxillary processes that form most of hard palate and soft palate.

• -Hard palate receives downward growth of nasal septum.

Preimitive maxilla

Secondary maxilla

Dr. Sherif Fahmy

Palatine shelves

Nasal septum

Coronal Section

Primitive palate

Palatine shelves

Primary palate

Secondary palate

Medial nasal prominence

Lateral nasal prominenece

Anterior nasal opening

Maxillary process

Palatine process of maxilla (hard palate)

Mandibular process

Fronto-nasal process

Congenital Anomalies of Face & Palate• 1- Dermoid cyst: cystic swelling at line of fusions between

processes of the face.• 2- Oblique facial cleft: failure of fusion between maxillary

and fronto-nasal processes.• 2- Macrostomia or Microstomia : defective or marked

fusion between maxillary and mandibular processes.• 3- Cleft (hare) lip: cleft lip due to failure of fusion between

maxillary process and intermaxillary segment.• 4- Cleft palate: failure of fusion between different parts

that form palate. It could be:– A- Unilateral complete cleft palate.– B- Bilateral complete cleft palate.– C- Partial cleft palate.– D- Cleft uvula.

Dermoid cyst

Dr. Sherif Fahmy

Oblique facial celft

Bilateral cleft lip

MicrostomiaDr. Sherif Fahmy

Macrostomia

Unilateral cleft lip

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Unilateral complete cleft palate

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Bilateral complete cleft palate

Nasal septum

Partial (median) cleft palate

Unilateral partial cleft palate

Hare lip

Dr. Sherif Fahmy

Development of Mouth & Salivary glands• Mouth: It is developed from lower part of

stomodeum (below developed hard palate) and anterior part of foregut. Line of demarcation lies behind the gum.

• Salivary glands:– Parotid: from ectodermal outgrowth of buccal

mucosa. Its dorsal part gives several buds to form acini of the gland. Its ventral part is canalized to form the duct.

– Submandibular & sublingual: developed from endodermal buds from floor of mouth.