Development and malformations of face and palate
Compiled by András Csillag and Andrea D. Székely GERMINAL LAYER DERIVATIVES
ECTODERM contributing to the formation of the face appears by the 4th week.
The oropharyngeal membrane (interface between ECTODERM and ENDODERM) is located in front of the later palatine tonsils. Ectodermal structures limiting the stomodeum participate in the formation of the face, as well as of the nasal and oral cavities.
MESENCHYME that fills the pharyngeal arches derives from the neural crest
ECTOMESENCHYME DEVELOPMENT OF THE FACE
WEEK 6 The face is formed by 5 processes approximately 24 days Frontonasal prominence (1) Maxillary prominence (2) 1st arch Mandibular prominence (2) nasal (olfactory) pits form surrounded by the medial and lateral nasal processes nasolacrimal groove separates the lateral nasal process from the maxillary process maxillary processes fuse with the medial nasal processes lateral nasal processes fuse with the maxillary processes, thus obliterating the nasolacrimal groove. DEVELOPMENT OF THE FACE 5-week embryo 6-week embryo 7-week embryo. 10-week embryo
The nasal prominences are gradually Maxillary prominences have fused separated from the maxillary with the medial nasal prominences. prominence by deep furrows. CEPHALIC PRIMORDIA - PLACODES
Olfactory placode
Pharyngeal Stomodeum” arches
Nasal placodes - thickenings of the surface ectoderm (later differentiate into the olfactory epithelium) DEVELOPMENT OF THE NASAL CAVITIES AND THE HARD PALATE By week 5 the placodes form the nasal pits. They further invaginate and the pits approach the primitive oral cavity.
A thin oronasal membrane separates the two cavities. By its rupture the primitive choanae will form DEVELOPMENT OF THE NASAL CAVITIES AND THE HARD PALATE
By week 8, a partition forms between the primitive nasal chambers and the oral cavity The primary palate - the anterior aspect derives from the intermaxillary segment (or median palatine process, formed by the medial nasal processes).
The secondary palate – the posterolateral aspect derives from the lateral palatine processes (a medial growth of the maxillary process). DEVELOPMENT OF THE NASAL CAVITIES AND THE HARD PALATE As the secondary palate is formed, the nasal septum grows inferiorly toward it. The nasal septum and the two palatine shelves unite to form separate right and left nasal chambers, an oral cavity, and the definitive choanae.
Pns T Lpp Concha Pns Lpp T M Lpp The tongue occupies the center of the stomodeum. The lateral palatine processes (palatal shelves) are located at the lateral borders of the tongue. The Meckel's cartilage, providing a template for the development of the mandible, is located at the base of the tongue.
The primitive nasal septum Septum
descends. By fusion the Concha hya Secondary palate palate separates the nasal
T cavity from the oral cavity. DEVELOPMENT OF THE NASAL CAVITIES AND THE HARD PALATE SUMMARY TABLE OF FACE DEVELOPMENT
Facial Primordia Adult Derivatives Frontonasal prominence forehead, nose, philtrum, (unpaired) primary palate
Maxillary prominence upper cheek, maxilla, (paired) zygomatic, lateral portion of upper lip, secondary palate
Mandibular prominence lower lip, lower cheek, (paired) mandible Head and neck
Week 5
Buccopharyngeal m. pharynx
stomodeum Week 5 Week 5 Week 5 - 6 Week 6 Week 6 Week 6 - 7 Week 7 - 8 Week 10 DEVELOPMENTAL MALFORMATIONS
unilateral cleft lip bilateral cleft lip involving jaw and involving jaw and primary palate primary palate
Supernumerary nostril
cleft secondary palate DEVELOPMENTAL MALFORMATIONS
Primary Lip Upper jaw palate
Philtrum Primary palate ANTERIOR FACE DEFORMITIES
Median cleft lip lower cleft lip oblique fissure
macrostomia microstomia ANTERIOR FACE DEFORMITIES
Cleft lip or palate: the medial nasal processes fail to fuse with the maxillary processes. May occur separately or in combined deformities.
Processus globularis Cleft palate (bilateral cleft lip associated and/or uvula: with bilateral cleft palate) the palatine shelves fail to fuse with each other and/or with the primary palate. MEDIAN CLEFT LIP BILATERAL CLEFT LIP COMBINED WITH CLEFT PALATE A cleft lip (cheiloschizis)
B bilateral cheilo-gnato-palatoschizis (processus globularis = intermaxillary segment)
C unilateral cheilognatopalatoschizis LATERAL FACE DEFORMITIES
Oblique facial cleft: the nasolacrimal duct remains exposed due to the lateral nasal process failing to fuse with the maxillary process. It may be combined with cleft lip.
Lateral cleft lip: macrostomia the maxillary and mandibular processes fail to fuse at the angle of the mouth. OBLIQUE FACIAL CLEFT Congenital craniofacial abnormalities
Macrocephaly • Proportionate • Disproportionate Microcephaly Pierre-Robin Craniosynostosis sequence • Sagittal • Coronal Eye anomalies • Hypertelorism • Hypotelorism • Coloboma • Microphthalmia • Anophthalmia Cleft palate and cleft lip • Syndromic (30 %) • Nonsyndromic (70 %) Micrognathia (small mandible) • Pierre-Robin sequence Agnathia Congenital ear malformations THERAPY
Cleft lip
Before surgery After surgery DEVELOPMENT OF THE EXTERNAL EAR
First pharyngeal cleft DERIVATIVES OF THE PHARYNGEAL ARCHES AND CLEFTS (ECTODERM)
pouch 1
cleft 1
cervical operculum cervical sinus DERIVATIVES OF THE PHARYNGEAL ARCHES AND POUCHES (ENDODERM) DERIVATIVES OF THE PHARYNGEAL ARCHES AND POUCHES (ENDODERM)
superior parathyroid (4th pouch) thyroid gland inferior parathyroid (3rd pouch)
thymus (3rd pouch) DEVELOPMENT OF THE THYROID GLAND
4th week anterior 2/3 of the tongue thyroid diverticulum
5th week foramen caecum thyroglossal duct thyroid DEVELOPMENTAL MALFORMATIONS
median cervical cyst
persisting thyreoglossal duct DEVELOPMENTAL MALFORMATIONS
lateral cervical cyst lateral cervical fistule