Face Embryology

Dr Mark Hill

2013 Australian Chapter, American Academy of Craniofacial Pain (AACP) Meeting May 18 May 2013

Draft Page - notice removed when complete.

Introduction

This page will be updated and contain the final conference presentation.

Development of the Face

This animation shows a ventral view of development of the human face from approximately week 5 through to neonate.

The separate embryonic components that contribute to the face have been colour coded.

Frontonasal Prominence central portion (white)
Frontonasal Prominence - Lateral nasal (purple)
Frontonasal Prominence - Medial nasal (green)
Pharyngeal Arch 1 - Maxillary prominence (yellow)
Pharyngeal Arch 1 - Mandibular prominence (orange)
Stomodeum (black)

The stomodeum is the primordial mouth region and a surface central depression lying between the forebrain bulge and the heart bulge. At the floor of the stomodeum indentation is the buccopharyngeal membrane (oral membrane).

Note the complex origin of the maxillary region (upper jaw) requiring the fusion of several embryonic elements, abnormalities of this process lead to cleft lip and cleft palate.

Key Concepts

Pharyngeal Arches

Arch Cartilages

Meckel's cartilage - located within the first pharyngeal arch mandibular prominence, forms a cartilage "template" besides which the mandible develops by the process of intramembranous ossification. It is important to note that this cartilage template does not ossify (endochondral ossification) but provides a transient structure where the mandible will form, and later degenerates.

Week 3

Gestational Age (GA week 5)

These images of the Stage 11 embryo show the breakdown of the buccopharyngeal membrane.

Low power ventral view of the Buccopharyngeal Membrane
Higher power ventrolateral view of the Buccopharyngeal Membrane
Close up view of the degenerating Buccopharyngeal Membrane

Week 4 to 5

Gestational Age (GA week 6 to 7)

Stage 14 (week 5)

Begins week 4 centered around stomodeum, external depression at oral membrane

5 initial primordia from neural crest mesenchyme (week 4)

single frontonasal prominence (FNP) - forms forehead, nose dorsum and apex
- nasal placodes develop later bilateral, pushed medially
paired maxillary prominences - form upper cheek and upper lip
paired mandibular prominences - lower cheek, chin and lower lip

Stage 11 (25 days)
Stage 12 (26 days)
Stage 13 (28 days)
Stage 14 (32 days)

Week 6 to 7

Gestational Age (GA week 8 to 9)

<mediaplayer width='320' height='420' image="http://embryology.med.unsw.edu.au/embryology/images/9/9c/Stage16-18_face_02.jpg">File:Stage16to18 face 01.mp4</mediaplayer>

Movie shows a quick animation of the ventral views of the human embryo face, between Carnegie stage 16 to stage 18 (Week 6 to Week 7). Animation based on Kyoto embryos.

Note the initial prominence of the pharyngeal arches and nasal region. Then the development of the midline frontonasal region and the relative shifting of the nasal region from lateral to anterior location on to the developing face.

Links: MP4 version | Quicktime version | Lecture - Head Development | Movies

Week 5 to 8

Gestational Age (GA week 7 to 10)

<mediaplayer width='380' height='400' image="http://embryology.med.unsw.edu.au/embryology/images/9/92/Stage15to22_head_icon.jpg">File:Stage15to22 head 01.mp4</mediaplayer>

Movie shows a quick animation of the lateral view of the human embryo head, between Carnegie stage 15 to stage 22 (Week 5 to Week 8). Note that these stage images are not to scale.

Links: MP4 version | Face Development Movie | Lecture - Head Development | Movies

Week 9

Gestational Age (GA week 11)

Secondary Palate Development

<mediaplayer width='350' height='350' image="http://embryology.med.unsw.edu.au/embryology/images/4/4f/Palate_001_icon.jpg">File:Palate_001.mp4</mediaplayer>

Animation shows an inferior view of the developmental sequence of secondary palate formation. The lower jaw has been removed and the view shows the roof of the oral cavity and the maxilla (upper jaw) and lip.

Animation shows the left and right maxillary processes of the first pharyngeal arch.
Primary palate formation is the fusion of these maxillary processes with the frontonasal prominence (FNP) in the midline.
- Frontonasal prominence (FNP) contributing midline component of the upper jaw as well as the the philtrum of the upper lip.
Secondary palate formation is the growth of the palatal shelves towards the midline.

<mediaplayer width='350' height='350' image="http://embryology.med.unsw.edu.au/embryology/images/a/a3/Palate_002_icon.jpg">File:Palate_002.mp4</mediaplayer>

Animation shows an anterior view of the developmental sequence of secondary palate formation. The frontal region of the head has been removed to show the changes within the oral cavity.

Secondary palate formation is the growth of the palatal shelves towards the midline, from top to bottom:

frontonasal prominence - (FNP) midline forming nasal septum separating nasal cavities.
left and right nasal cavities - showing developing conchae and cartilage.
first pharyngeal arch maxillary processes - (palatal shelves) left and right growing towards midline and elevating above the tongue.
oral cavity - developing from the pharynx.
tongue - developing from the pharyngeal arches.

Week 12

Gestational Age (GA week 14)

Sagittal unlabeled
Sagittal labeled
Sagittal medial view
Sagittal lateral view
Pituitary unlabeled
Pituitary labeled
Tongue

Week 14

Gestational Age (GA week 16)

Growth of Head Structures

Maxilla

First pharyngeal arch - upper maxillary (pair) and lower mandibular prominences
Late embryonic period - maxillary prominences fuse with frontonasal prominence forming upper jaw (maxilla and upper lip)

Week 5 Stage 16
Week 6 Stage 17
Week 6.5 Stage 18
Week 7 Stage 19

EM Links: Image - stage 16 | Image - stage 17 | Image - stage 18 | Image - stage 19 | Palate Development

Temporal Bone and Mandible

Image shows growth of both bones from the end of the embryonic period (week 8) through the fetal period of development (to 9 months).

Inner Ear

Adult hearing embryonic origins

Week 5

Week 8

Stage 13 embryo (week 5) showing otocyst that will form the inner ear.

left Ventrolateral view of the whole embryo with 5-mm scale bar. At this stage of development no middle or external ear structures are apparent and will be derived later from pharyngeal arches one and two (labeled). The gray bar through the head indicates the plane of cross-section (right).

right A cross-section of the head showing the size and position of the otic vesicles. At this stage of development they lie within the head mesenchyme behind pharyngeal arch one and two and in close apposition to the developing hindbrain. Note the close position of the otic vesicle to the rhombomeres, hindbrain folds that represent the initial segmentation of the hindbrain. Also shown are developing cranial ganglia and blood vessel lying adjacent to the otic vesicles. The wall of the otic vesicle at this stage is a simple epithelium.

Stage 22 embryo (week 8) showing the embryo near the end of the embryonic period.

A. Lateral view of the whole embryo with 5 mm scale bar. Note the well developed external ear with simplified adult structure and narrower meatal opening. The grey bar through the head indicates the plane of cross-section for (B) and (C).

B. Cross-section of the head at the plane of the skull base and oral cavity to the top. The otic capsule is well formed by this stage containing all the membranous labyrinth structures. It is still a cartilaginous structure ventral to the brainstem and lying behind the oral cavity. The tongue occupies the floor of the oral cavity with the unfused palatal shelves lying lateral and the auditory tubes clearly shown on the posterior wall. The external ear is visible on the right hand side of the head with a band of cartilage (dark stain) within the auricle.

C. The gray box indicates this region: detail of inner and middle ear development. The middle ear cavity has not yet formed and the ossicles (malleus shown) are embedded in mesenchyme that is being lost. The tensor tympani muscle is differentiating in the adjacent mesenchyme. The inner ear membranous labyrinth has formed its adult external structure. The section through the turns of the cochlear duct shows the internal cochlea structure is still underdeveloped; in contrast, the balance region is more developed.

External Ear

Images of the lateral view of the human embryonic head from week 5 (stage 14) through to week 8 (stage 23) showing development of the auricular hillocks that will form the external ear.

The adult ear is also shown indicating the part of the ear that each hillock contributes.

Images are not to scale.

Head Growth

Movies

‎‎Face Development

Page | Play

‎‎Palate (oral view)

Page | Play

‎‎Palate (front view)

Page | Play

‎‎Tongue

Page | Play

‎‎Mandible Growth

Page | Play

Histology


Medial view	Lateral view

Historic Head Embryology
1910 Skull \| 1910 Skull Images \| 1912 Nasolacrimal Duct \| 1921 Human Brain Vascular \| 1923 Head Subcutaneous Plexus \| 1919 21mm Embryo Skull \| 1920 Human Embryo Head Size \| 1921 43 mm Fetal Skull \| Historic Disclaimer