ANAT2341 Lab 6 - Late Embryo

From Embryology
Lab 6: Introduction | Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Online Assessment

Primary Palate

Stage16-18 face.jpgBailey140.jpg

Above images show face development through week 6 to week 7 (1mm scale markings).

The animation shows the early fusion of the primary palate in the human embryo between stage 17 and 18, going from an epithelial seam to the mesenchymal bridge.

<html5media height="500" width="420">File:Face_001.mp4</html5media>

Click Here to play on mobile device

Development of the Face

Face 001 icon.jpg

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.

See also the movie anterior face movie showing a similar view of human embryo faces between Carnegie stage 16 to 18.

Links: MP4 version | Animated GIF | Lecture - Head Development | Head Development | Movies

Stage18 em11.jpg

Week 8

Stage 22 image 159.jpg Stage 22 image 103.jpg

Stage 22 image 159.jpg Selected Head Images: B4 - Choroid Plexus | B5 - Cochlea | B6 - Cochlea


The dark "pear-shaped" central structure at the top is the developing tongue. The two pale regions either side are the palatal shelves, note that they have not yet fused in the midline (failure of this process is cleft palate).

Stage23 embryo oral cavity 04.jpg

Week 8 Hard palate development


Behind that a pale cartilagenous region (that later ossifies) encloses the structuctures of the inner ear, beside which middle ear bones are forming. On the righthand side of the head the external ear is visible. The lower half of the image shows the developing brainstem with a large ventricular space occupied in part by an extensive choroid plexus (manufacturer of cerebrospinal fluid).

Embryonic External Ear

Shown below are the changes in external ear development between week 5 to week 8. Development changes from a series of 6 hillocks on arch 1 and arch 2 (week 5) to a structure resembling the adult ear (week 8).

External ear stages-14-23-adult.jpg

Lab 6: Introduction | Trilaminar Embryo | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Online Assessment

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Cite this page: Hill, M.A. (2024, May 24) Embryology ANAT2341 Lab 6 - Late Embryo. Retrieved from

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G