UNSW Embryology

Carnegie Stage 22

© Dr Mark Hill (2008)

Acknowledgements

	Carnegie Stage 22 Facts: Week 8, 54 - 56 days, 23 - 28 mm View: Lateral view. Amniotic membrane removed. Identify: straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, ear auricle, scalp vascular plexus, separated digits (fingers), thigh, ankle, umbilical cord

Events

Ectoderm:

Mesoderm: heart prominence, ossification continues

Head: nose, eye, external acoustic meatus

Body:straightening of trunk, heart, liver, umbilical cord

Limb: upper limbs longer and bent at elbow, foot plate with webbed digits, wrist, hand plate with separated digits

Next- Carnegie Stages 23

Stage 23 Unlabelled | Stage 23 Labelled

Glossary of Terms

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S |T | U | V | W | X | Y | Z

Student Study - Stage 22 selected sections

The series of selected stage 22 Human embryo cross-section images below are to illustrate internal features in different anatomical regions at this stage.

Students should use these images to identify tissue and organ development features not visible on the surface of the embryo.

Clicking the image will open the original cross-section image page.

Note that there is a full set of stage 22 embryo cross-sections and additional highpower images showing specific organ and tissue features of this stage available on the Serial Sections page.

Anatomical Region

Head | Shoulder | Chest | Abdomen | Hip

Stage 22 Head

Note: developing brainstem, inner ear (cochlear), unfused palatal shelves

Stage 22 Shoulder

Note: musculoskeletal system, neural (spinal cord, dorsal root ganglia, sympathetic ganglia), trachea, oesophagus

Stage 22 Chest Region

Note: heart, lungs, vasculature

Stage 22 Abdomen Region

Note: Gastrointestinal organs (liver, stomach, herniated midgut, pancreas), urogenital organs

Stage 22 Hip Region

Note: Musculoskeletal structures (acetabulum, vertebral body, femur, developing skeletal muscles), urogenital organs

Carnegie Stage images

The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota for tutorial/revision purposes and cannot be reproduced electronically or in writing without permission.

UNSW Embryology ISBN: 978 0 7334 2609 4

UNSW CRICOS Provider Code No. 00098G