Carnegie stage 21

Introduction

Facts

Week 8, 53 - 54 days, 22 - 24 mm

Events

Ectoderm: sensory placodes, nasal pits moved ventrally, fourth ventricle of brain

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 digital rays begin to separate, wrist, hand plate with webbed digits

Features

scalp vascular plexus, eylid, eye, nose, auricle of external ear, arm, elbow, wrist, knee, notch between digital rays, umbilical cord

Identify: straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, scalp vascular plexus, webbed digits, liver prominance, thigh, ankle, foot plate, umbilical cord

Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline

Kyoto Collection

View: This is a dorsolateral view of embryo. Amniotic membrane removed.

Image source: Embryology page Created: 19.03.1999

Image source: The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota and Prof. Shigehito Yamada, Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan for educational purposes only and cannot be reproduced electronically or in writing without permission.