UNSW Embryology

Carnegie Stages Large Images

© Dr Mark Hill (2009)

Acknowledgements

Introduction

This current page has large images of Carnegie stage 7 to 23 of Human embryonic development organized as a table showing dates and features for each stage.

Stages are based on the external and/or internal morphological development of the embryo, and are not directly dependent on either age or size. The human embryonic period proper is divided into 23 Carnegie stages. Criteria beyond morphological features include age in days, number of somites present, and embryonic length. (about Carnegie) Note that images are not to scale and there is another Carnegie Stage page with smaller images and more details about each stage.

Carnegie Stage 3

Features:

Carnegie Stage 7

Features: embryonic disc, primitive node, primitive streak, primitive groove, yolk sac

(note there are 2 separate images if this stage)

Carnegie Stage 8

Features: embryonic disc, connecting stalk, yolk sac

Carnegie Stage 9

Features: neural plate, neural groove, primitive node, primitive streak, amnion, first pairs of somites, connecting stalk

(note there are 2 separate images if this stage)

Carnegie Stage 10

Features: rostral neuropore, neural folds in region of developing brain, neural tube, somites, caudal neuropore, remnant of amniotic sac

(note there are 2 separate images if this stage)

Carnegie Stage 11

Features: rostral neuropore closing, forebrain, neural tube in region of developing spinal cord, somites, caudal neuropore, connecting stalk, amnion

Carnegie Stage 12

(approx day 26, 27 somites)

Features:forebrain, site of lens placode, site of otic placode, stomodeum, 1st pharyngeal arch, 2nd pharyngeal arch, 3rdpharyngeal arch, heart prominence, somites

Carnegie Stage 13

(approx day 28)

Features: site of midbrain, lens placode, site of nasal placode, 1,2,3 pharyngeal arches, L. ventricular prominence of heart, L. atrial prominence of heart, umbilical cord, lower limb bud, mesonephric prominence, upper limb bud

Carnegie Stage 14

(approx day32)

Features: midbrain, nasal placode, lens pit, 1,2,3 pharyngeal arches, fourth ventricle of brain, 1st pharyngeal groove, heart prominence, cervical sinus, upper limb bud, mesonephric ridge, lower limb bud, umbilical cord

Carnegie Stage 15

Carnegie Stage 16

(approx day 40)

Features: eye showing retinal pigment, nasolacrimal groove, nasal pit, fourth ventricle of brain, umbilical cord, 1st and 2nd pharyngeal arches, cervical sinus, heart, developing arm with hand plate, foot plate

Carnegie Stage 17

(approx day 42)

Features: pigmented eye, nasal pit, nasolacrimal groove, external acoustic meatus, auricular hillock, heart, digital rays, liver pronminance, thigh, ankle, foot plate, umbilical cord

Carnegie Stage 18

(approx day 44)

Features: roof of hindbrain, eyelid, nasolacrimal groove, auricle,, external acoustic meatus, hand plate with digital rays

Carnegie Stage 19

(approx day 48)

Features: eyelid, eye, external acoustic meatus, auricle of external ear, digital ray, wrist, liver prominence,

Carnegie Stage 20

(approx day 51)

Features: scalp vascular plexus, eyelid, eye, nose, external acoustic meatus, auricle of external ear, arm, elbow, wrist, liver prominence, digital rays

Carnegie Stage 21

(approx day 52)

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

Carnegie Stage 22

(approx day 54)

Features: scalp vascular plexus, eyelid, eye, nose, auricle of external ear, arm, elbow, wrist, knee, toes separated, umbilical cord

Carnegie Stage 23

(approx day 56)

Features: scalp vascular plexus, eyelid, eye, nose, auricle of external ear, mouth, shoulder, arm, elbow, wrist, toes separated, sole of foot, umbilical cord

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