Theiler Staging

Question 1

TS 1

Answer 1

One-cell egg

Question 2

TS2

Answer 2

Dividing egg (2-4 cells)

Question 3

TS3

Answer 3

Morula

Question 4

TS4

Answer 4

Blastocyst (ICM apparent, 16-40 cells)

Question 5

TS5

Answer 5

Blastocyst (zona-free)

Question 6

TS6

Answer 6

Attachment of blastocyst

Question 7

TS7

Answer 7

Implantation and formation of egg cylinder

Question 8

TS8

Answer 8

Differentiation of egg cylinder

Question 9

TS9

Answer 9

First sign of radial symmetry - pre-streak and early streak

Question 10

TS10

Answer 10

Appearance of mid streak, late streak (no bud), late streak (early bud)

Question 11

TS11

Answer 11

Neural plate, Late neural plate, Early head fold, late head fold

Question 12

TS12

Answer 12

First appearance of somites

Question 13

TS13

Answer 13

Turning of the embryo

Question 14

TS14

Answer 14

Formation and closure of anterior neuropore

Question 15

TS15

Answer 15

Formation of posterior neuropore

Question 16

TS16

Answer 16

Posterior neuropore closes

Question 17

TS17

Answer 17

Deep lens indentation

Question 18

TS18

Answer 18

Closure of lens vesicle

Question 19

TS19

Answer 19

Lens vesicle completely separated from the surface epithelium

Question 20

TS20

Answer 20

Earliest sign of fingers (splayed-out)

Question 21

TS21

Answer 21

Anterior footplate indented

Question 22

TS22

Answer 22

Fingers separate distally

Question 23

TS23

Answer 23

Fingers & Toes separate

Question 24

TS24

Answer 24

Repositioning of umbilical hernia

Question 25

TS25

Answer 25

Skin wrinkled

Question 26

TS26

Answer 26

Long whiskers

Question 27

TS27

Answer 27

Newborn mouse