Talk:Carnegie Stages: Difference between revisions

From Embryology
 
(24 intermediate revisions by 2 users not shown)
Line 1: Line 1:


== Carnegie Stage Table ==
== Carnegie Stage Table 1==


{| width="100%" border="1"
{| border="0"
| width="30" |
| width="40" |
<center>'''Stage'''</center>
| width="65" |
<center>'''Days''' (approx)</center>
| width="101" |
<center>'''Size'''</center> <center>(mm)</center>
| width="100" |
<center>'''Images<br />'''(not to scale)</center>
| width="400" |
<center>'''Events'''</center>
|-
| width="40" |
<center>'''1'''</center>
| width="65" |
<center> 1 </center>('''week 1''')
| width="101" |
<center>0.1 - 0.15</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_zygote_two_pronuclei_02.jpg|60px|Link=Carnegie_stage_1]]</center>
| width="400" |
fertilized oocyte, pronuclei
|-
| width="40" |
<center>'''2'''</center>
| width="65" |
<center> 2 - 3</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_3.jpg|60px|Link=Carnegie_stage_2]]</center>
| width="400" |
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
|-
| width="40" |
<center>'''3'''</center>
| width="65" |
<center> 4 - 5</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_5.jpg|60px|Link=Carnegie_stage_3]]</center>
| width="400" |
loss of zona pellucida, free blastocyst
|-
| width="40" |
<center>'''4'''</center>
| width="65" |
<center> 5 - 6</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
 
| width="400" |
attaching blastocyst
|-
| width="40" |
<center>'''5'''</center>
| width="65" |
<center> 7 - 12<br /> ('''week 2''')</center>
| width="101" |
<center> 0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
 
| width="400" |
implantation
|-
| width="40" |
<center>'''6'''</center>
| width="65" |
<center> 13 - 15</center>
| width="101" |
<center> 0.2</center>
| width="100" bgcolor="#000000" |
 
| width="400" |
extraembryonic mesoderm, primitive streak
|-
| width="40" |
<center>'''7'''</center>
| width="65" |
<center> 15 - 17 </center><center>('''week 3''')</center>
| width="101" |
<center> 0.4</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage7_features.jpg|60px|Link=Carnegie_stage_7]]</center>
| width="400" |
gastrulation, notochordal process
|-
| width="40" |
<center>'''8'''</center>
| width="65" |
<center> 17 - 19</center>
| width="101" |
<center> 1.0 - 1.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage8_bf4.jpg|60px|Link=Carnegie_stage_8]]</center>
| width="400" |
primitive pit, notochordal canal
|-
| width="40" |
<center>'''9'''</center>
| width="65" |
<center> 19 - 21</center>
| width="101" |
<center> 1.5 - 2.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage9_dorsal.jpg|60px|Link=Carnegie_stage_9]]</center>
| width="400" |
'''Somite Number 1 - 3''' neural folds, cardiac primordium, head fold
|-
| width="40" |
<center>'''10'''</center>
| width="65" |
<center> 22 - 23 </center><center>('''week 4''')</center>
| width="101" |
<center> 2 - 3.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_10]]</center>
| width="400" |
'''Somite Number 4 - 12''' neural fold fuses
|-
| width="40" |
<center>'''11'''</center>
| width="65" |
<center> 23 - 26</center>
| width="101" |
<center> 2.5 - 4.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage11 bf7b.jpg|60px|Link=Carnegie_stage_11]]</center>
| width="400" |
'''Somite Number 13 - 20''' rostral neuropore closes
|-
| width="40" |
<center>'''12'''</center>
| width="65" |
<center> 26 - 30</center>
| width="101" |
<center> 3 - 5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage12 bf5b.jpg|60px|Link=Carnegie_stage_12]]</center>
| width="400" |
'''Somite Number 21 - 29''' caudal neuropore closes
|-
| width="40" |
<center>'''13'''</center>
| width="65" |
<center> 28 - 32 </center>('''week 5''')
| width="101" |
<center> 4 - 6</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage13 bf2c.jpg|60px|Link=Carnegie_stage_13]]</center>
| width="400" |
'''Somite Number 30''' leg buds, lens placode, pharyngeal arches
|- bgcolor="#CCFFCC"
| colspan="5" width="376" height="18" |
<center> [[Carnegie_stage_13_-_serial_sections|Stage 13/14 shown in serial embryo sections]] series of Embryology Program</center>
|-
| width="40" |
<center>'''14'''</center>
| width="65" |
<center> 31 - 35</center>
| width="101" |
<center> 5 - 7</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage14_bf2c.jpg|60px|Link=Carnegie_stage_14]]</center>
| width="400" |
lens pit, optic cup
|-
| width="40" |
<center>'''15'''</center>
| width="65" |
<center> 35 - 38</center>
| width="101" |
<center> 7 - 9</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage15 bf1c.jpg|60px|Link=Carnegie_stage_15]]</center>
| width="400" |
lens vesicle, nasal pit, hand plate
|-
| width="40" |
<center>'''16'''</center>
| width="65" |
<center> 37 - 42 </center>('''week 6''')
| width="101" |
<center> 8 - 11</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage16 bf1c.jpg|60px|Link=Carnegie_stage_16]]</center>
| width="400" |
nasal pits moved ventrally, auricular hillocks, foot plate
|-
| width="40" |
<center>'''17'''</center>
| width="65" |
<center> 42 - 101</center>
| width="101" |
<center> 11 - 14</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage17 bf1c.jpg|60px|Link=Carnegie_stage_17]]</center>
| width="400" |
finger rays
|-
| width="40" |
<center>'''18'''</center>
| width="65" |
<center> 101 - 48 </center>('''week 7''')
| width="101" |
<center> 13 - 17</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage18 bf1c.jpg|60px|Link=Carnegie_stage_18]]</center>
| width="400" |
ossification commences
|-
| width="40" |
<center>'''19'''</center>
| width="65" |
<center> 48 - 51</center>
| width="101" |
<center> 16 - 18</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage19 bf1c.jpg|60px|Link=Carnegie_stage_19]]</center>
| width="400" |
straightening of trunk
|-
| width="40" |
<center>'''20'''</center>
| width="65" |
<center> 51 - 53 </center>('''week 8''')
| width="101" |
<center> 18 - 22</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage20 bf1c.jpg|60px|Link=Carnegie_stage_20]]</center>
| width="400" |
upper limbs longer and bent at elbow
|-
| width="40" |
<center>'''21'''</center>
| width="65" |
<center>53 - 54</center>
| width="101" |
<center>22 - 24</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage21 bf1c.jpg|60px|Link=Carnegie_stage_21]]</center>
| width="400" |
hands and feet turned inward
|- bgcolor="#FFCCCC"
| colspan="5" width="376" |
<center> [[Carnegie_stage_22_-_serial_sections|Stage 22 shown in serial embryo sections series]] of Embryology Program</center>
|-
| width="40" |
<center>'''22'''</center>
| width="65" |
<center> 54 - 56</center>
| width="101" |
<center> 23 - 28</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage22 bf1c.jpg|60px|Link=Carnegie_stage_22]]</center>
| width="400" |
eyelids, external ears
|-
| width="40" |
<center>'''23'''</center>
| width="65" |
<center> 56 - 60</center>
| width="101" |
<center>27 - 31</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage23 bf1c.jpg|60px|Link=Carnegie_stage_23]]</center>
| width="400" |
rounded head, body and limbs
|-
| colspan="5" width="376" |
<center>Following this stage [[Fetal Development]] occurs until birth (approx 40 weeks)</center>
|}
 
 
 
== Carnegie Stage Table 2==
 
{| border="0"
| width="40" |
<center>'''Stage'''</center>
<center>'''Stage'''</center>
| width="58" |
| width="65" |
<center>'''Days''' (approx)</center>
<center>'''Days''' (approx)</center>
| width="44" |
| width="101" |
<center>'''Size''' (mm)</center>
<center>'''Size'''</center> <center>(mm)</center>
| width="122" |
| width="100" |
<center>'''Images<br />'''(not to scale, click image to see original)</center>
<center>'''Images<br />'''(not to scale)</center>
| width="122" |
| width="300" |
<center>'''Events'''</center>
<center>'''Events'''</center>
|-
|-
| width="30" |
| width="40" |
<center>'''1'''</center>
<center>'''1'''</center>
| width="58" |
| width="65" |
<center> 1 </center>('''week 1''')
<center> 1 </center>('''week 1''')
| width="44" |
| width="101" |
0.1-0.15
<center>0.1 - 0.15</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Human_zygote_two_pronuclei_02.jpg|60px|Link=Carnegie_stage_1]]</center>
<center>[[File:Human_zygote_two_pronuclei_02.jpg|60px|Link=Carnegie_stage_1]]</center>
| width="122" |
| width="300" |
fertilized oocyte, pronuclei
fertilized oocyte, pronuclei
|-
|-
| width="30" |
| width="40" |
<center>'''2'''</center>
<center>'''2'''</center>
| width="58" |
| width="65" |
<center> 2 - 3</center>
<center> 2 - 3</center>
| width="44" |
| width="101" |
0.1-0.2
<center>0.1 - 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_3.jpg|60px|Link=Carnegie_stage_2]]</center>
<center>[[File:Human_embryo_day_3.jpg|60px|Link=Carnegie_stage_2]]</center>
| width="122" |
| width="300" |
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
|-
|-
| width="30" |
| width="40" |
<center>'''3'''</center>
<center>'''3'''</center>
| width="58" |
| width="65" |
<center> 4 - 5</center>
<center> 4 - 5</center>
| width="44" |
| width="101" |
0.1-0.2
<center>0.1 - 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_5.jpg|60px|Link=Carnegie_stage_3]]</center>
<center>[[File:Human_embryo_day_5.jpg|60px|Link=Carnegie_stage_3]]</center>
| width="122" |
| width="300" |
loss of zona pellucida, free blastocyst
loss of zona pellucida, free blastocyst
|-
|-
| width="30" |
| width="40" |
<center>'''4'''</center>
<center>'''4'''</center>
| width="58" |
| width="65" |
<center> 5 - 6</center>
<center> 5 - 6</center>
| width="44" |
| width="101" |
0.1-0.2
<center>0.1 - 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="300" |
attaching blastocyst
attaching blastocyst
|-
|-
| width="30" |
| width="40" |
<center>'''5'''</center>
<center>'''5'''</center>
| width="58" |
| width="65" |
<center> 7 - 12<br /> ('''week 2''')</center>
<center> 7 - 12<br /> ('''week 2''')</center>
| width="44" |
| width="101" |
<center> 0.1-0.2</center>
<center> 0.1 - 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="300" |
implantation
implantation
|-
|-
| width="30" |
| width="40" |
<center>'''6'''</center>
<center>'''6'''</center>
| width="58" |
| width="65" |
<center> 13 - 15</center>
<center> 13 - 15</center>
| width="44" |
| width="101" |
<center> 0.2</center>
<center> 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="300" |
extraembryonic mesoderm, primitive streak
extraembryonic mesoderm, primitive streak
|-
|-
| width="30" |
| width="40" |
<center>'''7'''</center>
<center>'''7'''</center>
| width="58" |
| width="65" |
<center> 15 - 17 </center><center>('''week 3''')</center>
<center> 15 - 17 </center><center>('''week 3''')</center>
| width="44" |
| width="101" |
<center> 0.4</center>
<center> 0.4</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage7_features.jpg|60px|Link=Carnegie_stage_7]]</center>
<center>[[File:Stage7_features.jpg|60px|Link=Carnegie_stage_7]]</center>
| width="122" |
| width="300" |
gastrulation, notochordal process
gastrulation, notochordal process
|-
|-
| width="30" |
| width="40" |
<center>'''8'''</center>
<center>'''8'''</center>
| width="58" |
| width="65" |
<center> 17 - 19</center>
<center> 17 - 19</center>
| width="44" |
| width="101" |
<center> 1.0 - 1.5</center>
<center> 1.0 - 1.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage8_bf4.jpg|60px|Link=Carnegie_stage_8]]</center>
<center>[[File:Stage8_bf4.jpg|60px|Link=Carnegie_stage_8]]</center>
| width="122" |
| width="300" |
primitive pit, notochordal canal
primitive pit, notochordal canal
|-
|-
| width="30" |
| width="40" |
<center>'''9'''</center>
<center>'''9'''</center>
| width="58" |
| width="65" |
<center> 19 - 21</center>
<center> 19 - 21</center>
| width="44" |
| width="101" |
<center> 1.5 - 2.5</center>
<center> 1.5 - 2.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage9_dorsal.jpg|60px|Link=Carnegie_stage_9]]</center>
<center>[[File:Stage9_dorsal.jpg|60px|Link=Carnegie_stage_9]]</center>
| width="122" |
| width="300" |
'''Somite Number 1 - 3'''neural folds, cardiac primordium, head fold
'''Somite Number 1 - 3''' neural folds, cardiac primordium, head fold
|-
|-
| width="30" |
| width="40" |
<center>'''10'''</center>
<center>'''10'''</center>
| width="58" |
| width="65" |
<center> 22 - 23 </center>('''week 4''')
<center> 22 - 23 </center><center>('''week 4''')</center>
| width="44" |
| width="101" |
<center> 2 - 3.5</center>
<center> 2 - 3.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_10]]</center>
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_10]]</center>
| width="122" |
| width="300" |
'''Somite Number 4 - 12'''neural fold fuses
'''Somite Number 4 - 12''' neural fold fuses
|-
|-
| width="30" |
| width="40" |
<center>'''11'''</center>
<center>'''11'''</center>
| width="58" |
| width="65" |
<center> 23 - 26</center>
<center> 23 - 26</center>
| width="44" |
| width="101" |
<center> 2.5 - 4.5</center>
<center> 2.5 - 4.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_11]]</center>
<center>[[File:Stage11 bf7b.jpg|60px|Link=Carnegie_stage_11]]</center>
| width="122" |
| width="300" |
'''Somite Number 13 - 20'''rostral neuropore closes
'''Somite Number 13 - 20''' rostral neuropore closes
|-
|-
| width="30" |
| width="40" |
<center>'''12'''</center>
<center>'''12'''</center>
| width="58" |
| width="65" |
<center> 26 - 30</center>
<center> 26 - 30</center>
| width="44" |
| width="101" |
<center> 3 - 5</center>
<center> 3 - 5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_12]]</center>
<center>[[File:Stage12 bf5b.jpg|60px|Link=Carnegie_stage_12]]</center>
| width="122" |
| width="300" |
'''Somite Number 21 - 29'''caudal neuropore closes
'''Somite Number 21 - 29''' caudal neuropore closes
|-
|-
| width="30" |
| width="40" |
<center>'''13'''</center>
<center>'''13'''</center>
| width="58" |
| width="65" |
<center> 28 - 32 </center>('''week 5''')
<center> 28 - 32 </center>('''week 5''')
| width="44" |
| width="101" |
<center> 4 - 6</center>
<center> 4 - 6</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_13]]</center>
<center>[[File:Stage13 bf2c.jpg|60px|Link=Carnegie_stage_13]]</center>
| width="122" |
| width="300" |
'''Somite Number 30'''leg buds, lens placode, pharyngeal arches
'''Somite Number 30''' leg buds, lens placode, pharyngeal arches
|- bgcolor="#CCFFCC"
|- bgcolor="#CCFFCC"
| colspan="5" width="376" height="18" |
| colspan="5" width="376" height="18" |
<center> '''Stage 13/14''' shown in serial embryo sections series of Embryology Program</center>
<center> [[Carnegie_stage_13_-_serial_sections|Stage 13/14 shown in serial embryo sections]] series of Embryology Program</center>
|-
|-
| width="30" |
| width="40" |
<center>'''14'''</center>
<center>'''14'''</center>
| width="58" |
| width="65" |
<center> 31 - 35</center>
<center> 31 - 35</center>
| width="44" |
| width="101" |
<center> 5 - 7</center>
<center> 5 - 7</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_14]]</center>
<center>[[File:Stage14_bf2c.jpg|60px|Link=Carnegie_stage_14]]</center>
| width="122" |
| width="300" |
lens pit, optic cup
lens pit, optic cup
|-
|-
| width="30" |
| width="40" |
<center>'''15'''</center>
<center>'''15'''</center>
| width="58" |
| width="65" |
<center> 35 - 38</center>
<center> 35 - 38</center>
| width="44" |
| width="101" |
<center> 7 - 9</center>
<center> 7 - 9</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_15]]</center>
<center>[[File:Stage15 bf1c.jpg|60px|Link=Carnegie_stage_15]]</center>
| width="122" |
| width="300" |
lens vesicle, nasal pit, hand plate
lens vesicle, nasal pit, hand plate
|-
|-
| width="30" |
| width="40" |
<center>'''16'''</center>
<center>'''16'''</center>
| width="58" |
| width="65" |
<center> 37 - 42 </center>('''week 6''')
<center> 37 - 42 </center>('''week 6''')
| width="44" |
| width="101" |
<center> 8 - 11</center>
<center> 8 - 11</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage16.htm [[Image:CST16.gif]]]</center>
<center>[[File:Stage16 bf1c.jpg|60px|Link=Carnegie_stage_16]]</center>
| width="122" |
| width="300" |
nasal pits moved ventrally, auricular hillocks, foot plate
nasal pits moved ventrally, auricular hillocks, foot plate
|-
|-
| width="30" |
| width="40" |
<center>'''17'''</center>
<center>'''17'''</center>
| width="58" |
| width="65" |
<center> 42 - 44</center>
<center> 42 - 101</center>
| width="44" |
| width="101" |
<center> 11 - 14</center>
<center> 11 - 14</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_17]]</center>
<center>[[File:Stage17 bf1c.jpg|60px|Link=Carnegie_stage_17]]</center>
| width="122" |
| width="300" |
finger rays
finger rays
|-
|-
| width="30" |
| width="40" |
<center>'''18'''</center>
<center>'''18'''</center>
| width="58" |
| width="65" |
<center> 44 - 48 </center>('''week 7''')
<center> 101 - 48 </center>('''week 7''')
| width="44" |
| width="101" |
<center> 13 - 17</center>
<center> 13 - 17</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_18]]</center>
<center>[[File:Stage18 bf1c.jpg|60px|Link=Carnegie_stage_18]]</center>
| width="122" |
| width="300" |
ossification commences
ossification commences
|-
|-
| width="30" |
| width="40" |
<center>'''19'''</center>
<center>'''19'''</center>
| width="58" |
| width="65" |
<center> 48 - 51</center>
<center> 48 - 51</center>
| width="44" |
| width="101" |
<center> 16 - 18</center>
<center> 16 - 18</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_19]]</center>
<center>[[File:Stage19 bf1c.jpg|60px|Link=Carnegie_stage_19]]</center>
| width="122" |
| width="300" |
straightening of trunk
straightening of trunk
|-
|-
| width="30" |
| width="40" |
<center>'''20'''</center>
<center>'''20'''</center>
| width="58" |
| width="65" |
<center> 51 - 53 </center>('''week 8''')
<center> 51 - 53 </center>('''week 8''')
| width="44" |
| width="101" |
<center> 18 - 22</center>
<center> 18 - 22</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_20]]</center>
<center>[[File:Stage20 bf1c.jpg|60px|Link=Carnegie_stage_20]]</center>
| width="122" |
| width="300" |
upper limbs longer and bent at elbow
upper limbs longer and bent at elbow
|-
|-
| width="30" |
| width="40" |
<center>'''21'''</center>
<center>'''21'''</center>
| width="58" |
| width="65" |
<center>53 - 54</center>
<center>53 - 54</center>
| width="44" |
| width="101" |
<center>22 - 24</center>
<center>22 - 24</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_21]]</center>
<center>[[File:Stage21 bf1c.jpg|60px|Link=Carnegie_stage_21]]</center>
| width="122" |
| width="300" |
hands and feet turned inward
hands and feet turned inward
|- bgcolor="#FFCCCC"
|- bgcolor="#FFCCCC"
| colspan="5" width="376" |
| colspan="5" width="376" |
<center> '''Stage 22''' shown in serial embryo sections series of Embryology Program</center>
<center> [[Carnegie_stage_22_-_serial_sections|Stage 22 shown in serial embryo sections series]] of Embryology Program</center>
|-
|-
| width="30" |
| width="40" |
<center>'''22'''</center>
<center>'''22'''</center>
| width="58" |
| width="65" |
<center> 54 - 56</center>
<center> 54 - 56</center>
| width="44" |
| width="101" |
<center> 23 - 28</center>
<center> 23 - 28</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_22]]</center>
<center>[[File:Stage22 bf1c.jpg|60px|Link=Carnegie_stage_22]]</center>
| width="122" |
| width="300" |
eyelids, external ears
eyelids, external ears
|-
|-
| width="30" |
| width="40" |
<center>'''23'''</center>
<center>'''23'''</center>
| width="58" |
| width="65" |
<center> 56 - 60</center>
<center> 56 - 60</center>
| width="44" |
| width="101" |
<center>27 - 31</center>
<center>27 - 31</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_23]]</center>
<center>[[File:Stage23 bf1c.jpg|60px|Link=Carnegie_stage_23]]</center>
| width="122" |
| width="300" |
rounded head, body and limbs
rounded head, body and limbs
|-
|-
| colspan="5" width="376" |
| colspan="5" width="376" |
<center>Following this stage '''Fetal Development '''occurs until birth (approx 40 weeks)</center>
<center>Following this stage [[Fetal Development]] occurs until birth (approx 40 weeks)</center>
|}
|}


(Source: Rothenburger and Gay, 1995. and others)
== Carnegie Stage Table 3==
 
{| border="1"
| width="40" |
<center>'''Stage'''</center>
| width="65" |
<center>'''Days''' (approx)</center>
| width="101" |
<center>'''Size'''</center> <center>(mm)</center>
| width="100" |
<center>'''Images<br />'''(not to scale)</center>
| width="300" |
<center>'''Events'''</center>
|-
| width="40" |
<center>'''1'''</center>
| width="65" |
<center> 1 </center>('''week 1''')
| width="101" |
<center>0.1 - 0.15</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_zygote_two_pronuclei_02.jpg|60px|Link=Carnegie_stage_1]]</center>
| width="300" |
fertilized oocyte, pronuclei
|-
| width="40" |
<center>'''2'''</center>
| width="65" |
<center> 2 - 3</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_3.jpg|60px|Link=Carnegie_stage_2]]</center>
| width="300" |
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
|-
| width="40" |
<center>'''3'''</center>
| width="65" |
<center> 4 - 5</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
<center>[[File:Human_embryo_day_5.jpg|60px|Link=Carnegie_stage_3]]</center>
| width="300" |
loss of zona pellucida, free blastocyst
|-
| width="40" |
<center>'''4'''</center>
| width="65" |
<center> 5 - 6</center>
| width="101" |
<center>0.1 - 0.2</center>
| width="100" bgcolor="#000000" |
 
| width="300" |
attaching blastocyst
|-
| width="40" |
<center>'''5'''</center>
| width="65" |
<center> 7 - 12<br /> ('''week 2''')</center>
| width="101" |
<center> 0.1 - 0.2</center>
| width="100" bgcolor="#000000" |


== Carnegie Stage Table ==
| width="300" |
implantation
|-
| width="40" |
<center>'''6'''</center>
| width="65" |
<center> 13 - 15</center>
| width="101" |
<center> 0.2</center>
| width="100" bgcolor="#000000" |
 
| width="300" |
extraembryonic mesoderm, primitive streak
|-
| width="40" |
<center>'''7'''</center>
| width="65" |
<center> 15 - 17 </center><center>('''week 3''')</center>
| width="101" |
<center> 0.4</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage7_features.jpg|60px|Link=Carnegie_stage_7]]</center>
| width="300" |
gastrulation, notochordal process
|-
| width="40" |
<center>'''8'''</center>
| width="65" |
<center> 17 - 19</center>
| width="101" |
<center> 1.0 - 1.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage8_bf4.jpg|60px|Link=Carnegie_stage_8]]</center>
| width="300" |
primitive pit, notochordal canal
|-
| width="40" |
<center>'''9'''</center>
| width="65" |
<center> 19 - 21</center>
| width="101" |
<center> 1.5 - 2.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage9_dorsal.jpg|60px|Link=Carnegie_stage_9]]</center>
| width="300" |
'''Somite Number 1 - 3''' neural folds, cardiac primordium, head fold
|-
| width="40" |
<center>'''10'''</center>
| width="65" |
<center> 22 - 23 </center><center>('''week 4''')</center>
| width="101" |
<center> 2 - 3.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_10]]</center>
| width="300" |
'''Somite Number 4 - 12''' neural fold fuses
|-
| width="40" |
<center>'''11'''</center>
| width="65" |
<center> 23 - 26</center>
| width="101" |
<center> 2.5 - 4.5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage11 bf7b.jpg|60px|Link=Carnegie_stage_11]]</center>
| width="300" |
'''Somite Number 13 - 20''' rostral neuropore closes
|-
| width="40" |
<center>'''12'''</center>
| width="65" |
<center> 26 - 30</center>
| width="101" |
<center> 3 - 5</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage12 bf5b.jpg|60px|Link=Carnegie_stage_12]]</center>
| width="300" |
'''Somite Number 21 - 29''' caudal neuropore closes
|-
| width="40" |
<center>'''13'''</center>
| width="65" |
<center> 28 - 32 </center>('''week 5''')
| width="101" |
<center> 4 - 6</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage13 bf2c.jpg|60px|Link=Carnegie_stage_13]]</center>
| width="300" |
'''Somite Number 30''' leg buds, lens placode, pharyngeal arches
|- bgcolor="#CCFFCC"
| colspan="5" width="376" height="18" |
<center> [[Carnegie_stage_13_-_serial_sections|Stage 13/14 shown in serial embryo sections]] series of Embryology Program</center>
|-
| width="40" |
<center>'''14'''</center>
| width="65" |
<center> 31 - 35</center>
| width="101" |
<center> 5 - 7</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage14_bf2c.jpg|60px|Link=Carnegie_stage_14]]</center>
| width="300" |
lens pit, optic cup
|-
| width="40" |
<center>'''15'''</center>
| width="65" |
<center> 35 - 38</center>
| width="101" |
<center> 7 - 9</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage15 bf1c.jpg|60px|Link=Carnegie_stage_15]]</center>
| width="300" |
lens vesicle, nasal pit, hand plate
|-
| width="40" |
<center>'''16'''</center>
| width="65" |
<center> 37 - 42 </center>('''week 6''')
| width="101" |
<center> 8 - 11</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage16 bf1c.jpg|60px|Link=Carnegie_stage_16]]</center>
| width="300" |
nasal pits moved ventrally, auricular hillocks, foot plate
|-
| width="40" |
<center>'''17'''</center>
| width="65" |
<center> 42 - 101</center>
| width="101" |
<center> 11 - 14</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage17 bf1c.jpg|60px|Link=Carnegie_stage_17]]</center>
| width="300" |
finger rays
|-
| width="40" |
<center>'''18'''</center>
| width="65" |
<center> 101 - 48 </center>('''week 7''')
| width="101" |
<center> 13 - 17</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage18 bf1c.jpg|60px|Link=Carnegie_stage_18]]</center>
| width="300" |
ossification commences
|-
| width="40" |
<center>'''19'''</center>
| width="65" |
<center> 48 - 51</center>
| width="101" |
<center> 16 - 18</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage19 bf1c.jpg|60px|Link=Carnegie_stage_19]]</center>
| width="300" |
straightening of trunk
|-
| width="40" |
<center>'''20'''</center>
| width="65" |
<center> 51 - 53 </center>('''week 8''')
| width="101" |
<center> 18 - 22</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage20 bf1c.jpg|60px|Link=Carnegie_stage_20]]</center>
| width="300" |
upper limbs longer and bent at elbow
|-
| width="40" |
<center>'''21'''</center>
| width="65" |
<center>53 - 54</center>
| width="101" |
<center>22 - 24</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage21 bf1c.jpg|60px|Link=Carnegie_stage_21]]</center>
| width="300" |
hands and feet turned inward
|- bgcolor="#FFCCCC"
| colspan="5" width="376" |
<center> [[Carnegie_stage_22_-_serial_sections|Stage 22 shown in serial embryo sections series]] of Embryology Program</center>
|-
| width="40" |
<center>'''22'''</center>
| width="65" |
<center> 54 - 56</center>
| width="101" |
<center> 23 - 28</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage22 bf1c.jpg|60px|Link=Carnegie_stage_22]]</center>
| width="300" |
eyelids, external ears
|-
| width="40" |
<center>'''23'''</center>
| width="65" |
<center> 56 - 60</center>
| width="101" |
<center>27 - 31</center>
| width="100" bgcolor="#000000" |
<center>[[File:Stage23 bf1c.jpg|60px|Link=Carnegie_stage_23]]</center>
| width="300" |
rounded head, body and limbs
|-
| colspan="5" width="376" |
<center>Following this stage [[Fetal Development]] occurs until birth (approx 40 weeks)</center>
|}
 
== Carnegie Stage Table v2==


{| width="100%" border="1"
{| width="100%" border="1"
Line 288: Line 842:
| width="44" |
| width="44" |
<center>'''Size''' (mm)</center>
<center>'''Size''' (mm)</center>
| width="122" |
| width="100" |
<center>'''Images<br />'''(not to scale, click image to see original)</center>
<center>'''Images<br />'''(not to scale, click image to see original)</center>
| width="122" |
| width="100" |
<center>'''Events'''</center>
<center>'''Events'''</center>
|-
|-
Line 299: Line 853:
| width="44" |
| width="44" |
0.1-0.15
0.1-0.15
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[Image:CSt1.gif]]</center>
<center>[[File:Human_zygote_two_pronuclei_02.jpg|60px|Link=Carnegie_stage_1]]</center>
| width="122" |
| width="100" |
fertilized oocyte, pronuclei
fertilized oocyte, pronuclei
|-
|-
Line 310: Line 864:
| width="44" |
| width="44" |
0.1-0.2
0.1-0.2
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[../../Notes/week1.htm [[Image:CSt2.gif]]]</center>
<center>[[File:Human_embryo_day_3.jpg|60px|Link=Carnegie_stage_2]]</center>
| width="122" |
| width="100" |
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass
|-
|-
Line 321: Line 875:
| width="44" |
| width="44" |
0.1-0.2
0.1-0.2
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[[Image:CSt3.gif]]</center>
<center>[[File:Human_embryo_day_5.jpg|60px|Link=Carnegie_stage_3]]</center>
| width="122" |
| width="100" |
loss of zona pellucida, free blastocyst
loss of zona pellucida, free blastocyst
|-
|-
Line 332: Line 886:
| width="44" |
| width="44" |
0.1-0.2
0.1-0.2
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="100" |
attaching blastocyst
attaching blastocyst
|-
|-
Line 343: Line 897:
| width="44" |
| width="44" |
<center> 0.1-0.2</center>
<center> 0.1-0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="100" |
implantation
implantation
|-
|-
Line 354: Line 908:
| width="44" |
| width="44" |
<center> 0.2</center>
<center> 0.2</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |


| width="122" |
| width="100" |
extraembryonic mesoderm, primitive streak
extraembryonic mesoderm, primitive streak
|-
|-
Line 365: Line 919:
| width="44" |
| width="44" |
<center> 0.4</center>
<center> 0.4</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage7.htm [[Image:CST7A.gif]]]</center>
<center>[[File:Stage7_features.jpg|60px|Link=Carnegie_stage_7]]</center>
| width="122" |
| width="100" |
gastrulation, notochordal process
gastrulation, notochordal process
|-
|-
Line 376: Line 930:
| width="44" |
| width="44" |
<center> 1.0 - 1.5</center>
<center> 1.0 - 1.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage8.htm [[Image:CST8.gif]]]</center>
<center>[[File:Stage8_bf4.jpg|60px|Link=Carnegie_stage_8]]</center>
| width="122" |
| width="100" |
primitive pit, notochordal canal
primitive pit, notochordal canal
|-
|-
Line 387: Line 941:
| width="44" |
| width="44" |
<center> 1.5 - 2.5</center>
<center> 1.5 - 2.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage9.htm [[Image:CST9A.gif]]]</center>
<center>[[File:Stage9_dorsal.jpg|60px|Link=Carnegie_stage_9]]</center>
| width="122" |
| width="100" |
'''Somite Number 1 - 3'''neural folds, cardiac primordium, head fold
'''Somite Number 1 - 3'''neural folds, cardiac primordium, head fold
|-
|-
Line 398: Line 952:
| width="44" |
| width="44" |
<center> 2 - 3.5</center>
<center> 2 - 3.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage10.htm [[Image:CST10A.gif]]]</center>
<center>[[File:Stage10_bf4b.jpg|60px|Link=Carnegie_stage_10]]</center>
| width="122" |
| width="100" |
'''Somite Number 4 - 12'''neural fold fuses
'''Somite Number 4 - 12'''neural fold fuses
|-
|-
Line 409: Line 963:
| width="44" |
| width="44" |
<center> 2.5 - 4.5</center>
<center> 2.5 - 4.5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage11.htm [[Image:CST11.gif]]]</center>
<center>[[File:Stage11 bf7b.jpg|60px|Link=Carnegie_stage_11]]</center>
| width="122" |
| width="100" |
'''Somite Number 13 - 20'''rostral neuropore closes
'''Somite Number 13 - 20'''rostral neuropore closes
|-
|-
Line 420: Line 974:
| width="44" |
| width="44" |
<center> 3 - 5</center>
<center> 3 - 5</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage12.htm [[Image:CST12.gif]]]</center>
<center>[[File:Stage12 bf5b.jpg|60px|Link=Carnegie_stage_12]]</center>
| width="122" |
| width="100" |
'''Somite Number 21 - 29'''caudal neuropore closes
'''Somite Number 21 - 29'''caudal neuropore closes
|-
|-
Line 431: Line 985:
| width="44" |
| width="44" |
<center> 4 - 6</center>
<center> 4 - 6</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage13.htm [[Image:CST13.gif]]]</center>
<center>[[File:Stage13 bf2c.jpg|60px|Link=Carnegie_stage_13]]</center>
| width="122" |
| width="100" |
'''Somite Number 30'''leg buds, lens placode, pharyngeal arches
'''Somite Number 30'''leg buds, lens placode, pharyngeal arches
|- bgcolor="#CCFFCC"
|- bgcolor="#CCFFCC"
| colspan="5" width="376" height="18" |
| colspan="5" width="376" height="18" |
<center> '''Stage 13/14''' shown in serial embryo sections series of Embryology Program</center>
<center> [[Carnegie_stage_13_-_serial_sections|Stage 13/14 shown in serial embryo sections]] series of Embryology Program</center>
|-
|-
| width="30" |
| width="30" |
Line 445: Line 999:
| width="44" |
| width="44" |
<center> 5 - 7</center>
<center> 5 - 7</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage14.htm [[Image:CST14.gif]]]</center>
<center>[[File:Stage14_bf2c.jpg|60px|Link=Carnegie_stage_14]]</center>
| width="122" |
| width="100" |
lens pit, optic cup
lens pit, optic cup
|-
|-
Line 456: Line 1,010:
| width="44" |
| width="44" |
<center> 7 - 9</center>
<center> 7 - 9</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage15.htm [[Image:CST15.gif]]]</center>
<center>[[File:Stage15 bf1c.jpg|60px|Link=Carnegie_stage_15]]</center>
| width="122" |
| width="100" |
lens vesicle, nasal pit, hand plate
lens vesicle, nasal pit, hand plate
|-
|-
Line 467: Line 1,021:
| width="44" |
| width="44" |
<center> 8 - 11</center>
<center> 8 - 11</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage16.htm [[Image:CST16.gif]]]</center>
<center>[[File:Stage16 bf1c.jpg|60px|Link=Carnegie_stage_16]]</center>
| width="122" |
| width="100" |
nasal pits moved ventrally, auricular hillocks, foot plate
nasal pits moved ventrally, auricular hillocks, foot plate
|-
|-
Line 478: Line 1,032:
| width="44" |
| width="44" |
<center> 11 - 14</center>
<center> 11 - 14</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage17.htm [[Image:CST17.gif]]]</center>
<center>[[File:Stage17 bf1c.jpg|60px|Link=Carnegie_stage_17]]</center>
| width="122" |
| width="100" |
finger rays
finger rays
|-
|-
Line 489: Line 1,043:
| width="44" |
| width="44" |
<center> 13 - 17</center>
<center> 13 - 17</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage18.htm [[Image:CST18.gif]]]</center>
<center>[[File:Stage18 bf1c.jpg|60px|Link=Carnegie_stage_18]]</center>
| width="122" |
| width="100" |
ossification commences
ossification commences
|-
|-
Line 500: Line 1,054:
| width="44" |
| width="44" |
<center> 16 - 18</center>
<center> 16 - 18</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage19.htm [[Image:CST19.gif]]]</center>
<center>[[File:Stage19 bf1c.jpg|60px|Link=Carnegie_stage_19]]</center>
| width="122" |
| width="100" |
straightening of trunk
straightening of trunk
|-
|-
Line 511: Line 1,065:
| width="44" |
| width="44" |
<center> 18 - 22</center>
<center> 18 - 22</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage20.htm [[Image:CST20.gif]]]</center>
<center>[[File:Stage20 bf1c.jpg|60px|Link=Carnegie_stage_20]]</center>
| width="122" |
| width="100" |
upper limbs longer and bent at elbow
upper limbs longer and bent at elbow
|-
|-
Line 522: Line 1,076:
| width="44" |
| width="44" |
<center>22 - 24</center>
<center>22 - 24</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage21.htm [[Image:CST21.gif]]]</center>
<center>[[File:Stage21 bf1c.jpg|60px|Link=Carnegie_stage_21]]</center>
| width="122" |
| width="100" |
hands and feet turned inward
hands and feet turned inward
|- bgcolor="#FFCCCC"
|- bgcolor="#FFCCCC"
| colspan="5" width="376" |
| colspan="5" width="376" |
<center> '''Stage 22''' shown in serial embryo sections series of Embryology Program</center>
<center> [[Carnegie_stage_22_-_serial_sections|Stage 22 shown in serial embryo sections series]] of Embryology Program</center>
|-
|-
| width="30" |
| width="30" |
Line 536: Line 1,090:
| width="44" |
| width="44" |
<center> 23 - 28</center>
<center> 23 - 28</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage22.htm [[Image:CST22.gif]]]</center>
<center>[[File:Stage22 bf1c.jpg|60px|Link=Carnegie_stage_22]]</center>
| width="122" |
| width="100" |
eyelids, external ears
eyelids, external ears
|-
|-
Line 547: Line 1,101:
| width="44" |
| width="44" |
<center>27 - 31</center>
<center>27 - 31</center>
| width="122" bgcolor="#000000" |
| width="100" bgcolor="#000000" |
<center>[Stage23.htm [[Image:CST23.gif]]]</center>
<center>[[File:Stage23 bf1c.jpg|60px|Link=Carnegie_stage_23]]</center>
| width="122" |
| width="100" |
rounded head, body and limbs
rounded head, body and limbs
|-
|-
| colspan="5" width="376" |
| colspan="5" width="376" |
<center>Following this stage '''Fetal Development '''occurs until birth (approx 40 weeks)</center>
<center>Following this stage [[Fetal Development]] occurs until birth (approx 40 weeks)</center>
|}
|}


(Source: Rothenburger and Gay, 1995. and others)
==Embryo Stages==
 
===Developmental stages in human embryos: revised and new measurements===
 
Cells Tissues Organs. 2010;192(2):73-84. doi: 10.1159/000289817. Epub 2010 Feb 26.
 
 
O'Rahilly R, Müller F.
Source
School of Medicine, University of California, Davis, Calif., USA.
 
Abstract


==Embryo Stages==
The staging of human embryos, as distinct from seriation, depends on a morphological scheme devised by Streeter and completed by O'Rahilly, who proposed the term Carnegie stages. To avoid misconceptions and errors, and to place new findings in perspective, it is necessary to summarize the essentials of the Carnegie system: (1) Twenty-three stages cover the embryonic period, i. e. the first 8 postfertilizational weeks of development. (2) The system is based on internal as well as external features, and the use of only external criteria is subject to serious limitations. For example, precise delineation of stages 19-23 and of the embryonic-fetal transition depends on histological examination. (3) Prenatal measurements are not an integral component of the staging system, and hence a stage should never be assigned merely on the basis of embryonic length. A 20-mm embryo, for example, could belong to any of three stages. Measurements, however, are important for the assessment of age, and very few measurements are available for staged embryos. Presented here and based on accurate staging are the maximum diameter of the chorionic sac, the crown-heel length, the greatest length exclusive of the lower limbs, the biparietal diameter, the head circumference, the length of the hindbrain, the total length of the brain, and the lengths of the limbs as well as of their segments, including the foot length. (4) Prenatal ages are also not an integral part of the staging system and hence a stage should never be assigned merely on the basis of prenatal age. Ages, however, are of clinical importance and their estimate has been rendered more precise by accurate timing of fertilization followed by ultrasonography. Prenatal age is postfertilizational and hence some 2 weeks less than the postmenstrual interval. The term gestational age is ambiguous and should be discarded. Presented here is a new graph showing proposed estimates of age in relation to stages and based on current information.
Copyright 2010 S. Karger AG, Basel.
PMID 20185898




Line 572: Line 1,139:
Staged embryonic series are important as reference for different kinds of biological studies. I summarise problems that occur when using 'staging tables' of 'model organisms'. Investigations of developmental processes in a broad scope of taxa are becoming commonplace. Beginning in the 1990s, methods were developed to quantify and analyse developmental events in a phylogenetic framework. The algorithms associated with these methods are still under development, mainly due to difficulties of using non-independent characters. Nevertheless, the principle of comparing clearly defined newly occurring morphological features in development (events) in quantifying analyses was a key innovation for comparative embryonic research. Up to date no standard was set for how to define such events in a comparative approach. As a case study I compared the external development of 23 land vertebrate species with a focus on turtles, mainly based on reference staging tables. I excluded all the characters that are only identical for a particular species or general features that were only analysed in a few species. Based on these comparisons I defined 104 developmental characters that are common either for all vertebrates (61 characters), gnathostomes (26), tetrapods (3), amniotes (7), or only for sauropsids (7). Characters concern the neural tube, somite, ear, eye, limb, maxillary and mandibular process, pharyngeal arch, eyelid or carapace development. I present an illustrated guide listing all the defined events. This guide can be used for describing developmental series of any vertebrate species or for documenting specimen variability of a particular species. The guide incorporates drawings and photographs as well as consideration of species identifying developmental features such as colouration. The simple character-code of the guide is extendable to further characters pertaining to external and internal morphological, physiological, genetic or molecular development, and also for other vertebrate groups not examined here, such as Chondrichthyes or Actinopterygii. An online database to type in developmental events for different stages and species could be a basis for further studies in comparative embryology. By documenting developmental events with the standard code, sequence heterochrony studies (i.e. Parsimov) and studies on variability can use this broad comparative data set.
Staged embryonic series are important as reference for different kinds of biological studies. I summarise problems that occur when using 'staging tables' of 'model organisms'. Investigations of developmental processes in a broad scope of taxa are becoming commonplace. Beginning in the 1990s, methods were developed to quantify and analyse developmental events in a phylogenetic framework. The algorithms associated with these methods are still under development, mainly due to difficulties of using non-independent characters. Nevertheless, the principle of comparing clearly defined newly occurring morphological features in development (events) in quantifying analyses was a key innovation for comparative embryonic research. Up to date no standard was set for how to define such events in a comparative approach. As a case study I compared the external development of 23 land vertebrate species with a focus on turtles, mainly based on reference staging tables. I excluded all the characters that are only identical for a particular species or general features that were only analysed in a few species. Based on these comparisons I defined 104 developmental characters that are common either for all vertebrates (61 characters), gnathostomes (26), tetrapods (3), amniotes (7), or only for sauropsids (7). Characters concern the neural tube, somite, ear, eye, limb, maxillary and mandibular process, pharyngeal arch, eyelid or carapace development. I present an illustrated guide listing all the defined events. This guide can be used for describing developmental series of any vertebrate species or for documenting specimen variability of a particular species. The guide incorporates drawings and photographs as well as consideration of species identifying developmental features such as colouration. The simple character-code of the guide is extendable to further characters pertaining to external and internal morphological, physiological, genetic or molecular development, and also for other vertebrate groups not examined here, such as Chondrichthyes or Actinopterygii. An online database to type in developmental events for different stages and species could be a basis for further studies in comparative embryology. By documenting developmental events with the standard code, sequence heterochrony studies (i.e. Parsimov) and studies on variability can use this broad comparative data set.


PMID: 19521537
PMID 19521537  
http://www.ncbi.nlm.nih.gov/pubmed/19521537


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2693928
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2693928


http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005887
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005887


===A history of normal plates, tables and stages in vertebrate embryology===
===A history of normal plates, tables and stages in vertebrate embryology===
Line 590: Line 1,155:
Developmental biology is today unimaginable without the normal stages that define standard divisions of development. This history of normal stages, and the related normal plates and normal tables, shows how these standards have shaped and been shaped by disciplinary change in vertebrate embryology. The article highlights the Normal Plates of the Development of the Vertebrates edited by the German anatomist Franz Keibel (16 volumes, 1897-1938). These were a major response to problems in the relations between ontogeny and phylogeny that amounted in practical terms to a crisis in staging embryos, not just between, but (for some) also within species. Keibel's design adapted a plate by Wilhelm His and tables by Albert Oppel in order to go beyond the already controversial comparative plates of the Darwinist propagandist Ernst Haeckel. The project responded to local pressures, including intense concern with individual variation, but recruited internationally and mapped an embryological empire. Though theoretically inconclusive, the plates became standard laboratory tools and forged a network within which the Institut International d'Embryologie (today the International Society of Developmental Biologists) was founded in 1911. After World War I, experimentalists, led by Ross Harrison and Viktor Hamburger, and human embryologists, especially George Streeter at the Carnegie Department of Embryology, transformed Keibel's complex, bulky tomes to suit their own contrasting demands. In developmental biology after World War II, normal stages-reduced to a few journal pages-helped domesticate model organisms. Staging systems had emerged from discussions that questioned the very possibility of assigning an embryo to a stage. The historical issues resonate today as developmental biologists work to improve and extend stage series, to make results from different laboratories easier to compare and to take individual variation into account.
Developmental biology is today unimaginable without the normal stages that define standard divisions of development. This history of normal stages, and the related normal plates and normal tables, shows how these standards have shaped and been shaped by disciplinary change in vertebrate embryology. The article highlights the Normal Plates of the Development of the Vertebrates edited by the German anatomist Franz Keibel (16 volumes, 1897-1938). These were a major response to problems in the relations between ontogeny and phylogeny that amounted in practical terms to a crisis in staging embryos, not just between, but (for some) also within species. Keibel's design adapted a plate by Wilhelm His and tables by Albert Oppel in order to go beyond the already controversial comparative plates of the Darwinist propagandist Ernst Haeckel. The project responded to local pressures, including intense concern with individual variation, but recruited internationally and mapped an embryological empire. Though theoretically inconclusive, the plates became standard laboratory tools and forged a network within which the Institut International d'Embryologie (today the International Society of Developmental Biologists) was founded in 1911. After World War I, experimentalists, led by Ross Harrison and Viktor Hamburger, and human embryologists, especially George Streeter at the Carnegie Department of Embryology, transformed Keibel's complex, bulky tomes to suit their own contrasting demands. In developmental biology after World War II, normal stages-reduced to a few journal pages-helped domesticate model organisms. Staging systems had emerged from discussions that questioned the very possibility of assigning an embryo to a stage. The historical issues resonate today as developmental biologists work to improve and extend stage series, to make results from different laboratories easier to compare and to take individual variation into account.


PMID: 17183461  
PMID 17183461  


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1885287
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1885287


http://www.ijdb.ehu.es/web/paper.php?doi=10.1387/ijdb.062189nh
http://www.ijdb.ehu.es/web/paper.php?doi=10.1387/ijdb.062189nh
===Human post-implantation embryo collection: medical and surgical techniques===
Early Hum Dev. 1998 Jul 10;51(3):213-21.
Bullen PJ, Robson SC, Strachan T.
Source
Department of Fetal Medicine, University of Newcastle upon Tyne, Royal Victoria Infirmary, UK.
Abstract
Knowledge of the genetic control of early human development is limited with most information being extrapolated from studies in animal models. There is compelling evidence that undertaking gene expression studies in human embryos can be expected to dramatically enhance our understanding of embryonic formation and malformation. Such studies require the systematic and coordinated collection, storage and study of human embryos. We have successfully collected intact embryos from cases undergoing termination of pregnancy (TOP). Embryonic material was collected from 62% of attempts using a technique of surgical aspiration carried out under ultrasound guidance. Collection rates were lower after medical termination of pregnancy (41%) although the proportion of undisrupted embryos was identical with the two methods (26%). Surgical aspiration provided intact embryos between Carnegie stages (CS) 16-22 while earlier developmental stages were collected from medical terminations. Our collection of over 60 intact specimens, spanning Carnegie stages 10 to 22 (about 21 to 53 days of development) covers a huge window of critical developmental events and hence represents an exciting and valuable research resource.
PMID 9692791
===Morphological and molecular characteristics of living human fetuses between Carnegie stages 7 and 23: developmental stages in the post-implantation embryo===
Hum Reprod Update. 1997 Jan-Feb;3(1):3-23.
Harkness LM, Baird DT.
Source
Department of Obstetrics and Gynaecology, University of Edinburgh, UK.
Abstract
Determination of embryonic age groups or stages has been based on the Carnegie Institute collection started in 1887. Improved technology has enabled the building of a new collection of embryos of < 9 weeks gestation; these were then used to compare with the original Carnegie collection. The results suggest that in providing definitive stages that are rigidly bound by developmental events, limitations are placed on categorizing the embryo. Allocation of embryos to a specific stage can assist in identifying post-ovulatory age but overlaps between stages could lead to classification into an incorrect stage.
PMID 9193935
===The rate of growth in young human embryos of Streeter's horizons. 13 to 23===
Iffy L, Shepard TH, Jakobovits A, Lemire RJ, Kerner P.
Acta Anat (Basel). 1967;66(2):178-86.
PMID 6050342
===Report Upon the Collection of Human Embryos at the John Hopkins University===
Mall, F.P.
The Anatomical Record Volume 5, Issue 7, pages 343–357, July 1911

Latest revision as of 00:27, 22 November 2013

Carnegie Stage Table 1

Stage
Days (approx)
Size
(mm)
Images
(not to scale)
Events
1
1
(week 1)
0.1 - 0.15
Link=Carnegie_stage_1

fertilized oocyte, pronuclei

2
2 - 3
0.1 - 0.2
Link=Carnegie_stage_2

cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass

3
4 - 5
0.1 - 0.2
Link=Carnegie_stage_3

loss of zona pellucida, free blastocyst

4
5 - 6
0.1 - 0.2

attaching blastocyst

5
7 - 12
(week 2)
0.1 - 0.2

implantation

6
13 - 15
0.2

extraembryonic mesoderm, primitive streak

7
15 - 17
(week 3)
0.4
Link=Carnegie_stage_7

gastrulation, notochordal process

8
17 - 19
1.0 - 1.5
Link=Carnegie_stage_8

primitive pit, notochordal canal

9
19 - 21
1.5 - 2.5
Link=Carnegie_stage_9

Somite Number 1 - 3 neural folds, cardiac primordium, head fold

10
22 - 23
(week 4)
2 - 3.5
Link=Carnegie_stage_10

Somite Number 4 - 12 neural fold fuses

11
23 - 26
2.5 - 4.5
Link=Carnegie_stage_11

Somite Number 13 - 20 rostral neuropore closes

12
26 - 30
3 - 5
Link=Carnegie_stage_12

Somite Number 21 - 29 caudal neuropore closes

13
28 - 32
(week 5)
4 - 6
Link=Carnegie_stage_13

Somite Number 30 leg buds, lens placode, pharyngeal arches

Stage 13/14 shown in serial embryo sections series of Embryology Program
14
31 - 35
5 - 7
Link=Carnegie_stage_14

lens pit, optic cup

15
35 - 38
7 - 9
Link=Carnegie_stage_15

lens vesicle, nasal pit, hand plate

16
37 - 42
(week 6)
8 - 11
Link=Carnegie_stage_16

nasal pits moved ventrally, auricular hillocks, foot plate

17
42 - 101
11 - 14
Link=Carnegie_stage_17

finger rays

18
101 - 48
(week 7)
13 - 17
Link=Carnegie_stage_18

ossification commences

19
48 - 51
16 - 18
Link=Carnegie_stage_19

straightening of trunk

20
51 - 53
(week 8)
18 - 22
Link=Carnegie_stage_20

upper limbs longer and bent at elbow

21
53 - 54
22 - 24
Link=Carnegie_stage_21

hands and feet turned inward

Stage 22 shown in serial embryo sections series of Embryology Program
22
54 - 56
23 - 28
Link=Carnegie_stage_22

eyelids, external ears

23
56 - 60
27 - 31
Link=Carnegie_stage_23

rounded head, body and limbs

Following this stage Fetal Development occurs until birth (approx 40 weeks)


Carnegie Stage Table 2

Stage
Days (approx)
Size
(mm)
Images
(not to scale)
Events
1
1
(week 1)
0.1 - 0.15
Link=Carnegie_stage_1

fertilized oocyte, pronuclei

2
2 - 3
0.1 - 0.2
Link=Carnegie_stage_2

cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass

3
4 - 5
0.1 - 0.2
Link=Carnegie_stage_3

loss of zona pellucida, free blastocyst

4
5 - 6
0.1 - 0.2

attaching blastocyst

5
7 - 12
(week 2)
0.1 - 0.2

implantation

6
13 - 15
0.2

extraembryonic mesoderm, primitive streak

7
15 - 17
(week 3)
0.4
Link=Carnegie_stage_7

gastrulation, notochordal process

8
17 - 19
1.0 - 1.5
Link=Carnegie_stage_8

primitive pit, notochordal canal

9
19 - 21
1.5 - 2.5
Link=Carnegie_stage_9

Somite Number 1 - 3 neural folds, cardiac primordium, head fold

10
22 - 23
(week 4)
2 - 3.5
Link=Carnegie_stage_10

Somite Number 4 - 12 neural fold fuses

11
23 - 26
2.5 - 4.5
Link=Carnegie_stage_11

Somite Number 13 - 20 rostral neuropore closes

12
26 - 30
3 - 5
Link=Carnegie_stage_12

Somite Number 21 - 29 caudal neuropore closes

13
28 - 32
(week 5)
4 - 6
Link=Carnegie_stage_13

Somite Number 30 leg buds, lens placode, pharyngeal arches

Stage 13/14 shown in serial embryo sections series of Embryology Program
14
31 - 35
5 - 7
Link=Carnegie_stage_14

lens pit, optic cup

15
35 - 38
7 - 9
Link=Carnegie_stage_15

lens vesicle, nasal pit, hand plate

16
37 - 42
(week 6)
8 - 11
Link=Carnegie_stage_16

nasal pits moved ventrally, auricular hillocks, foot plate

17
42 - 101
11 - 14
Link=Carnegie_stage_17

finger rays

18
101 - 48
(week 7)
13 - 17
Link=Carnegie_stage_18

ossification commences

19
48 - 51
16 - 18
Link=Carnegie_stage_19

straightening of trunk

20
51 - 53
(week 8)
18 - 22
Link=Carnegie_stage_20

upper limbs longer and bent at elbow

21
53 - 54
22 - 24
Link=Carnegie_stage_21

hands and feet turned inward

Stage 22 shown in serial embryo sections series of Embryology Program
22
54 - 56
23 - 28
Link=Carnegie_stage_22

eyelids, external ears

23
56 - 60
27 - 31
Link=Carnegie_stage_23

rounded head, body and limbs

Following this stage Fetal Development occurs until birth (approx 40 weeks)

Carnegie Stage Table 3

Stage
Days (approx)
Size
(mm)
Images
(not to scale)
Events
1
1
(week 1)
0.1 - 0.15
Link=Carnegie_stage_1

fertilized oocyte, pronuclei

2
2 - 3
0.1 - 0.2
Link=Carnegie_stage_2

cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass

3
4 - 5
0.1 - 0.2
Link=Carnegie_stage_3

loss of zona pellucida, free blastocyst

4
5 - 6
0.1 - 0.2

attaching blastocyst

5
7 - 12
(week 2)
0.1 - 0.2

implantation

6
13 - 15
0.2

extraembryonic mesoderm, primitive streak

7
15 - 17
(week 3)
0.4
Link=Carnegie_stage_7

gastrulation, notochordal process

8
17 - 19
1.0 - 1.5
Link=Carnegie_stage_8

primitive pit, notochordal canal

9
19 - 21
1.5 - 2.5
Link=Carnegie_stage_9

Somite Number 1 - 3 neural folds, cardiac primordium, head fold

10
22 - 23
(week 4)
2 - 3.5
Link=Carnegie_stage_10

Somite Number 4 - 12 neural fold fuses

11
23 - 26
2.5 - 4.5
Link=Carnegie_stage_11

Somite Number 13 - 20 rostral neuropore closes

12
26 - 30
3 - 5
Link=Carnegie_stage_12

Somite Number 21 - 29 caudal neuropore closes

13
28 - 32
(week 5)
4 - 6
Link=Carnegie_stage_13

Somite Number 30 leg buds, lens placode, pharyngeal arches

Stage 13/14 shown in serial embryo sections series of Embryology Program
14
31 - 35
5 - 7
Link=Carnegie_stage_14

lens pit, optic cup

15
35 - 38
7 - 9
Link=Carnegie_stage_15

lens vesicle, nasal pit, hand plate

16
37 - 42
(week 6)
8 - 11
Link=Carnegie_stage_16

nasal pits moved ventrally, auricular hillocks, foot plate

17
42 - 101
11 - 14
Link=Carnegie_stage_17

finger rays

18
101 - 48
(week 7)
13 - 17
Link=Carnegie_stage_18

ossification commences

19
48 - 51
16 - 18
Link=Carnegie_stage_19

straightening of trunk

20
51 - 53
(week 8)
18 - 22
Link=Carnegie_stage_20

upper limbs longer and bent at elbow

21
53 - 54
22 - 24
Link=Carnegie_stage_21

hands and feet turned inward

Stage 22 shown in serial embryo sections series of Embryology Program
22
54 - 56
23 - 28
Link=Carnegie_stage_22

eyelids, external ears

23
56 - 60
27 - 31
Link=Carnegie_stage_23

rounded head, body and limbs

Following this stage Fetal Development occurs until birth (approx 40 weeks)

Carnegie Stage Table v2

Stage
Days (approx)
Size (mm)
Images
(not to scale, click image to see original)
Events
1
1
(week 1)

0.1-0.15

Link=Carnegie_stage_1

fertilized oocyte, pronuclei

2
2 - 3

0.1-0.2

Link=Carnegie_stage_2

cell division with reduction in cytoplasmic volume, formation of inner and outer cell mass

3
4 - 5

0.1-0.2

Link=Carnegie_stage_3

loss of zona pellucida, free blastocyst

4
5 - 6

0.1-0.2

attaching blastocyst

5
7 - 12
(week 2)
0.1-0.2

implantation

6
13 - 15
0.2

extraembryonic mesoderm, primitive streak

7
15 - 17
(week 3)
0.4
Link=Carnegie_stage_7

gastrulation, notochordal process

8
17 - 19
1.0 - 1.5
Link=Carnegie_stage_8

primitive pit, notochordal canal

9
19 - 21
1.5 - 2.5
Link=Carnegie_stage_9

Somite Number 1 - 3neural folds, cardiac primordium, head fold

10
22 - 23
(week 4)
2 - 3.5
Link=Carnegie_stage_10

Somite Number 4 - 12neural fold fuses

11
23 - 26
2.5 - 4.5
Link=Carnegie_stage_11

Somite Number 13 - 20rostral neuropore closes

12
26 - 30
3 - 5
Link=Carnegie_stage_12

Somite Number 21 - 29caudal neuropore closes

13
28 - 32
(week 5)
4 - 6
Link=Carnegie_stage_13

Somite Number 30leg buds, lens placode, pharyngeal arches

Stage 13/14 shown in serial embryo sections series of Embryology Program
14
31 - 35
5 - 7
Link=Carnegie_stage_14

lens pit, optic cup

15
35 - 38
7 - 9
Link=Carnegie_stage_15

lens vesicle, nasal pit, hand plate

16
37 - 42
(week 6)
8 - 11
Link=Carnegie_stage_16

nasal pits moved ventrally, auricular hillocks, foot plate

17
42 - 44
11 - 14
Link=Carnegie_stage_17

finger rays

18
44 - 48
(week 7)
13 - 17
Link=Carnegie_stage_18

ossification commences

19
48 - 51
16 - 18
Link=Carnegie_stage_19

straightening of trunk

20
51 - 53
(week 8)
18 - 22
Link=Carnegie_stage_20

upper limbs longer and bent at elbow

21
53 - 54
22 - 24
Link=Carnegie_stage_21

hands and feet turned inward

Stage 22 shown in serial embryo sections series of Embryology Program
22
54 - 56
23 - 28
Link=Carnegie_stage_22

eyelids, external ears

23
56 - 60
27 - 31
Link=Carnegie_stage_23

rounded head, body and limbs

Following this stage Fetal Development occurs until birth (approx 40 weeks)

Embryo Stages

Developmental stages in human embryos: revised and new measurements

Cells Tissues Organs. 2010;192(2):73-84. doi: 10.1159/000289817. Epub 2010 Feb 26.


O'Rahilly R, Müller F. Source School of Medicine, University of California, Davis, Calif., USA.

Abstract

The staging of human embryos, as distinct from seriation, depends on a morphological scheme devised by Streeter and completed by O'Rahilly, who proposed the term Carnegie stages. To avoid misconceptions and errors, and to place new findings in perspective, it is necessary to summarize the essentials of the Carnegie system: (1) Twenty-three stages cover the embryonic period, i. e. the first 8 postfertilizational weeks of development. (2) The system is based on internal as well as external features, and the use of only external criteria is subject to serious limitations. For example, precise delineation of stages 19-23 and of the embryonic-fetal transition depends on histological examination. (3) Prenatal measurements are not an integral component of the staging system, and hence a stage should never be assigned merely on the basis of embryonic length. A 20-mm embryo, for example, could belong to any of three stages. Measurements, however, are important for the assessment of age, and very few measurements are available for staged embryos. Presented here and based on accurate staging are the maximum diameter of the chorionic sac, the crown-heel length, the greatest length exclusive of the lower limbs, the biparietal diameter, the head circumference, the length of the hindbrain, the total length of the brain, and the lengths of the limbs as well as of their segments, including the foot length. (4) Prenatal ages are also not an integral part of the staging system and hence a stage should never be assigned merely on the basis of prenatal age. Ages, however, are of clinical importance and their estimate has been rendered more precise by accurate timing of fertilization followed by ultrasonography. Prenatal age is postfertilizational and hence some 2 weeks less than the postmenstrual interval. The term gestational age is ambiguous and should be discarded. Presented here is a new graph showing proposed estimates of age in relation to stages and based on current information. Copyright 2010 S. Karger AG, Basel. PMID 20185898


A standard system to study vertebrate embryos

PLoS One. 2009 Jun 12;4(6):e5887.

Werneburg I.

Paläontologisches Museum und Institut der Universität Zürich, Zürich, Switzerland. ingmar_werneburg@yahoo.de

Abstract

Staged embryonic series are important as reference for different kinds of biological studies. I summarise problems that occur when using 'staging tables' of 'model organisms'. Investigations of developmental processes in a broad scope of taxa are becoming commonplace. Beginning in the 1990s, methods were developed to quantify and analyse developmental events in a phylogenetic framework. The algorithms associated with these methods are still under development, mainly due to difficulties of using non-independent characters. Nevertheless, the principle of comparing clearly defined newly occurring morphological features in development (events) in quantifying analyses was a key innovation for comparative embryonic research. Up to date no standard was set for how to define such events in a comparative approach. As a case study I compared the external development of 23 land vertebrate species with a focus on turtles, mainly based on reference staging tables. I excluded all the characters that are only identical for a particular species or general features that were only analysed in a few species. Based on these comparisons I defined 104 developmental characters that are common either for all vertebrates (61 characters), gnathostomes (26), tetrapods (3), amniotes (7), or only for sauropsids (7). Characters concern the neural tube, somite, ear, eye, limb, maxillary and mandibular process, pharyngeal arch, eyelid or carapace development. I present an illustrated guide listing all the defined events. This guide can be used for describing developmental series of any vertebrate species or for documenting specimen variability of a particular species. The guide incorporates drawings and photographs as well as consideration of species identifying developmental features such as colouration. The simple character-code of the guide is extendable to further characters pertaining to external and internal morphological, physiological, genetic or molecular development, and also for other vertebrate groups not examined here, such as Chondrichthyes or Actinopterygii. An online database to type in developmental events for different stages and species could be a basis for further studies in comparative embryology. By documenting developmental events with the standard code, sequence heterochrony studies (i.e. Parsimov) and studies on variability can use this broad comparative data set.

PMID 19521537

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2693928

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005887

A history of normal plates, tables and stages in vertebrate embryology

Int J Dev Biol. 2007;51(1):1-26.

Hopwood N.

Department of History and Philosophy of Science, University of Cambridge, UK. ndh12@cam.ac.uk Abstract Developmental biology is today unimaginable without the normal stages that define standard divisions of development. This history of normal stages, and the related normal plates and normal tables, shows how these standards have shaped and been shaped by disciplinary change in vertebrate embryology. The article highlights the Normal Plates of the Development of the Vertebrates edited by the German anatomist Franz Keibel (16 volumes, 1897-1938). These were a major response to problems in the relations between ontogeny and phylogeny that amounted in practical terms to a crisis in staging embryos, not just between, but (for some) also within species. Keibel's design adapted a plate by Wilhelm His and tables by Albert Oppel in order to go beyond the already controversial comparative plates of the Darwinist propagandist Ernst Haeckel. The project responded to local pressures, including intense concern with individual variation, but recruited internationally and mapped an embryological empire. Though theoretically inconclusive, the plates became standard laboratory tools and forged a network within which the Institut International d'Embryologie (today the International Society of Developmental Biologists) was founded in 1911. After World War I, experimentalists, led by Ross Harrison and Viktor Hamburger, and human embryologists, especially George Streeter at the Carnegie Department of Embryology, transformed Keibel's complex, bulky tomes to suit their own contrasting demands. In developmental biology after World War II, normal stages-reduced to a few journal pages-helped domesticate model organisms. Staging systems had emerged from discussions that questioned the very possibility of assigning an embryo to a stage. The historical issues resonate today as developmental biologists work to improve and extend stage series, to make results from different laboratories easier to compare and to take individual variation into account.

PMID 17183461

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1885287

http://www.ijdb.ehu.es/web/paper.php?doi=10.1387/ijdb.062189nh


Human post-implantation embryo collection: medical and surgical techniques

Early Hum Dev. 1998 Jul 10;51(3):213-21.

Bullen PJ, Robson SC, Strachan T. Source Department of Fetal Medicine, University of Newcastle upon Tyne, Royal Victoria Infirmary, UK.

Abstract

Knowledge of the genetic control of early human development is limited with most information being extrapolated from studies in animal models. There is compelling evidence that undertaking gene expression studies in human embryos can be expected to dramatically enhance our understanding of embryonic formation and malformation. Such studies require the systematic and coordinated collection, storage and study of human embryos. We have successfully collected intact embryos from cases undergoing termination of pregnancy (TOP). Embryonic material was collected from 62% of attempts using a technique of surgical aspiration carried out under ultrasound guidance. Collection rates were lower after medical termination of pregnancy (41%) although the proportion of undisrupted embryos was identical with the two methods (26%). Surgical aspiration provided intact embryos between Carnegie stages (CS) 16-22 while earlier developmental stages were collected from medical terminations. Our collection of over 60 intact specimens, spanning Carnegie stages 10 to 22 (about 21 to 53 days of development) covers a huge window of critical developmental events and hence represents an exciting and valuable research resource. PMID 9692791


Morphological and molecular characteristics of living human fetuses between Carnegie stages 7 and 23: developmental stages in the post-implantation embryo

Hum Reprod Update. 1997 Jan-Feb;3(1):3-23.

Harkness LM, Baird DT. Source Department of Obstetrics and Gynaecology, University of Edinburgh, UK.

Abstract

Determination of embryonic age groups or stages has been based on the Carnegie Institute collection started in 1887. Improved technology has enabled the building of a new collection of embryos of < 9 weeks gestation; these were then used to compare with the original Carnegie collection. The results suggest that in providing definitive stages that are rigidly bound by developmental events, limitations are placed on categorizing the embryo. Allocation of embryos to a specific stage can assist in identifying post-ovulatory age but overlaps between stages could lead to classification into an incorrect stage.

PMID 9193935

The rate of growth in young human embryos of Streeter's horizons. 13 to 23

Iffy L, Shepard TH, Jakobovits A, Lemire RJ, Kerner P.

Acta Anat (Basel). 1967;66(2):178-86.

PMID 6050342

Report Upon the Collection of Human Embryos at the John Hopkins University

Mall, F.P.

The Anatomical Record Volume 5, Issue 7, pages 343–357, July 1911