Embryo No.
|
Length in mm
|
Arches present
|
Characteristic features
|
1878
|
1.3
|
1
|
slightly plexiform. Presomite stage
|
1201
|
2
|
1
|
|
391
|
2
|
1
|
7 somites
|
470
|
4
|
1
|
neuropore open; 14 to 16 somites
|
2053
|
3
|
1, 2 beginning
|
Anterior neuropore closed; 20 somites; transverse anastomoses between primitive aortae
|
1201b
|
3
|
1, 2
|
836
|
4
|
2, 3
|
Earlier mandibular artery ; paired longitudinal neural arteries; no ventral tract on cord
|
Just before establishment of fourth arch; estimated average length 4 mm; 31st day of development
|
826
|
5
|
3, 4
|
1075
|
6
|
3, 4
|
588
|
4
|
3, 4
|
873
|
6
|
3, 4
|
988
|
6
|
3, 4
|
1380
|
4
|
3, 4; pulmonary arches almost complete
|
2841
|
4
|
3, 4; one so-called fifth arch; pulmonary almost complete
|
Just before completion of pulmonary arch; estimated average length 6 mm; 36th day of development
|
810
|
5
|
3, 4, and pulmonary arches
|
1354
|
6
|
3, 4, and pulmonary arches
|
617
|
7
|
3, 4, two so-called fifth arches, and pulmonary arches
|
792
|
8
|
3, 4, and pulmonary arches
|
1121
|
11
|
3, 4, and pulmonary arches
|
721
|
9
|
3, 4, and pulmonary arches
|
163
|
9
|
3, 4, and pulmonary arches
|
Time of interruption of pulmonary arch and branchial period; estimated average length 12 mm; 45th day of development
|
1771
|
13
|
3, 4, left pulmonary and remnant of right pulmonary arch
|
544
|
10
|
|
940
|
14
|
|
1909
|
15
|
|
492
|
16
|
|
74
|
16
|
End of period of rapid descent of heart and arteries; estimated average length 18 mm; 50th day of development
|
1390
|
|
460
|
|
2937
|
|
886
|
|
Estimates based on Keibel F. and Mall FP. Manual of Human Embryology II. (1912) J. B. Lippincott Company, Philadelphia. curve of length and age.
|
Reference: Congdon ED. Transformation of the aortic-arch system during the development of the human embryo. (1922) Contrib. Embryol., Carnegie Inst. Wash. Publ 277, 14:47-110.
|