| 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
|
Earlier mandibular and hyoid arteries
|
| 1075
|
6
|
3, 4
|
Subclavian
|
| 588
|
4
|
3, 4
|
Earlier mandibular and hyoid arteries
|
| 873
|
6
|
3, 4
|
Ventral tract on cord
|
| 988
|
6
|
3, 4
|
| 1380
|
4
|
3, 4; pulmonary arches almost complete
|
| 2841
|
4
|
3, 4; one so-called fifth arch; pulmonary almost complete
|
Early formation of basilar artery
|
| Just before completion of pulmonary arch; estimated average length 6 mm; 36th day of development
|
| 810
|
5
|
3, 4, and pulmonary arches
|
Late stage in formation of basilar artery; Splitting of aortic sac distinct. Unpaired aorta complete
|
| 1354
|
6
|
3, 4, and pulmonary arches
|
|
| 617
|
7
|
3, 4, two so-called fifth arches, and pulmonary arches
|
Subclavian artery surrounded by brachial plexus. Splitting of sac well marked
|
| 792
|
8
|
3, 4, and pulmonary arches
|
Pulmonary and 4th arches widely separated below
|
| 1121
|
11
|
3, 4, and pulmonary arches
|
Right pulmonary artery small; basilar rounded; 4th and pulmonary still further apart
|
| 721
|
9
|
3, 4, and pulmonary arches
|
Cervical segmental arteries becoming interrupted
|
| 163
|
9
|
3, 4, and pulmonary arches
|
Anastomoses of cervical segmental arteries to form the vertebral artery are nearly complete
|
| 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.
|
