The thoracic length is the distance from cephalic end of the sternum to the diaphragm in the fetal midline.
Fetal thoracic length
|
weeks |
50th percentile |
5th percentile |
95th percentile |
|
16 |
2 cm |
1.1 cm |
3 cm |
|
17 |
2.2 cm |
1.3 cm |
3.2 cm |
|
18 |
2.4 cm |
1.4 cm |
3.4 cm |
|
19 |
2.7 cm |
1.6 cm |
3.6 cm |
|
20 |
2.8 cm |
1.8 cm |
3.8 cm |
|
21 |
3 cm |
2 cm |
4 cm |
|
22 |
3.2 cm |
2.2 cm |
4.1 cm |
|
23 |
3.4 cm |
2.4 cm |
4.3 cm |
|
24 |
3.5 cm |
2.6 cm |
4.5 cm |
|
25 |
3.7 cm |
2.8 cm |
4.7 cm |
|
26 |
3.9 cm |
2.9 cm |
4.9 cm |
|
27 |
4.1 cm |
3.1 cm |
5.1 cm |
|
28 |
4.3 cm |
3.3 cm |
5.4 cm |
|
29 |
4.5 cm |
3.5 cm |
5.5 cm |
|
30 |
4.7 cm |
3.7 cm |
5.6 cm |
|
31 |
4.9 cm |
3.9 cm |
5.8 cm |
|
32 |
5 cm |
4.1 cm |
6 cm |
|
33 |
5.2 cm |
4.3 cm |
6.2 cm |
|
34 |
5.4 cm |
4.4 cm |
6.4 cm |
|
35 |
5.6 cm |
4.6 cm |
6.6 cm |
|
36 |
5.8 cm |
4.8 cm |
6.8 cm |
|
37 |
6 cm |
5 cm |
7 cm |
|
38 |
6.2 cm |
5.2 cm |
7.1 cm |
|
39 |
6.4 cm |
5.4 cm |
7.3 cm |
|
40 |
6.5 cm |
5.6 cm |
7.5 cm |
from Chitkara (1987)
When this data is analyzed in JMP, the following equations are obtained:
50th percentile for thoracic length in cm =
= (0.1876154 * (weeks of gestation)) - 0.957231
5th percentile for thoracic length in cm =
= (0.1876154 * (weeks of gestation)) - 1.933231
95th percentile for thoracic length in cm =
= (0.1871538 * (weeks of gestation)) - 0.0316923
week of gestation =
= (5.326537 * (50th percentile thoracic length in cm)) + 5.1171969
= (5.327654* (5th percentile thoracic length in cm)) + 10.312189
= (5.338992 * (95th percentile thoracic length in cm)) - 0.147166
Specialty: Obstetrics & Gynecology, Pedatrics
ICD-10: ,
