|
Bones
|
Timing
|
Source |
The jaws, ribs, and vertebrae are
changing from cartilage to bone.
|
7th week after conception |
Rugh, p 52 |
| Ossification of the bones of the upper
limbs has begun. |
End of the 7th week after fertilization |
Moore, p 96 |
| Ossification begins in the lower limbs,
and is first recognizable in the femur. |
8th week after fertilization |
Moore, p 97 |
| The skeleton is developing. |
2nd month after conception |
Rugh, p 52 |
| Primary ossification centers appear
in the, skelton, especially in the skull and long
bones. |
End of the 12th week after fertilization |
Moore, p 110, Sadler, p 113 |
| Bones are clearly visible in ulatrsound
images. |
Beginning of the 16th week after fertilization |
Moore, p 112 |
| |
|
|
