Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
3 weeks gestation
|
The epidermis is 1 cell thick.
|
|
|
|
6 weeks
|
The volar pads appear as localized bulges on the palm and fingers, starting on the palm and interdigital areas, followed by the fingers. The hand is paddle shaped.
|
|
|
|
8 weeks
|
The digits have separated and the thumb has rotated. The volar pads are more pronounced and some flexion creases have appeared.
|
|
|
|
10.5-12 weeks
|
Volar pads begin to regress at random times between each pad. The pads are asymetrical. Primary ridges begin to form on the underside of the epidermis, continuing until the surface is covered.
|
|
|
|
15-17 weeks
|
Secondary ridges begin to appear between the existing primary ridges, while primary ridge development stops in that area. This is called the "Time of Differentiation".
|
Incipient ridges form, mirroring the furrows on the surface.
|
|
|
20 weeks
|
The secondary ridges are established and the final friction ridge configuration is complete.
|
|
|
|
20-24 weeks
|
The secondary ridges continue to develop, and papillary pegs are formed. Once the secondary ridges are formed, the friction ridge will be visible. At 24 weeks, the system has matured.
|
|
