Template:Insert timeline
<gallery caption="Development of the Mouse Embryo" widths="100px" heights="100px" perrow="5" File:Day 0 one cell stage.jpg|100px|Embryo at Day 0 File:Day 1 dividing egg.JPG|100px|Day 1 File:Day 2 morula.JPG|100px|Day 2 File:Day 3 Advanced Segmentation.JPG|100px|Day 3 File:Day 4 Blastocyst.JPG|100px|Day 4 File:Day 4.5 Implantation.JPG|100px|Day 4.5 File:Day 5 Formation of Egg Cylinder.JPG|100px|Day 5 File:Day 6 Differentiation of Egg Cylinder.JPG|100px|Day 6 File:Day 6.5 Advanced Endometrial Reaction.JPG|100px|Day 6.5 File:Day 7 Amnion.JPG|100px|Day 7 File:Day 7.5 Neural plate, presomite stage.JPG|100px|Day 7.5 File:Day 8 First Somites.JPG|100px|Day 8 File:Day 8.5 Turning of embryo.JPG|100px|Day 8.5 File:Day 9 Formation and closure of anterior neuropore.JPG|100px|Day 9 File:Day 9.5 Formation of posterior neuropore and forelimb bud.JPG|100px|Day 9.5 File:Day 10.5 Deep Lens Indentation.JPG|100px|Day 10.5 File:Day 11 Closure of lens vesicle.JPG|100px|Day 11 File:Day 11.5 Lens Vesicle completely separated from surface.JPG|100px|Day 11.5 File:Day 12 Earliest signs of fingers.JPG|100px|Day 12 File:Day 13 Anterior Footplate Indented, marked pinna.JPG|100px|Day 13 File:Day 14 Fingers Separate.JPG|100px|Day 14 File:Day 15 toes separate.JPG|100px|Day 15 File:Day 16 Reposition of umbilical hernia.JPG|100px|Day 16 File:Day 17 fingers and toes joined together.JPG|100px|day 17 File:Day 18 long whiskers.JPG|100px|Day 18 File:Day 19 Newborn Mouse.JPG|100px|Day 19 </gallery>
The above illustrations highlight what can be observed in the mouse embyro throughout its development. They progress from Day 0 (top left) to Day 19 (bottom right).
- Day 0 One Cell Egg
- Day 1 Dividing cells. Cleavage of cells has begun. Day ends with 4 cells present
- Day 2 Formation of Morula
- Day 3 Advanced Segmentation. 16-25 cells within same sized morula.
- Day 4 Blastocyst formation
- Day 4 ½ Implantation and invasion into the uterine epithelium
- Day 5 Formation of the egg cylinder occurs.
- Day 6 Differentiation of Egg Cylinder
- Days 6 ½ Advanced Endodermal Reaction
- Day 7 Amnion formation
- Day 7 ½ Neural Plate, Presomite Stage
- Day 8 First somite formation. Day ends with 1 - 7 somites present
- Day 8 ½ Rotation of the Embryo. 8 - 12 somites present
- Day 9 Formation and Closure of the anterior neuropore. 13 - 20 somites present in the embryo
- Day 9 ½ Formation of the posterior neuropore and forelimb bud. There are 21 - 29 somites present. The embryo is 1.8 - 3.3 mm.
- Day 10 Closure of the posterior neuropore and hind limb bud and tail bud formation occurs. 30-34 somites present and the embryo is 3.1-3.9mm.
- Day 10 ½ Deep lens indentation occurs. There are 35-30 somites present and the embryo is now 3.5-4.9mm.
- Day 11 The lens vesicle closes. There are 40-44 somites present and the embryo has reached 5-6mm in length.
- Day 11 ½ The lens vesicle is now completely spearated from the surface of the embryo. There are currently 45 - 47 somites and the embryo reaches a length of 6 - 7mm
- Day 12 Features the earliest signs of fingers forming. The embryo is 7 - 9mm in length from crown to rump and there are 48 - 51 somites.
- Day 13 The footplate becomes indented with the early toe structures. The pinna (external ear) development occurs rapidly. The embryo is now 9 - 11mm in length and has 52 - 55 somites.
- Day 14 The fingers begin to separate distally. The embryo has 56 - 66 somites and is 11-12mm in length.
- Day 15 The toes separate. at this stage, the embryo is 12 - 144m from crown to rump.
- Day 16 The umbilical hernia is repositioned. The fetus now measures between 14 and 17 mm.
- Day 17 The Fingers and Toes align and join together. The skin is wrinkled and thickened and the umbilical hernia has disappeared. The fetus measures 16.5 - 20mm depending on the degree of curvature.
- Day 18 The whiskers have increased in length dramatically. The length of the embryo varies between 18 and 23 mm due to the degree of curvature of the fetus.
- Day 19 The Newborn mouse is between 23 and 27 mm due to varying degrees of flexure of the body axis.
