Template:Abdominal Wall Muscle Timeline table

Abdominal Wall Muscle Timeline

Carnegie Stage	Day	Mouse	Event
14	33	E10.5	mesoderm of primary body wall non-compact, coalesced in the ventral midline to create the abdominal cavity. Liver and stomach present. Dermomyotomes that are derived from somites have been formed.
16	40		the extent or distance of the migration was about 25% of the hemicircumference of the abdominal cavity. As seen in the mouse, the lateral plate mesoderm has become more condensed and thicker in the area around the myoblasts. The primary abdominal wall ventral to this region was thinner and less dense. This suggests that not only myoblasts but also the connective tissue may migrate into the primary body wall or may have active cell proliferation.
17	42	E11.5	cells now migrated about 50% of the distance to the ventral midline. Inner and outer layers not yet not discernible.
18	44	E12.5	Separation of myoblasts into distinct inner and outer layers. The myoblasts in both the inner and outer layers began to exhibit unidirectional orientation. The abdominal wall was thicker (500 μm) in the region where secondary structures were forming compared with the primary body wall region (260 μm). In the more dorsally positioned regions, the outermost layer of connective tissue comprised approximately half of this thickness.
19	48		Segregation of the myoblasts into four distinct muscle groups with unidirectional orientation of myoblasts. Myoblasts migrated over half of the distance to the ventral midline. Abdominal wall remains thickest in the area where the muscles migrated and again the outermost layer of connective tissue comprises approximately half of the total thickness of the abdominal wall in this region. In contrast the primary abdominal wall that is ventral to the migrating myoblasts was noticeably thinner. In mouse the rectus is not segregated from the other muscles until reaching the midline, human rectus was completely separated after migrating over half the distance to the midline.
21	54	E14.5	Myoblasts have reached the ventral midline and myotubes were present and oriented uniformly within all muscle groups. Rectus abdominis formed distinct bundles of muscle indicating that development and differentiation of this muscle were more prominent in humans than in mice. Connective tissue layers form majority of the thickness of the abdominal wall, outermost layer of connective tissue majority of thickness.
23	58	the rectus muscle was forming 2 or 3 distinct layers and myotube orientation remained uniform in all muscles. The external oblique and internal oblique started to expand in terms of thickness whereas the transversus remained a thin layer of muscle. The thickness of the connective tissue was reduced similar to that in the mouse at E15.5. The orientation of connective tissue layers in the obliques and transversus abdominis was dorsal to ventral.
Table Data