Talk:Carnegie stage 21
From Embryology
Carnegie Collection
Tissue Development
Abdominal Wall Muscle
Carnegie stage 21 (E54) the myoblasts have reached the ventral midline and myotubes were present and oriented uniformly within all muscle groups. The rectus abdominis formed distinct bundles of muscle indicating that development and differentiation of this muscle were more prominent in humans than in mice. Similar to the mouse embryo at E14.5, the connective tissue layers comprised the majority of the thickness of the abdominal wall at CS 21. Furthermore, the outermost layer of connective tissue accounted for the majority of this thickness. PMID 22976993