Spatial and temporal patterns of muscle cleavage in the chick thigh and their value as criteria for homology
Article first published online: 3 FEB 2005
Copyright © 1991 Wiley-Liss, Inc.
American Journal of Anatomy
Volume 191, Issue 4, pages 325–350, August 1991
How to Cite
Schroeter, S. and Tosney, K. W. (1991), Spatial and temporal patterns of muscle cleavage in the chick thigh and their value as criteria for homology. Am. J. Anat., 191: 325–350. doi: 10.1002/aja.1001910402
- Issue published online: 3 FEB 2005
- Article first published online: 3 FEB 2005
- Manuscript Accepted: 25 FEB 1991
- Manuscript Received: 23 MAY 1990
Regions of lower cell density, called cleavage zones, emerge within the dorsal and ventral muscle masses in the vertebrate limb to separate distinct muscles. In the chick thigh, the stereotyped patterns of separation have been broadly outlined, but differences in interpretation exist because no criteria for separation have been defined, and the tissues of the limb are indistinct early in development. We have examined the cleavage process using modern applications of light microscopy and immunocytochemistry to completely detail the spatial and temporal progression of cleavage in stage 27–32 embryos. We find that each muscle has a complex but characteristic pattern of separation along the proximodistal axis. The complex pattern of separation is not related to the positions of muscles within the thigh, locations of blood vessels, activity patterns of muscles, or innervation patterns. The initial separation patterns are more straightforward than later separations and may be of value in determining the phylogenetic history of limb muscles since the same patterns are common to many tetrapods. Our detailed documentation clarifies the ontogeny of the thigh musculature and reveals more complex separation patterns between muscles than previously described.