Influence of extrinsic factors on the development of the articular system.

In the present study, the results obtained after embryonic movements were paralyzed are described. Paralysis was produced by succinylcholine administered to chicken embryos during Hamburger-Hamilton's stages 25-29. The study of microscopic sections across all the articulations emphasize the absence of articular cavity formation. The cavities were replaced by a non-differentiated mass of mesenchymatous tissue. Regression of articular cavities and para-articular structures was noted in already formed embryos. Contrary to the opinion sustained by some authors, modifications on the articular surfaces were not produced. All of these data, reveal the importance of embryonic movements in articulation formation and conservation.