The Art of Making a Joint

Formation of the skeleton's long bones during development of the vertebrate embryo is well established. However, introduction of articulations or joints in between the bones has not been well characterized. In a Perspective, [Spitz and Duboule][1] explain the part played by Wnt14 (a member of the Wnt family of signaling molecules) in specifying areas called interzones within the primordial bone tissue that will eventually form the joints. [1]: http://www.sciencemag.org/cgi/content/full/291/5509/1713