RT Journal
A1 Lyons, Karen
A1 Ezaki, Marybeth
T1 Molecular Regulation of Limb Growth
JF The Journal of Bone & Joint Surgery
JO The Journal of Bone & Joint Surgery
YR 2009
FD July 1
VO 91
IS Supplement_4
SP 47
OP 52
DO 10.2106/JBJS.I.00240
UL http://dx.doi.org/10.2106/JBJS.I.00240
AB 
The ingenious work of Riddle et al.1, Tickle2, and others in manipulating limbs in chick embryos provided the basic understanding of limb development. It was such work that defined the terms as well as the role of the apical ectodermal ridge, the progress zone, and the zone of polarizing activity in patterning early limb development. Embryology has moved beyond the primitive understanding of which structures form when, into the molecular realm of developmental biology and genetics. As the signaling pathways for limb differentiation become well understood at a molecular level, morphological anomalies in limbs are seen as patterning errors and offer clues to the role of both genetic and epigenetic effects.