TY - JOUR T1 - Upper-Limb Evolution and Development: Skeletons in the ClosetCongenital Anomalies and Evolution's Template AU - Ladd, Amy L. Y1 - 2009/07/01 N1 - 10.2106/JBJS.I.00284 JO - The Journal of Bone & Joint Surgery SP - 19 EP - 25 VL - 91 IS - Supplement_4 N2 - The human hand evolved from a specialized fin some 400 million years ago, and its many shapes and purposes have culminated in a masterful instrument capable of great skill—and a source of great despair. When things go awry in development, aberrancies range from the appearance of simple webbing and skin tags to the disappearance of the radius and mirror hand duplication. As surprising and rare as these conditions are, they occur in patterns of morphologic consistencies, although the inciting genetic programming and signaling pathways are complex, interrelated, and only provisionally understood. Identifying the gene's role in evolution has hallmarked much of evolutionary study in the twentieth century, with the discovery of genetic aberrations associated with anomalies often providing a clue to the normal orchestration and development of the limb bud. SN - 0021-9355 M3 - doi: 10.2106/JBJS.I.00284 UR - http://dx.doi.org/10.2106/JBJS.I.00284 ER -